Provided by: vdirsyncer_0.16.7-2_all bug

NAME

       vdirsyncer - vdirsyncer Documentation

       • DocumentationSource code

       Vdirsyncer  is  a  command-line  tool  for  synchronizing calendars and addressbooks between a variety of
       servers and the local filesystem. The most popular usecase is to synchronize a server with a local folder
       and use a set of other programs to change the local events and contacts.  Vdirsyncer can then synchronize
       those changes back to the server.

       However, vdirsyncer is not limited to synchronizing between clients and servers. It can also be  used  to
       synchronize calendars and/or addressbooks between two servers directly.

       It aims to be for calendars and contacts what OfflineIMAP is for emails.

WHEN DO I NEED VDIRSYNCER?

   Why not Dropbox + todo.txt?
       Projects like todo.txt criticize the complexity of modern productivity apps, and that rightfully. So they
       set out to create a new, super-simple, human-readable format, such that vim suffices for viewing the  raw
       data. However, when they're faced with the question how to synchronize that data across multiple devices,
       they seemed to have reached the dead end with their novel idea: "Let's just use Dropbox".

       What does file sync software do if both files have changed since the last sync?  The answer is to  ignore
       the  question,  just  sync  as  often  as  possible, and hope for the best. Because if it comes to a sync
       conflict, most sync services are not daring to merge files,  and  create  two  copies  on  each  computer
       instead.  Merging the two task lists is left to the user.

       A  better  idea  would've  been  to  use  git to synchronize the todo.txt file, which is at least able to
       resolve some basic conflicts.

   Why not file sync (Dropbox, git, ...) + vdir?
       Since vdirs are just a bunch of files, it is obvious to try file synchronization for  synchronizing  your
       data between multiple computers, such as:

       • SyncthingDropbox or one of the gajillion services like it

       • unison

       • Just git with a sshd.

       The disadvantages of those solutions largely depend on the exact file sync program chosen:

       • Like  with  todo.txt,  Dropbox  and friends are obviously agnostic/unaware of the files' contents. If a
         file has changed on both sides, Dropbox just copies both versions to both sides.

         This is a good idea if the user is directly interfacing with the file system and  is  able  to  resolve
         conflicts themselves.  Here it might lead to erroneous behavior with e.g. khal, since there are now two
         events with the same UID.

         This point doesn't apply to git: It has very good merging capabilities,  better  than  what  vdirsyncer
         currently has.

       • Such  a  setup  doesn't  work at all with smartphones. Vdirsyncer, on the other hand, synchronizes with
         CardDAV/CalDAV servers, which can be accessed with e.g. DAVDroid or the apps by dmfs.

INSTALLATION

   OS/distro packages
       The following packages are user-contributed and were up-to-date at the time of writing:

       • ArchLinux (AUR)Ubuntu and Debian, x86_64-only (packages also exist in the official repositories  but  may  be  out  of
         date)

       • GNU GuixOS X (homebrew)BSD (pkgsrc)OpenBSD

       We  only support the latest version of vdirsyncer, which is at the time of this writing 0.16.7. Please do
       not file bugs if you use an older version.

       Some distributions have multiple release channels. Debian and Fedora for example have a "stable"  release
       channel that ships an older version of vdirsyncer. Those versions aren't supported either.

       If  there is no suitable package for your distribution, you'll need to install vdirsyncer manually. There
       is an easy command to copy-and-paste for this as well, but you should be aware of its consequences.

   Manual installation
       If your distribution doesn't provide a package for vdirsyncer, you still can use Python's package manager
       "pip". First, you'll have to check that the following things are installed:

       • Python 3.4+ and pip.

       • libxml and libxsltzlib

       • Linux or OS X. Windows is not supported, see :gh:`535`.

       On  Linux  systems,  using  the  distro's  package manager is the best way to do this, for example, using
       Ubuntu:

          sudo apt-get install libxml2 libxslt1.1 zlib1g python

       Then you have several options. The following text applies for most Python software by the way.

   The dirty, easy way
       The easiest way to install vdirsyncer at this point would be to run:

          pip install --user --ignore-installed vdirsyncer

       • --user is to install without root rights (into your home directory)

       • --ignore-installed is to work around Debian's potentially broken packages (see debian-urllib3).

       This method has a major flaw though: Pip doesn't keep track of the files it installs. Vdirsyncer's  files
       would  be  located  somewhere  in  ~/.local/lib/python*,  but you can't possibly know which packages were
       installed as dependencies of vdirsyncer and which ones were not, should you decide to  uninstall  it.  In
       other words, using pip that way would pollute your home directory.

   The clean, hard way
       There  is  a  way to install Python software without scattering stuff across your filesystem: virtualenv.
       There are a lot of resources on how to use it, the simplest possible way would look something like:

          virtualenv ~/vdirsyncer_env
          ~/vdirsyncer_env/bin/pip install vdirsyncer
          alias vdirsyncer="~/vdirsyncer_env/bin/vdirsyncer

       You'll have to put the last line into your .bashrc or .bash_profile.

       This method has two advantages:

       • It separately installs all Python packages  into  ~/vdirsyncer_env/,  without  relying  on  the  system
         packages. This works around OS- or distro-specific issues.

       • You can delete ~/vdirsyncer_env/ to uninstall vdirsyncer entirely.

   The clean, easy way
       pipsi is a new package manager for Python-based software that automatically sets up a virtualenv for each
       program you install. Assuming you have it installed on your operating system, you can do:

          pipsi install --python python3 vdirsyncer

       and .local/bin/vdirsyncer will be your new vdirsyncer installation. To update vdirsyncer  to  the  latest
       version:

          pipsi upgrade vdirsyncer

       If you're done with vdirsyncer, you can do:

          pipsi uninstall vdirsyncer

       and vdirsyncer will be uninstalled, including its dependencies.

TUTORIAL

       Before  starting,  consider  if you actually need vdirsyncer. There are better alternatives available for
       particular usecases.

   Installation
       See installation.

   Configuration
       NOTE:

          • The config.example from the repository contains a very terse version of this.

          • In this example we set up contacts synchronization, but calendar sync works almost  the  same.  Just
            swap type = "carddav" for type = "caldav" and fileext = ".vcf" for fileext = ".ics".

          • Take a look at the problems page if anything doesn't work like planned.

       By default, vdirsyncer looks for its configuration file in the following locations:

       • The file pointed to by the VDIRSYNCER_CONFIG environment variable.

       • ~/.vdirsyncer/config.

       • $XDG_CONFIG_HOME/vdirsyncer/config,  which is normally ~/.config/vdirsyncer/config. See the XDG-Basedir
         specification.

       The config file should start with a general section, where the only required  parameter  is  status_path.
       The following is a minimal example:

          [general]
          status_path = "~/.vdirsyncer/status/"

       After the general section, an arbitrary amount of pair and storage sections might come.

       In  vdirsyncer, synchronization is always done between two storages. Such storages are defined in storage
       sections, and which pairs of storages should actually be synchronized is defined in pair  section.   This
       format is copied from OfflineIMAP, where storages are called repositories and pairs are called accounts.

       The following example synchronizes ownCloud's addressbooks to ~/.contacts/:

          [pair my_contacts]
          a = "my_contacts_local"
          b = "my_contacts_remote"
          collections = ["from a", "from b"]

          [storage my_contacts_local]
          type = "filesystem"
          path = "~/.contacts/"
          fileext = ".vcf"

          [storage my_contacts_remote]
          type = "carddav"

          # We can simplify this URL here as well. In theory it shouldn't matter.
          url = "https://owncloud.example.com/remote.php/carddav/"
          username = "bob"
          password = "asdf"

       NOTE:
          Configuration for other servers can be found at supported-servers.

       After  running  vdirsyncer  discover  and  vdirsyncer sync, ~/.contacts/ will contain subfolders for each
       addressbook, which in turn will contain a bunch of .vcf files which all contain a contact in VCARD format
       each.   You  can  modify  their  contents,  add  new  ones  and delete some [1], and your changes will be
       synchronized to the CalDAV server after you run vdirsyncer sync again. For further reference, it uses the
       storages filesystem and carddav.

       However,  if  new  collections  are  created on the server, it will not automatically start synchronizing
       those [2]. You need to run vdirsyncer discover again to re-fetch this list instead.

       [1]  You'll want to use a helper program for this.

       [2]  Because collections are added rarely, and checking for this case before every synchronization  isn't
            worth the overhead.

   More Configuration
   Conflict resolution
       What  if  the  same item is changed on both sides? What should vdirsyncer do? Three options are currently
       provided:

       1. vdirsyncer displays an error message (the default);

       2. vdirsyncer chooses one alternative version over the other;

       3. vdirsyncer starts a command of your choice that is supposed to merge the two alternative versions.

       Options 2 and 3 require adding a "conflict_resolution" parameter to the pair section. Option  2  requires
       giving either "a wins" or "b wins" as value to the parameter:

          [pair my_contacts]
          ...
          conflict_resolution = "b wins"

       Earlier we wrote that b = "my_contacts_remote", so when vdirsyncer encounters the situation where an item
       changed on both sides, it will simply overwrite the local item with the one from the server.

       Option 3 requires specifying as value of "conflict_resolution"  an  array  starting  with  "command"  and
       containing paths and arguments to a command. For example:

          [pair my_contacts]
          ...
          conflict_resolution = ["command", "vimdiff"]

       In this example, vimdiff <a> <b> will be called with <a> and <b> being two temporary files containing the
       conflicting files. The files need to be exactly the same when the command returns. More arguments can  be
       passed to the command by adding more elements to the array.

       See pair_config for the reference documentation.

   Metadata synchronization
       Besides   items,   vdirsyncer  can  also  synchronize  metadata  like  the  addressbook's  or  calendar's
       "human-friendly" name (internally called "displayname") or the color associated with a calendar. For  the
       purpose of explaining this feature, let's switch to a different base example. This time we'll synchronize
       calendars:

          [pair my_calendars]
          a = "my_calendars_local"
          b = "my_calendars_remote"
          collections = ["from a", "from b"]
          metadata = ["color"]

          [storage my_calendars_local]
          type = "filesystem"
          path = "~/.calendars/"
          fileext = ".ics"

          [storage my_calendars_remote]
          type = "caldav"

          url = "https://owncloud.example.com/remote.php/caldav/"
          username = "bob"
          password = "asdf"

       Run vdirsyncer discover for discovery. Then you can use vdirsyncer  metasync  to  synchronize  the  color
       property  between  your  local  calendars  in  ~/.calendars/ and your ownCloud. Locally the color is just
       represented as a file called color within the calendar folder.

   More information about collections
       "Collection" is a collective term for addressbooks and calendars. Each collection from a  storage  has  a
       "collection  name",  a  unique identifier for each collection. In the case of filesystem-storage, this is
       the name of the directory that represents the collection, in the case of the  DAV-storages  this  is  the
       last segment of the URL. We use this identifier in the collections parameter in the pair-section.

       This  identifier  doesn't  change  even if you rename your calendar in whatever UI you have, because that
       only changes the so-called "displayname" property [3].  On some servers (iCloud, Google) this  identifier
       is randomly generated and has no correlation with the displayname you chose.

       [3]  Which you can also synchronize with metasync using metadata = ["displayname"].

            There are three collection names that have a special meaning:

       • "from  a",  "from  b":  A  placeholder  for  all collections that can be found on side A/B when running
         vdirsyncer discover.

       • null: The parameters give to the storage are exact and require no discovery.

       The last one requires a bit more explanation.  Assume this config which synchronizes two  directories  of
       addressbooks:

          [pair foobar]
          a = "foo"
          b = "bar"
          collections = ["from a", "from b"]

          [storage foo]
          type = "filesystem"
          fileext = ".vcf"
          path = "./contacts_foo/"

          [storage bar]
          type = "filesystem"
          fileext = ".vcf"
          path = "./contacts_bar/"

       As  we  saw  previously  this  will  synchronize  all collections in ./contacts_foo/ with each same-named
       collection in ./contacts_bar/. If there's a collection that  exists  on  one  side  but  not  the  other,
       vdirsyncer will ask whether to create that folder on the other side.

       If  we  set collections = null, ./contacts_foo/ and ./contacts_bar/ are no longer treated as folders with
       collections, but as collections themselves. This means  that  ./contacts_foo/  and  ./contacts_bar/  will
       contain .vcf-files, not subfolders that contain .vcf-files.

       This  is useful in situations where listing all collections fails because your DAV-server doesn't support
       it, for example. In this case, you can set url of your carddav- or caldav-storage to a URL that points to
       your CalDAV/CardDAV collection directly.

       Note  that  not all storages support the null-collection, for example google_contacts and google_calendar
       don't.

   Advanced collection configuration (server-to-server sync)
       The examples above are good enough if you want to synchronize a remote server to a previously empty disk.
       However, even more trickery is required when you have two servers with already existing collections which
       you want to synchronize.

       The core problem in this situation is that vdirsyncer pairs collections by  collection  name  by  default
       (see definition in previous section, basically a foldername or a remote UUID). When you have two servers,
       those collection names may not line up as nicely. Suppose you created two  calendars  "Test",  one  on  a
       NextCloud  server  and one on iCloud, using their respective web interfaces. The URLs look something like
       this:

          NextCloud: https://example.com/remote.php/dav/calendars/user/test/
          iCloud:    https://p-XX.caldav.icloud.com/YYY/calendars/3b4c9995-5c67-4021-9fa0-be4633623e1c

       Those   are   two   DAV   calendar   collections.   Their   collection   names   will   be    test    and
       3b4c9995-5c67-4021-9fa0-be4633623e1c  respectively,  so you don't have a single name you can address them
       both with. You will need to manually "pair" (no pun intended) those collections up like this:

          [pair doublecloud]
          a = "my_nextcloud"
          b = "my_icloud"
          collections = [["mytest", "test", "3b4c9995-5c67-4021-9fa0-be4633623e1c"]]

       mytest gives that combination of calendars a nice name you can use when talking about it,  so  you  would
       use  vdirsyncer  sync  doublecloud/mytest to say: "Only synchronize these two storages, nothing else that
       may be configured".

       NOTE:
          Why not use displaynames?

          You may wonder why vdirsyncer just couldn't figure this out by itself. After all, you  did  name  both
          collections "Test" (which is called "the displayname"), so why not pair collections by that value?

          There are a few problems with this idea:

          • Two calendars may have the same exact displayname.

          • A calendar may not have a (non-empty) displayname.

          • The displayname might change. Either you rename the calendar, or the calendar renames itself because
            you change a language setting.

          In the end, that property was never designed to be parsed by machines.

SSL AND CERTIFICATE VALIDATION

       All SSL configuration is done per-storage.

   Pinning by fingerprint
       To pin the certificate by fingerprint:

          [storage foo]
          type = "caldav"
          ...
          verify_fingerprint = "94:FD:7A:CB:50:75:A4:69:82:0A:F8:23:DF:07:FC:69:3E:CD:90:CA"
          #verify = false  # Optional: Disable CA validation, useful for self-signed certs

       SHA1-, SHA256- or MD5-Fingerprints can be used. They're detected by their length.

       You can use the following command for obtaining a SHA-1 fingerprint:

          echo -n | openssl s_client -connect unterwaditzer.net:443 | openssl x509 -noout -fingerprint

       Note that verify_fingerprint doesn't suffice for vdirsyncer to work  with  self-signed  certificates  (or
       certificates  that are not in your trust store). You most likely need to set verify = false as well. This
       disables verification of the SSL certificate's expiration time and the existence  of  it  in  your  trust
       store, all that's verified now is the fingerprint.

       However,  please consider using Let's Encrypt such that you can forget about all of that. It is easier to
       deploy a free certificate from them than configuring all  of  your  clients  to  accept  the  self-signed
       certificate.

   Custom root CAs
       To point vdirsyncer to a custom set of root CAs:

          [storage foo]
          type = "caldav"
          ...
          verify = "/path/to/cert.pem"

       Vdirsyncer uses the requests library, which, by default, uses its own set of trusted CAs.

       However,  the  actual behavior depends on how you have installed it. Many Linux distributions patch their
       python-requests package to use the system certificate CAs. Normally these two stores are  similar  enough
       for you to not care.

       But there are cases where certificate validation fails even though you can access the server fine through
       e.g. your browser. This usually indicates that your installation  of  the  requests  library  is  somehow
       broken. In such cases, it makes sense to explicitly set verify or verify_fingerprint as shown above.

   Client Certificates
       Client  certificates may be specified with the auth_cert parameter. If the key and certificate are stored
       in the same file, it may be a string:

          [storage foo]
          type = "caldav"
          ...
          auth_cert = "/path/to/certificate.pem"

       If the key and certificate are separate, a list may be used:

          [storage foo]
          type = "caldav"
          ...
          auth_cert = ["/path/to/certificate.crt", "/path/to/key.key"]

STORING PASSWORDS

       Changed in version 0.7.0: Password configuration got completely overhauled.

       Vdirsyncer can fetch passwords from several sources other than the config file.

   Command
       Say you have the following configuration:

          [storage foo]
          type = "caldav"
          url = ...
          username = "foo"
          password = "bar"

       But it bugs you that the password is stored in cleartext in the config file.  You can do this:

          [storage foo]
          type = "caldav"
          url = ...
          username = "foo"
          password.fetch = ["command", "~/get-password.sh", "more", "args"]

       You can fetch the username as well:

          [storage foo]
          type = "caldav"
          url = ...
          username.fetch = ["command", "~/get-username.sh"]
          password.fetch = ["command", "~/get-password.sh"]

       Or really any kind of parameter in a storage section.

       With pass for example, you might find yourself writing something like this in your configuration file:

          password.fetch = ["command", "pass", "caldav"]

   Accessing the system keyring
       As shown above, you can use the command strategy to fetch your credentials from arbitrary sources. A very
       common usecase is to fetch your password from the system keyring.

       The  keyring Python package contains a command-line utility for fetching passwords from the OS's password
       store. Installation:

          pip install keyring

       Basic usage:

          password.fetch = ["command", "keyring", "get", "example.com", "foouser"]

   Password Prompt
       You can also simply prompt for the password:

          [storage foo]
          type = "caldav"
          username = "myusername"
          password.fetch = ["prompt", "Password for CalDAV"]

SYNCING WITH READ-ONLY STORAGES

       If you want to subscribe to a public, read-only WebCAL-calendar but neither your server nor your calendar
       apps  support  that  (or  support it insufficiently), vdirsyncer can be used to synchronize such a public
       calendar A with a new calendar B of your own and keep B updated.

   Step 1: Create the target calendar
       First you need to create the calendar you want to sync the WebCAL-calendar with. Most servers offer a web
       interface  for  this.  You  then  need to note the CalDAV URL of your calendar. Note that this URL should
       directly point to the calendar you just created, which means  you  would  have  one  such  URL  for  each
       calendar you have.

   Step 2: Creating the config
       Paste this into your vdirsyncer config:

          [pair holidays]
          a = "holidays_public"
          b = "holidays_private"
          collections = null

          [storage holidays_public]
          type = "http"
          # The URL to your iCalendar file.
          url = ...

          [storage holidays_private]
          type = "caldav"
          # The direct URL to your calendar.
          url = ...
          # The credentials to your CalDAV server
          username = ...
          password = ...

       Then  run vdirsyncer discover holidays and vdirsyncer sync holidays, and your previously created calendar
       should be filled with events.

   Step 3: The partial_sync parameter
       New in version 0.14.

       You may get into a situation where you want to hide or modify some events from your holidays calendar. If
       you try to do that at this point, you'll notice that vdirsyncer will revert any changes you've made after
       a few times of running sync. This is because vdirsyncer wants to keep everything in sync,  and  it  can't
       synchronize changes to the public holidays-calendar because it doesn't have the rights to do so.

       For such purposes you can set the partial_sync parameter to ignore:

          [pair holidays]
          a = "holidays_public"
          b = "holidays_private"
          collections = null
          partial_sync = ignore

       See the config docs for more information.

FULL CONFIGURATION MANUAL

       Vdirsyncer  uses an ini-like format for storing its configuration. All values are JSON, invalid JSON will
       get interpreted as string:

          x = "foo"  # String
          x = foo  # Shorthand for same string

          x = 42  # Integer

          x = ["a", "b", "c"]  # List of strings

          x = true  # Boolean
          x = false

          x = null  # Also known as None

   General Section
          [general]
          status_path = ...

       • status_path: A directory where vdirsyncer will store some additional data for the next sync.

         The data is needed to determine whether a new item means it has been added on one side  or  deleted  on
         the other. Relative paths will be interpreted as relative to the configuration file's directory.

         See A simple synchronization algorithm for what exactly is in there.

   Pair Section
          [pair pair_name]
          a = ...
          b = ...
          #collections = null
          #conflict_resolution = null

       • Pair names can consist of any alphanumeric characters and the underscore.

       • a and b reference the storages to sync by their names.

       • collections:  A  list  of  collections  to  synchronize  when  vdirsyncer  sync  is  executed. See also
         collections_tutorial.

         The special values "from a" and "from b", tell vdirsyncer to try autodiscovery on a specific storage.

         If the collection you want to sync doesn't have the same name on each side, you may also use a value of
         the  form  ["config_name",  "name_a", "name_b"].  This will synchronize the collection name_a on side A
         with the collection name_b on side B. The config_name will be used for representation in CLI  arguments
         and logging.

         Examples:

         • collections  = ["from b", "foo", "bar"] makes vdirsyncer synchronize the collections from side B, and
           also the collections named "foo" and "bar".

         • collections = ["from b", "from a"] makes vdirsyncer synchronize all existing  collections  on  either
           side.

         • collections  = [["bar", "bar_a", "bar_b"], "foo"] makes vdirsyncer synchronize bar_a from side A with
           bar_b from side B, and also synchronize foo on both sides with each other.

       • conflict_resolution: Optional, define how conflicts should be handled.  A conflict occurs when one item
         (event, task) changed on both sides since the last sync. See also conflict_resolution_tutorial.

         Valid values are:

         • null, where an error is shown and no changes are done.

         • "a wins" and "b wins", where the whole item is taken from one side.

         • ["command",  "vimdiff"]:  vimdiff  <a>  <b> will be called where <a> and <b> are temporary files that
           contain the item of each side respectively. The files need to be exactly the same  when  the  command
           returns.

           • vimdiff  can  be  replaced  with  any  other  command.  For  example, in POSIX ["command", "cp"] is
             equivalent to "a wins".

           • Additional list  items  will  be  forwarded  as  arguments.  For  example,  ["command",  "vimdiff",
             "--noplugin"] runs vimdiff --noplugin.

         Vdirsyncer never attempts to "automatically merge" the two items.

       • partial_sync: Assume A is read-only, B not. If you change items on B, vdirsyncer can't sync the changes
         to A. What should happen instead?

         • error: An error is shown.

         • ignore: The change is ignored. However: Events deleted in B still reappear if they're updated in A.

         • revert (default): The change is reverted on next sync.

         See also partial_sync_tutorial.

       • metadata: Metadata keys that should be synchronized when vdirsyncer metasync is executed. Example:

            metadata = ["color", "displayname"]

         This synchronizes the color and the displayname properties. The conflict_resolution  parameter  applies
         here as well.

   Storage Section
          [storage storage_name]
          type = ...

       • Storage names can consist of any alphanumeric characters and the underscore.

       • type defines which kind of storage is defined. See Supported Storages.

       • read_only  defines  whether the storage should be regarded as a read-only storage. The value true means
         synchronization will discard any changes made to the other side. The value false implies  normal  2-way
         synchronization.

       • Any further parameters are passed on to the storage class.

   Supported Storages
   CalDAV and CardDAV
       NOTE:
          Please also see supported-servers, as some servers may not work well.

       caldav CalDAV.

                 [storage example_for_caldav]
                 type = "caldav"
                 #start_date = null
                 #end_date = null
                 #item_types = []
                 url = "..."
                 #username = ""
                 #password = ""
                 #verify = true
                 #auth = null
                 #useragent = "vdirsyncer/0.16.4"
                 #verify_fingerprint = null
                 #auth_cert = null

              You  can  set a timerange to synchronize with the parameters start_date and end_date. Inside those
              parameters, you can use any Python expression to return  a  valid  datetime.datetime  object.  For
              example,  the  following  would synchronize the timerange from one year in the past to one year in
              the future:

                 start_date = "datetime.now() - timedelta(days=365)"
                 end_date = "datetime.now() + timedelta(days=365)"

              Either both or none have to be specified. The default is to synchronize everything.

              You can set item_types to restrict the kind of items you want to synchronize. For example, if  you
              want  to  only synchronize events (but don't download any tasks from the server), set item_types =
              ["VEVENT"]. If you want to synchronize events and tasks, but  have  some  VJOURNAL  items  on  the
              server you don't want to synchronize, use item_types = ["VEVENT", "VTODO"].

              Parametersstart_date -- Start date of timerange to show, default -inf.

                     • end_date -- End date of timerange to show, default +inf.

                     • item_types  --  Kind  of items to show. The default, the empty list, is to show all. This
                       depends on particular features on the server, the results are not validated.

                     • url -- Base URL or an URL to a calendar.

                     • username -- Username for authentication.

                     • password -- Password for authentication.

                     • verify -- Verify SSL certificate, default True. This can  also  be  a  local  path  to  a
                       self-signed SSL certificate. See ssl-tutorial for more information.

                     • verify_fingerprint   --  Optional.  SHA1  or  MD5  fingerprint  of  the  expected  server
                       certificate. See ssl-tutorial for more information.

                     • auth -- Optional. Either basic, digest or guess. The default is  preemptive  Basic  auth,
                       sending  credentials  even  if  server didn't request them. This saves from an additional
                       roundtrip per request. Consider setting guess if this causes issues with your server.

                     • auth_cert -- Optional. Either a path to a certificate with a client certificate  and  the
                       key or a list of paths to the files with them.

                     • useragent -- Default vdirsyncer.

       carddav
              CardDAV.

                 [storage example_for_carddav]
                 type = "carddav"
                 url = "..."
                 #username = ""
                 #password = ""
                 #verify = true
                 #auth = null
                 #useragent = "vdirsyncer/0.16.4"
                 #verify_fingerprint = null
                 #auth_cert = null

              Parametersurl -- Base URL or an URL to an addressbook.

                     • username -- Username for authentication.

                     • password -- Password for authentication.

                     • verify  --  Verify  SSL  certificate,  default  True.  This can also be a local path to a
                       self-signed SSL certificate. See ssl-tutorial for more information.

                     • verify_fingerprint  --  Optional.  SHA1  or  MD5  fingerprint  of  the  expected   server
                       certificate. See ssl-tutorial for more information.

                     • auth  --  Optional.  Either basic, digest or guess. The default is preemptive Basic auth,
                       sending credentials even if server didn't request them. This  saves  from  an  additional
                       roundtrip per request. Consider setting guess if this causes issues with your server.

                     • auth_cert  --  Optional. Either a path to a certificate with a client certificate and the
                       key or a list of paths to the files with them.

                     • useragent -- Default vdirsyncer.

   Google
       Vdirsyncer supports synchronization with Google calendars with  the  restriction  that  VTODO  files  are
       rejected by the server.

       Synchronization with Google contacts is less reliable due to negligence of Google's CardDAV API. Google's
       CardDAV implementation is allegedly a disaster in terms of data  safety.  See  this  blog  post  for  the
       details.  Always back up your data.

       At first run you will be asked to authorize application for google account access.

       To use this storage type, you need to install some additional dependencies:

          pip install vdirsyncer[google]

       Furthermore  you  need  to  register  vdirsyncer  as  an  application  yourself  to  obtain client_id and
       client_secret, as it is against Google's Terms of Service to  hardcode  those  into  opensource  software
       [googleterms]:

       1. Go to the Google API Manager and create a new project under any name.

       2. Within that project, enable the "CalDAV" and "CardDAV" APIs (not the Calendar and Contacts APIs, those
          are different and won't work). There should be a searchbox where you can just enter those terms.

       3. In the sidebar, select "Credentials" and create a new "OAuth  Client  ID".  The  application  type  is
          "Other".

          You'll be prompted to create a OAuth consent screen first. Fill out that form however you like.

       4. Finally you should have a Client ID and a Client secret. Provide these in your storage config.

       The  token_file  parameter  should  be a filepath where vdirsyncer can later store authentication-related
       data. You do not need to create the file itself or write anything to it.

       [googleterms]
            See ToS, section "Confidential Matters".

            NOTE:
          You need to configure which calendars Google should offer vdirsyncer using a  rather  hidden  settings
          page.

       google_calendar
              Google calendar.

                 [storage example_for_google_calendar]
                 type = "google_calendar"
                 token_file = "..."
                 client_id = "..."
                 client_secret = "..."
                 #start_date = null
                 #end_date = null
                 #item_types = []

              Please refer to caldav regarding the item_types and timerange parameters.

              Parameterstoken_file -- A filepath where access tokens are stored.

                     • client_id/client_secret -- OAuth credentials, obtained from the Google API Manager.

       google_contacts
              Google contacts.

                 [storage example_for_google_contacts]
                 type = "google_contacts"
                 token_file = "..."
                 client_id = "..."
                 client_secret = "..."

              Parameterstoken_file -- A filepath where access tokens are stored.

                     • client_id/client_secret -- OAuth credentials, obtained from the Google API Manager.

   EteSync
       EteSync  is  a  new  cloud  provider  for  end to end encrypted contacts and calendar storage. Vdirsyncer
       contains experimental support for it.

       To use it, you need to install some optional dependencies:

          pip install vdirsyncer[etesync]

       On first usage you will be prompted for the service password and the  encryption  password.  Neither  are
       stored.

       etesync_contacts
                 Contacts for etesync.

                     [storage example_for_etesync_contacts]
                     email = ...
                     secrets_dir = ...
                     #server_path = ...
                     #db_path = ...

              Parametersemail -- The email address of your account.

                     • secrets_dir   --   A  directory  where  vdirsyncer  can  store  the  encryption  key  and
                       authentication token.

                     • server_url -- Optional. URL to the root of your custom server.

                     • db_path -- Optional. Use a different path for the database.

       etesync_calendars
              Calendars for etesync.

                 [storage example_for_etesync_calendars]
                 email = ...
                 secrets_dir = ...
                 #server_path = ...
                 #db_path = ...

              Parametersemail -- The email address of your account.

                     • secrets_dir  --  A  directory  where  vdirsyncer  can  store  the  encryption   key   and
                       authentication token.

                     • server_url -- Optional. URL to the root of your custom server.

                     • db_path -- Optional. Use a different path for the database.

   Local
       filesystem
              Saves each item in its own file, given a directory.

                 [storage example_for_filesystem]
                 type = "filesystem"
                 path = "..."
                 fileext = "..."
                 #encoding = "utf-8"
                 #post_hook = null

              Can be used with khal. See vdir for a more formal description of the format.

              Directories with a leading dot are ignored to make usage of e.g. version control easier.

              Parameterspath  --  Absolute  path  to  a  vdir/collection. If this is used in combination with the
                       collections parameter in a pair-section, this  should  point  to  a  directory  of  vdirs
                       instead.

                     • fileext -- The file extension to use (e.g. .txt). Contained in the href, so if you change
                       the file extension after a sync, this will  trigger  a  re-download  of  everything  (but
                       should not cause data-loss of any kind).

                     • encoding -- File encoding for items, both content and filename.

                     • post_hook  -- A command to call for each item creation and modification. The command will
                       be called with the path of the new/updated file.

       singlefile
              Save data in single local .vcf or .ics file.

              The storage basically guesses how items should be joined in the file.

              New in version 0.1.6.

              NOTE:
                 This storage is very slow, and that is unlikely to change. You should consider using filesystem
                 if it fits your usecase.

              Parameterspath  --  The filepath to the file to be written to. If collections are used, this should
                       contain %s as a placeholder for the collection name.

                     • encoding -- Which encoding the file should use. Defaults to UTF-8.

              Example for syncing with caldav:

                 [pair my_calendar]
                 a = my_calendar_local
                 b = my_calendar_remote
                 collections = ["from a", "from b"]

                 [storage my_calendar_local]
                 type = "singlefile"
                 path = ~/.calendars/%s.ics

                 [storage my_calendar_remote]
                 type = "caldav"
                 url = https://caldav.example.org/
                 #username =
                 #password =

              Example for syncing with caldav using a null collection:

                 [pair my_calendar]
                 a = my_calendar_local
                 b = my_calendar_remote

                 [storage my_calendar_local]
                 type = "singlefile"
                 path = ~/my_calendar.ics

                 [storage my_calendar_remote]
                 type = "caldav"
                 url = https://caldav.example.org/username/my_calendar/
                 #username =
                 #password =

   Read-only storages
       These storages don't support writing of their items, consequently read_only is set to  true  by  default.
       Changing read_only to false on them leads to an error.

       http   Use  a  simple  .ics  file (or similar) from the web.  webcal://-calendars are supposed to be used
              with this, but you have to replace webcal:// with http://, or better, https://.

                 [pair holidays]
                 a = holidays_local
                 b = holidays_remote
                 collections = null

                 [storage holidays_local]
                 type = "filesystem"
                 path = ~/.config/vdir/calendars/holidays/
                 fileext = .ics

                 [storage holidays_remote]
                 type = "http"
                 url = https://example.com/holidays_from_hicksville.ics

              Too many WebCAL providers generate UIDs of all VEVENT-components on-the-fly, i.e. all UIDs  change
              every  time  the calendar is downloaded.  This leads many synchronization programs to believe that
              all events have been deleted and new ones created, and accordingly causes  a  lot  of  unnecessary
              uploads  and  deletions on the other side. Vdirsyncer completely ignores UIDs coming from http and
              will replace them with a hash of the normalized item content.

              Parametersurl -- URL to the .ics file.

                     • username -- Username for authentication.

                     • password -- Password for authentication.

                     • verify -- Verify SSL certificate, default True. This can  also  be  a  local  path  to  a
                       self-signed SSL certificate. See ssl-tutorial for more information.

                     • verify_fingerprint   --  Optional.  SHA1  or  MD5  fingerprint  of  the  expected  server
                       certificate. See ssl-tutorial for more information.

                     • auth -- Optional. Either basic, digest or guess. The default is  preemptive  Basic  auth,
                       sending  credentials  even  if  server didn't request them. This saves from an additional
                       roundtrip per request. Consider setting guess if this causes issues with your server.

                     • auth_cert -- Optional. Either a path to a certificate with a client certificate  and  the
                       key or a list of paths to the files with them.

                     • useragent -- Default vdirsyncer.

OTHER TUTORIALS

       The following section contains tutorials not explicitly about any particular core function of vdirsyncer.
       They usually show how to integrate vdirsyncer with third-party software. Because of that, it may be  that
       the information regarding that other software only applies to specific versions of them.

       NOTE:
          Please contribute your own tutorials too!  Pages are often only stubs and are lacking full examples.

   Client applications
   Vdirsyncer with Claws Mail
       First  of  all,  Claws-Mail  only supports read-only functions for vCards. It can only read contacts, but
       there's no editor.

   Preparation
       We need to install vdirsyncer, for that look here.  Then we need to create some folders:

          mkdir ~/.vdirsyncer
          mkdir ~/.contacts

   Configuration
       Now we create the configuration for vdirsyncer. Open ~/.vdirsyncer/config with a text editor. The  config
       should look like this:

          [general]
          status_path = "~/.vdirsyncer/status/"

          [storage local]
          type = "singlefile"
          path = "~/.contacts/%s.vcf"

          [storage online]
          type = "carddav"
          url = "CARDDAV_LINK"
          username = "USERNAME"
          password = "PASSWORD"
          read_only = true

          [pair contacts]
          a = "local"
          b = "online"
          collections = ["from a", "from b"]
          conflict_resolution = "b wins"

       • In  the  general  section,  we  define the status folder path, for discovered collections and generally
         stuff that needs to persist between syncs.

       • In the local section we define that all contacts should be sync in a single file and the path  for  the
         contacts.

       • In  the  online  section  you must change the url, username and password to your setup. We also set the
         storage to read-only such that no changes get synchronized back. Claws-Mail should not be  able  to  do
         any changes anyway, but this is one extra safety step in case files get corrupted or vdirsyncer behaves
         eratically. You can leave that part out if you want to be able to edit those files locally.

       • In the last section we configure that online contacts win in a conflict situation. Configure this  part
         however you like. A correct value depends on which side is most likely to be up-to-date.

   Sync
       Now we discover and sync our contacts:

          vdirsyncer discover contacts
          vdirsyncer sync contacts

   Claws Mail
       Open Claws-Mail. Got to Tools => Addressbook.

       Click on Addressbook => New vCard. Choose a name for the book.

       Then  search  for  the  for  the  vCard  in  the  folder ~/.contacts/. Click ok, and you we will see your
       contacts.

       NOTE:
          Claws-Mail shows only contacts that have a mail address.

   Crontab
       On the end we create a crontab, so that vdirsyncer syncs automatically every 30 minutes our contacts:

          contab -e

       On the end of that file enter this line:

          */30 * * * * /usr/local/bin/vdirsyncer sync > /dev/null

       And you're done!

   Running as a systemd.timer
       vdirsyncer includes unit files to run at an interval (by default every 15±5 minutes).

       NOTE:
          These are not installed when installing via pip, only via distribution packages. If you installed  via
          pip,  or your distribution doesn't ship systemd unit files, you'll need to download vdirsyncer.service
          and vdirsyncer.timer into either /etc/systemd/user/ or ~/.local/share/systemd/user.

   Activation
       To activate the timer, just run systemctl --user enable vdirsyncer.timer.  To see logs of previous  runs,
       use journalctl --user -u vdirsyncer.

   Configuration
       It's  quite  possible  that the default "every fifteen minutes" interval isn't to your liking. No default
       will suit everybody, but this is configurable by simply running:

          systemctl --user edit vdirsyncer

       This will open a blank editor, where you can override the timer by including:

          OnBootSec=5m  # This is how long after boot the first run takes place.
          OnUnitActiveSec=15m  # This is how often subsequent runs take place.

   Todoman
       The iCalendar format also supports saving tasks in form of VTODO-entries, with the same file extension as
       normal events: .ics. Many CalDAV servers support synchronizing tasks, vdirsyncer does too.

       todoman is a CLI task manager supporting vdir. Its interface is similar to the ones of Taskwarrior or the
       todo.txt CLI app. You can use filesystem with it.

       Further applications, with missing pages:

       • khal, a CLI calendar application supporting vdir. You can use filesystem with it.

       • Many graphical calendar apps such as dayplanner, Orage or rainlendar save a calendar in a  single  .ics
         file. You can use singlefile with those.

       • khard, a commandline addressbook supporting vdir.  You can use filesystem with it.

       • contactquery.c, a small program explicitly written for querying vdirs from mutt.

       • mates, a commandline addressbook supporting vdir.

       • vdirel, access vdir contacts from Emacs.

   Servers
   Baikal
       Vdirsyncer is continuously tested against the latest version of Baikal.

       • Baikal  up  to  0.2.7  also uses an old version of SabreDAV, with the same issue as ownCloud, see issue
         #160. This issue is fixed in later versions.

   DavMail (Exchange, Outlook)
       DavMail is a proxy program that allows you to use Card- and CalDAV clients with Outlook. That allows  you
       to use vdirsyncer with Outlook.

       In  practice  your  success with DavMail may wildly vary. Depending on your Exchange server you might get
       confronted with weird errors of all sorts (including data-loss).

       Make absolutely sure you use the latest DavMail:

          [storage outlook]
          type = "caldav"
          url = "http://localhost:1080/users/user@example.com/calendar/"
          username = "user@example.com"
          password = ...

       • Older versions of DavMail handle URLs case-insensitively. See issue #144.

       • DavMail is handling malformed data on the Exchange server very  poorly.  In  such  cases  the  Calendar
         Checking Tool for Outlook might help.

       • In some cases, you may see errors about duplicate events. It may look something like this:

            error: my_calendar/calendar: Storage "my_calendar_remote/calendar" contains multiple items with the same UID or even content. Vdirsyncer will now abort the synchronization of this collection, because the fix for this is not clear; It could be the result of a badly behaving server. You can try running:
            error:
            error:     vdirsyncer repair my_calendar_remote/calendar
            error:
            error: But make sure to have a backup of your data in some form. The offending hrefs are:
            [...]

         In order to fix this, you can try the Remove-DuplicateAppointments.ps1 PowerShell script that Microsoft
         has come up with in order to remove duplicates.

   FastMail
       Vdirsyncer is continuously tested against FastMail, thanks to them for providing a free account for  this
       purpose. There are no known issues with it.  FastMail's support pages provide the settings to use:

          [storage cal]
          type = "caldav"
          url = "https://caldav.messagingengine.com/"
          username = ...
          password = ...

          [storage card]
          type = "carddav"
          url = "https://carddav.messagingengine.com/"
          username = ...
          password = ...

   Google
       Using  vdirsyncer  with  Google Calendar is possible as of 0.10, but it is not tested frequently. You can
       use google_contacts and google_calendar.

       For more information see issue #202 and issue #8.

   iCloud
       Vdirsyncer is regularly tested against iCloud.

          [storage cal]
          type = "caldav"
          url = "https://caldav.icloud.com/"
          username = ...
          password = ...

          [storage card]
          type = "carddav"
          url = "https://contacts.icloud.com/"
          username = ...
          password = ...

       Problems:

       • Vdirsyncer can't do two-factor auth with iCloud (there doesn't seem to be a way to do  two-factor  auth
         over the DAV APIs) You'll need to use app-specific passwords instead.

       • iCloud has a few special requirements when creating collections. In principle vdirsyncer can do it, but
         it is recommended to create them from an Apple client (or the iCloud web interface).

         • iCloud requires a minimum length of collection names.

         • Calendars created by vdirsyncer cannot be used as tasklists.

   nextCloud
       Vdirsyncer is continuously tested against the latest version of nextCloud:

          [storage cal]
          type = "caldav"
          url = "https://nextcloud.example.com/"
          username = ...
          password = ...

          [storage card]
          type = "carddav"
          url = "https://nextcloud.example.com/"

       • WebCAL-subscriptions can't be discovered by vdirsyncer. See this relevant issue.

   ownCloud
       Vdirsyncer is continuously tested against the latest version of ownCloud:

          [storage cal]
          type = "caldav"
          url = "https://example.com/remote.php/dav/"
          username = ...
          password = ...

          [storage card]
          type = "carddav"
          url = "https://example.com/remote.php/dav/"
          username = ...
          password = ...

       • Versions older than 7.0.0:  ownCloud  uses  SabreDAV,  which  had  problems  detecting  collisions  and
         race-conditions. The problems were reported and are fixed in SabreDAV's repo, and the corresponding fix
         is also in ownCloud since 7.0.0. See issue #16 for more information.

   Radicale
       Radicale is a very lightweight server, however, it intentionally doesn't implement the CalDAV and CardDAV
       standards  completely,  which  might  lead  to issues even with very well-written clients. Apart from its
       non-conformity with standards, there are multiple other problems with its code quality and the way it  is
       maintained. Consider using e.g. xandikos instead.

       That  said,  vdirsyncer  is  continuously  tested  against the git version and the latest PyPI release of
       Radicale.

       • Vdirsyncer can't create collections on Radicale.

       • Radicale doesn't support time ranges in  the  calendar-query  of  CalDAV,  so  setting  start_date  and
         end_date for caldav will have no or unpredicted consequences.

       • Versions of Radicale older than 0.9b1 choke on RFC-conform queries for all items of a collection.

         You have to set item_types = ["VTODO", "VEVENT"] in caldav for vdirsyncer to work with those versions.

   Xandikos
       Xandikos  is  a  lightweight,  yet  complete  CalDAV  and  CardDAV  server,  backed by git. Vdirsyncer is
       continuously tested against its latest version.

       After running ./bin/xandikos --defaults -d $HOME/dav, you should be able to point vdirsyncer against  the
       root of Xandikos like this:

          [storage cal]
          type = "caldav"
          url = "https://xandikos.example.com/"
          username = ...
          password = ...

          [storage card]
          type = "carddav"
          url = "https://xandikos.example.com/"
          username = ...
          password = ...

KNOWN PROBLEMS

       For any unanswered questions or problems, see contact.

   Requests-related ImportErrors
          ImportError: No module named packages.urllib3.poolmanager

          ImportError: cannot import name iter_field_objects

       Debian  and  nowadays  even other distros make modifications to the requests package that don't play well
       with packages assuming a normal requests. This is due to stubbornness on both sides.

       See issue #82 and issue #140 for past discussions. You have one option to work around this, that  is,  to
       install vdirsyncer in a virtualenv, see manual-installation.

CONTRIBUTING TO THIS PROJECT

       NOTE:

          • Please read contact for questions and support requests.

          • All participants must follow the pimutils Code of Conduct.

   The issue tracker
       We use GitHub issues for organizing bug reports and feature requests.

       The following labels are of interest:

       • "Planning" is for issues that are still undecided, but where at least some discussion exists.

       • "Blocked"  is  for  issues  that  can't  be worked on at the moment because some other unsolved problem
         exists. This problem may be a bug in some software dependency, for instance.

       • "Ready" contains issues that are ready to work on.

       If you just want to get started with contributing, the "ready" issues are  an  option.  Issues  that  are
       still  in  "Planning"  are  also  an  option,  but  require  more upfront thinking and may turn out to be
       impossible to solve, or at least harder than anticipated. On the flip side those  tend  to  be  the  more
       interesting issues as well, depending on how one looks at it.

       All  of  those labels are also available as a kanban board on waffle.io. It is really just an alternative
       overview over all issues, but might be easier to comprehend.

       Feel free to contact me or comment on the relevant issues for further information.

   Reporting bugs
       • Make sure your problem isn't already listed in problems.

       • Make sure you have the absolutely latest version of vdirsyncer. For users of some  Linux  distributions
         such  as  Debian  or  Fedora this may not be the version that your distro offers. In those cases please
         file a bug against the distro package, not against upstream vdirsyncer.

       • Use --verbosity=DEBUG when including output from vdirsyncer.

   Suggesting features
       If you're suggesting a feature, keep in mind that vdirsyncer tries not to be a full calendar or  contacts
       client,  but  rather  just  the  piece  of  software  that  synchronizes all the data. Take a look at the
       documentation for software working with vdirsyncer.

   Submitting patches, pull requestsDiscuss everything in the issue tracker first (or contact me somehow else) before implementing it.

       • Make sure the tests pass. See below for running them.

       • But not because you wrote too few tests.

       • Add yourself to AUTHORS.rst, and add a note to CHANGELOG.rst too.

   Running tests, how to set up your development environment
       For many patches, it might suffice to just let Travis run the tests. However,  Travis  is  slow,  so  you
       might want to run them locally too. For this, set up a virtualenv and run this inside of it:

          # install:
          #  - vdirsyncer from the repo into the virtualenv
          #  - stylecheckers (flake8) and code formatters (autopep8)
          make install-dev

          # Install git commit hook for the stylechecker
          make install-git-hooks

          # install test dependencies
          make install-test

       Then you can run:

          make test   # The normal testsuite
          make style  # Stylechecker
          make docs   # Build the HTML docs, output is at docs/_build/html/

       The  Makefile  has  a lot of options that allow you to control which tests are run, and which servers are
       tested. Take a look at its code where they are all initialized and documented.

       For example, to test xandikos, run:

          make DAV_SERVER=xandikos install-test
          make DAV_SERVER=xandikos test

       If you have any questions, feel free to open issues about it.

   Structure of the testsuite
       Within tests/, there are three main folders:

       • system contains system- and also integration tests. A rough rule is: If the  test  is  using  temporary
         files, put it here.

       • unit, where each testcase tests a single class or function.

       • storage runs a generic storage testsuite against all storages.

       The  reason  for  this  separation  is: We are planning to generate separate coverage reports for each of
       those testsuites. Ideally unit would generate palatable coverage of the entire codebase on its  own,  and
       the combination of system and storage as well.

THE VDIR STORAGE FORMAT

       This document describes a standard for storing calendars and contacts on a filesystem, with the main goal
       of being easy to implement.

       Vdirsyncer synchronizes to vdirs via filesystem. Each vdir (basically just a directory with some files in
       it) represents a calendar or addressbook.

   Basic Structure
       The main folder (root) contains an arbitrary number of subfolders (collections), which contain only files
       (items). Synonyms for "collection" may be "addressbook" or "calendar".

       An item is:

       • A vCard file, in which case the file extension must be .vcf, or

       • An iCalendar file, in which case the file extension must be .ics.

       An item should contain a UID property as described by the vCard and iCalendar standards. If  it  contains
       more than one UID property, the values of those must not differ.

       The  file  must  contain  exactly  one  event,  task or contact. In most cases this also implies only one
       VEVENT/VTODO/VCARD component per file, but e.g.  recurrence  exceptions  would  require  multiple  VEVENT
       components per event.

       The  filename  should  have  similar  properties  as  the  UID of the file content.  However, there is no
       requirement for these two to be the same. Programs may  choose  to  store  additional  metadata  in  that
       filename,  however,  at  the  same  time  they  must  not  assume that the metadata they included will be
       preserved by other programs.

   Metadata
       Any of the below metadata files may be absent. None of the files listed below have any file extensions.

       • A file called color inside the vdir indicates the vdir's color, a property that is only relevant in  UI
         design.

         Its  content  is  an  ASCII-encoded  hex-RGB  value of the form #RRGGBB. For example, a file content of
         #FF0000 indicates that the vdir has a red (user-visible) color. No short forms or informal values  such
         as red (as known from CSS, for example) are allowed. The prefixing # must be present.

       • A file called displayname contains a UTF-8 encoded label that may be used to represent the vdir in UIs.

   Writing to vdirs
       Creating and modifying items or metadata files should happen atomically.

       Writing  to  a temporary file on the same physical device, and then moving it to the appropriate location
       is usually a very effective solution. For this purpose, files with the  extension  .tmp  may  be  created
       inside collections.

       When changing an item, the original filename must be used.

   Reading from vdirs
       • Any file ending with the .tmp or no file extension must not be treated as an item.

       • The ident part of the filename should not be parsed to improve the speed of item lookup.

   Considerations
       The  primary  reason  this  format  was  chosen  is  due to its compatibility with the CardDAV and CalDAV
       standards.

   Performance
       Currently, vdirs suffer from a rather major performance problem, one which current implementations try to
       mitigate by building up indices of the collections for faster search and lookup.

       The  reason  items'  filenames  don't  contain  any  extra information is simple: The solutions presented
       induced duplication of data, where one duplicate might become out of date because of bad implementations.
       As it stands right now, a index format could be formalized separately though.

       vdirsyncer  doesn't  really  have  to  bother  about  efficient  item lookup, because its synchronization
       algorithm needs to fetch the whole list of items anyway.  Detecting  changes  is  easily  implemented  by
       checking the files' modification time.

PACKAGING GUIDELINES

       Thank  you  very  much  for  packaging vdirsyncer! The following guidelines should help you to avoid some
       common pitfalls.

       While they are called guidelines and therefore theoretically not  mandatory,  if  you  consider  going  a
       different  direction,  please  first  open  an issue or contact me otherwise instead of just going ahead.
       These guidelines exist for my own convenience too.

   Obtaining the source code
       The main distribution channel is PyPI, and source tarballs can be obtained there. Do  not  use  the  ones
       from GitHub: Their tarballs contain useless junk and are more of a distraction than anything else.

       I  give each release a tag in the git repo. If you want to get notified of new releases, GitHub's feed is
       a good way.

   Dependency versions
       As with most Python  packages,  setup.py  denotes  the  dependencies  of  vdirsyncer.  It  also  contains
       lower-bound versions of each dependency. Older versions will be rejected by the testsuite.

   Testing
       Everything  testing-related  goes  through  the  Makefile  in the root of the repository or PyPI package.
       Trying to e.g. run py.test directly  will  require  a  lot  of  environment  variables  to  be  set  (for
       configuration) and you probably don't want to deal with that.

       You can install the testing dependencies with:

          make install-test

       You  probably  don't  want this since it will use pip to download the dependencies. Alternatively you can
       find the testing dependencies in test-requirements.txt, again with lower-bound version requirements.

       You also have to have vdirsyncer fully installed at this point. Merely cd-ing into the tarball  will  not
       be sufficient.

       Running the tests happens with:

          make test

       Hypothesis  will  randomly  generate  test  input.  If  you  care  about  deterministic  tests,  set  the
       DETERMINISTIC_TESTS variable to "true":

          make DETERMINISTIC_TESTS=true test

       There are a lot of additional variables that allow you to test vdirsyncer against  a  particular  server.
       Those  variables are not "stable" and may change drastically between minor versions. Just don't use them,
       you are unlikely to find bugs that vdirsyncer's CI hasn't found.

   Documentation
       Using Sphinx you can generate the documentation you're reading right now in a variety of formats, such as
       HTML, PDF, or even as a manpage. That said, I only take care of the HTML docs' formatting.

       You  can  find  a  list  of dependencies in docs-requirements.txt. Again, you can install those using pip
       with:

          make install-docs

       Then change into the docs/ directory and build whatever format you want using the Makefile in there  (run
       make for the formats you can build).

   Contrib files
       Reference systemd.service and systemd.timer unit files are provided. It is recommended to install this if
       your distribution is systemd-based.

SUPPORT AND CONTACT

       • The #pimutils IRC channel on Freenode might be active, depending on your timezone. Use it  for  support
         and general (including off-topic) discussion.

       • Open a GitHub issue for concrete bug reports and feature requests.

       • Lastly, you can also contact the author directly. Do this for security issues. If that doesn't work out
         (i.e. if I don't respond within one week), use contact@pimutils.org.

CHANGELOG

       This changelog only contains information that might be useful to end users and package  maintainers.  For
       further info, see the git commit log.

       Package  maintainers  and  users  who have to manually update their installation may want to subscribe to
       GitHub's tag feed.

   Version 0.16.7
       released on July 19

       • Fixes for Python 3.7

   Version 0.16.6
       released on 13 June 2018Packagers: Documentation building no longer needs a working installation of vdirsyncer.

   Version 0.16.5
       released on 13 June 2018Packagers: click-log 0.3 is required.

       • All output will now happen on stderr (because of the upgrade of click-log).

   Version 0.16.4
       released on 05 February 2018

       • Fix tests for new Hypothesis version. (Literally no other change included)

   Version 0.16.3
       released on 03 October 2017

       • First version with custom Debian and Ubuntu packages. See issue #663.

       • Remove invalid ASCII control characters from server responses. See issue #626.

       • packagers: Python 3.3 is no longer supported. See pull request #674.

   Version 0.16.2
       released on 24 August 2017

       • Fix crash when using daterange or item_type filters in google_calendar, see issue #657.

       • Packagers: Fixes for new version 0.2.0 of  click-log.  The  version  requirements  for  the  dependency
         click-log changed.

   Version 0.16.1
       released on 8 August 2017

       • Removed remoteStorage support, see issue #647.

       • Fixed test failures caused by latest requests version, see issue #660.

   Version 0.16.0
       released on 2 June 2017

       • Strip METHOD:PUBLISH added by some calendar providers, see issue #502.

       • Fix crash of Google storages when saving token file.

       • Make DAV discovery more RFC-conformant, see pull request #585.

       • Vdirsyncer is now tested against Xandikos, see pull request #601.

       • Subfolders  with  a  leading  dot are now ignored during discover for filesystem storage. This makes it
         easier to combine it with version control.

       • Statuses are now stored in a sqlite database. Old data is automatically  migrated.  Users  with  really
         large  datasets  should encounter performance improvements. This means that sqlite3 is now a dependency
         of vdirsyncer.

       • Vdirsyncer is now licensed under the 3-clause BSD license, see issue #610.

       • Vdirsyncer now includes experimental support for EteSync, see pull request #614.

       • Vdirsyncer now uses more filesystem metadata for determining whether an item changed. You will notice a
         possibly heavy CPU/IO spike on the first sync after upgrading.

       • Packagers:  Reference  systemd.service  and systemd.timer unit files are provided. It is recommended to
         install these as documentation if your distribution is systemd-based.

   Version 0.15.0
       released on 28 February 2017

       • Deprecated syntax for configuration values is now completely rejected. All values now have to be  valid
         JSON.

       • A few UX improvements for Google storages, see issue #549 and issue #552.

       • Fix collection discovery for google_contacts, see issue #564.

       • iCloud is now tested on Travis, see issue #567.

   Version 0.14.1
       released on 05 January 2017vdirsyncer  repair no longer changes "unsafe" UIDs by default, an extra option has to be specified. See
         issue #527.

       • A lot of important documentation updates.

   Version 0.14.0
       released on 26 October 2016vdirsyncer sync now continues other uploads if one upload failed.  The exit code in such situations  is
         still non-zero.

       • Add partial_sync option to pair section. See the config docs.

       • Vdirsyner  will  now warn if there's a string without quotes in your config.  Please file issues if you
         find documentation that uses unquoted strings.

       • Fix an issue that would break khal's config setup wizard.

   Version 0.13.1
       released on 30 September 2016

       • Fix a bug that would completely break collection discovery.

   Version 0.13.0
       released on 29 September 2016

       • Python 2 is no longer supported at all. See issue #219.

       • Config sections are now checked for duplicate names. This also means that you  cannot  have  a  storage
         section  [storage foo] and a pair [pair foo] in your config, they have to have different names. This is
         done such that console output is always unambiguous. See issue #459.

       • Custom commands can now be used for conflict resolution during sync. See issue #127.

       • http now completely ignores UIDs. This avoids a lot of unnecessary down- and uploads.

   Version 0.12.1
       released on 20 August 2016

       • Fix a crash for Google and DAV storages. See pull request #492.

       • Fix an URL-encoding problem with DavMail. See issue #491.

   Version 0.12
       released on 19 August 2016singlefile now supports collections. See pull request #488.

   Version 0.11.3
       released on 29 July 2016

       • Default value of auth parameter was changed from guess to  basic  to  resolve  issues  with  the  Apple
         Calendar Server (issue #457) and improve performance. See issue #461.

       • Packagers: The click-threading requirement is now >=0.2. It was incorrect before. See issue #478.

       • Fix  a  bug  in  the  DAV XML parsing code that would make vdirsyncer crash on certain input. See issue
         #480.

       • Redirect chains should now be properly handled when resolving well-known URLs. See pull request #481.

   Version 0.11.2
       released on 15 June 2016

       • Fix typo that would break tests.

   Version 0.11.1
       released on 15 June 2016

       • Fix a bug in collection validation.

       • Fix a cosmetic bug in debug output.

       • Various documentation improvements.

   Version 0.11.0
       released on 19 May 2016

       • Discovery is no longer automatically done when running vdirsyncer sync.  vdirsyncer discover now has to
         be explicitly called.

       • Add a .plist example for Mac OS X.

       • Usage under Python 2 now requires a special config parameter to be set.

       • Various  deprecated  configuration  parameters do no longer have specialized errormessages. The generic
         error message for unknown parameters is shown.

         • Vdirsyncer no longer warns that the passwordeval parameter has been renamed to password_command.

         • The keyring fetching strategy has been dropped some versions ago, but the specialized  error  message
           has been dropped.

         • An  old  status format from version 0.4 is no longer supported. If you're experiencing problems, just
           delete your status folder.

   Version 0.10.0
       released on 23 April 2016

       • New storage types google_calendar and google_contacts have been added.

       • New global command line option --config, to specify an alternative config file. See issue #409.

       • The collections parameter can now be used to synchronize differently-named collections with each other.

       • Packagers: The lxml dependency has been dropped.

       • XML parsing is now a lot stricter. Malfunctioning servers that used to work with  vdirsyncer  may  stop
         working.

   Version 0.9.3
       released on 22 March 2016singlefile and http now handle recurring events properly.

       • Fix a typo in the packaging guidelines.

       • Moved  to  pimutils  organization on GitHub. Old links should redirect, but be aware of client software
         that doesn't properly handle redirects.

   Version 0.9.2
       released on 13 March 2016

       • Fixed testsuite for environments that don't have any web browser installed.  See pull request #384.

   Version 0.9.1
       released on 13 March 2016

       • Removed    leftover    debug    print    statement    in    vdirsyncer     discover,     see     commit
         3d856749f37639821b148238ef35f1acba82db36.

       • metasync will now strip whitespace from the start and the end of the values. See issue #358.

       • New Packaging Guidelines have been added to the documentation.

   Version 0.9.0
       released on 15 February 2016

       • The  collections parameter is now required in pair configurations.  Vdirsyncer will tell you what to do
         in its error message. See issue #328.

   Version 0.8.1
       released on 30 January 2016

       • Fix error messages when invalid parameter fetching strategy is used. This is  important  because  users
         would receive awkward errors for using deprecated keyring fetching.

   Version 0.8.0
       released on 27 January 2016

       • Keyring  support  has  been  removed,  which  means  that  password.fetch  = ["keyring", "example.com",
         "myuser"] doesn't work anymore.

         For existing setups: Use  password.fetch  =  ["command",  "keyring",  "get",  "example.com",  "myuser"]
         instead, which is more generic. See the documentation for details.

       • Now emitting a warning when running under Python 2. See issue #219.

   Version 0.7.5
       released on 23 December 2015

       • Fixed a bug in remotestorage that would try to open a CLI browser for OAuth.

       • Fix a packaging bug that would prevent vdirsyncer from working with newer lxml versions.

   Version 0.7.4
       released on 22 December 2015

       • Improved error messages instead of faulty server behavior, see issue #290 and issue #300.

       • Safer shutdown of threadpool, avoid exceptions, see issue #291.

       • Fix a sync bug for read-only storages see commit ed22764921b2e5bf6a934cf14aa9c5fede804d8e.

       • Etag  changes  are  no  longer  sufficient to trigger sync operations. An actual content change is also
         necessary. See issue #257.

       • remotestorage now automatically opens authentication dialogs in your configured GUI browser.

       • Packagers: lxml>=3.1 is now required (newer lower-bound version).

   Version 0.7.3
       released on 05 November 2015

       • Make remotestorage-dependencies actually optional.

   Version 0.7.2
       released on 05 November 2015

       • Un-break testsuite.

   Version 0.7.1
       released on 05 November 2015Packagers: The setuptools extras keyring and remotestorage have been added. They're basically  optional
         dependencies. See setup.py for more details.

       • Highly  experimental  remoteStorage  support  has  been  added. It may be completely overhauled or even
         removed in any version.

       • Removed mentions of old password_command in documentation.

   Version 0.7.0
       released on 27 October 2015Packagers: New dependencies are click_threading, click_log and click>=5.0.

       • password_command is gone. Keyring support got completely overhauled. See keyring.

   Version 0.6.0
       released on 06 August 2015password_command invocations with non-zero exit code are now fatal  (and  will  abort  synchronization)
         instead of just producing a warning.

       • Vdirsyncer  is  now able to synchronize metadata of collections. Set metadata = ["displayname"] and run
         vdirsyncer metasync.

       • Packagers: Don't use the GitHub tarballs, but the PyPI ones.

       • Packagers: build.sh is gone, and Makefile is included in tarballs. See the content of Makefile  on  how
         to run tests post-packaging.

       • verify_fingerprint doesn't automatically disable verify anymore.

   Version 0.5.2
       released on 15 June 2015

       • Vdirsyncer now checks and corrects the permissions of status files.

       • Vdirsyncer is now more robust towards changing UIDs inside items.

       • Vdirsyncer  is  now handling unicode hrefs and UIDs correctly. Software that produces non-ASCII UIDs is
         broken, but apparently it exists.

   Version 0.5.1
       released on 29 May 2015N.b.: The PyPI upload of 0.5.0 is completely broken.

       • Raise version of required requests-toolbelt to 0.4.0.

       • Command line should be a lot faster when no work is done, e.g. for help output.

       • Fix compatibility with iCloud again.

       • Use only one worker if debug mode is activated.

       • verify=false is now disallowed in vdirsyncer, please use verify_fingerprint instead.

       • Fixed a bug where vdirsyncer's DAV storage was  not  using  the  configured  useragent  for  collection
         discovery.

   Version 0.4.4
       released on 12 March 2015

       • Support for client certificates via the new auth_cert parameter, see issue #182 and pull request #183.

       • The icalendar package is no longer required.

       • Several bugfixes related to collection creation.

   Version 0.4.3
       released on 20 February 2015

       • More performance improvements to singlefile-storage.

       • Add post_hook param to filesystem-storage.

       • Collection creation now also works with SabreDAV-based servers, such as Baikal or ownCloud.

       • Removed some workarounds for Radicale. Upgrading to the latest Radicale will fix the issues.

       • Fixed issues with iCloud discovery.

       • Vdirsyncer now includes a simple repair command that seeks to fix some broken items.

   Version 0.4.2
       released on 30 January 2015

       • Vdirsyncer now respects redirects when uploading and updating items. This might fix issues with Zimbra.

       • Relative status_path values are now interpreted as relative to the configuration file's directory.

       • Fixed compatibility with custom SabreDAV servers. See issue #166.

       • Catch harmless threading exceptions that occur when shutting down vdirsyncer.  See issue #167.

       • Vdirsyncer now depends on atomicwrites.

       • Massive performance improvements to singlefile-storage.

       • Items with extremely long UIDs should now be saved properly in filesystem-storage. See issue #173.

   Version 0.4.1
       released on 05 January 2015

       • All  create  arguments  from  all  storages  are  gone.  Vdirsyncer now asks if it should try to create
         collections.

       • The old config values True, False, on, off and None are now invalid.

       • UID conflicts are now properly handled instead of ignoring one  item.  Card-  and  CalDAV  servers  are
         already supposed to take care of those though.

       • Official Baikal support added.

   Version 0.4.0
       released on 31 December 2014

       • The passwordeval parameter has been renamed to password_command.

       • The old way of writing certain config values such as lists is now gone.

       • Collection  discovery  has  been  rewritten.  Old configuration files should be compatible with it, but
         vdirsyncer now caches the results of the collection discovery. You have to run vdirsyncer  discover  if
         collections were added or removed on one side.

       • Pair  and  storage  names are now restricted to certain characters. Vdirsyncer will issue a clear error
         message if your configuration file is invalid in that regard.

       • Vdirsyncer now supports the XDG-Basedir specification. If the  VDIRSYNCER_CONFIG  environment  variable
         isn't  set  and the ~/.vdirsyncer/config file doesn't exist, it will look for the configuration file at
         $XDG_CONFIG_HOME/vdirsyncer/config.

       • Some improvements to CardDAV and CalDAV discovery, based on problems found with FastMail.  Support  for
         .well-known-URIs has been added.

   Version 0.3.4
       released on 8 December 2014

       • Some more bugfixes to config handling.

   Version 0.3.3
       released on 8 December 2014

       • Vdirsyncer now also works with iCloud. Particularly collection discovery and etag handling were fixed.

       • Vdirsyncer now encodes Cal- and CardDAV requests differently. This hasn't been well-tested with servers
         like Zimbra or SoGo, but isn't expected to cause any problems.

       • Vdirsyncer is now more robust regarding invalid responses from CalDAV servers. This  should  help  with
         future compatibility with Davmail/Outlook.

       • Fix a bug when specifying item_types of caldav in the deprecated config format.

       • Fix  a bug where vdirsyncer would ignore all but one character specified in unsafe_href_chars of caldav
         and carddav.

   Version 0.3.2
       released on 3 December 2014

       • The current config format has been deprecated, and support for it will be  removed  in  version  0.4.0.
         Vdirsyncer warns about this now.

   Version 0.3.1
       released on 24 November 2014

       • Fixed  a  bug  where vdirsyncer would delete items if they're deleted on side A but modified on side B.
         Instead vdirsyncer will now upload the new items to side A. See issue #128.

       • Synchronization continues with the remaining pairs if one pair crashes, see issue #121.

       • The processes config key is gone. There is now a --max-workers option on the CLI which  has  a  similar
         purpose. See pull request #126.

       • The  Read  The  Docs-theme  is  no  longer  required for building the docs. If it is not installed, the
         default theme will be used. See issue #134.

   Version 0.3.0
       released on 20 September 2014

       • Add verify_fingerprint parameter to http, caldav and carddav, see issue #99 and pull request #106.

       • Add passwordeval parameter to general_config, see issue #108 and pull request #117.

       • Emit warnings (instead of exceptions) about certain invalid responses from the server, see issue  #113.
         This is apparently required for compatibility with Davmail.

   Version 0.2.5
       released on 27 August 2014

       • Don't  ask for the password of one server more than once and fix multiple concurrency issues, see issue
         #101.

       • Better validation of DAV endpoints.

   Version 0.2.4
       released on 18 August 2014

       • Include workaround for collection discovery with latest version of Radicale.

       • Include metadata files such as the changelog or license in source distribution, see issue #97 and issue
         #98.

   Version 0.2.3
       released on 11 August 2014

       • Vdirsyncer now has a --version flag, see issue #92.

       • Fix a lot of bugs related to special characters in URLs, see issue #49.

   Version 0.2.2
       released on 04 August 2014

       • Remove  a  security check that caused problems with special characters in DAV URLs and certain servers.
         On top of that, the security check was nonsensical.  See issue #87 and issue #91.

       • Change some errors to warnings, see issue #88.

       • Improve collection autodiscovery for servers without full support.

   Version 0.2.1
       released on 05 July 2014

       • Fix bug where vdirsyncer shows empty addressbooks when using CardDAV with Zimbra.

       • Fix infinite loop when password doesn't exist in system keyring.

       • Colorized errors, warnings and debug messages.

       • vdirsyncer now depends on the click package instead of argvard.

   Version 0.2.0
       released on 12 June 2014

       • vdirsyncer now depends on the icalendar package from PyPI, to get rid of its own broken parser.

       • vdirsyncer now also depends on requests_toolbelt. This makes it possible to  guess  the  authentication
         type instead of blankly assuming basic.

       • Fix  a  semi-bug  in  caldav and carddav storages where a tuple (href, etag) instead of the proper etag
         would have been returned from  the  upload  method.   vdirsyncer  might  do  unnecessary  copying  when
         upgrading to this version.

       • Add the storage singlefile. See issue #48.

       • The  collections  parameter  for  pair  sections  now  accepts the special values from a and from b for
         automatically discovering collections.  See pair_config.

       • The read_only parameter was added to storage sections. See storage_config.

   Version 0.1.5
       released on 14 May 2014

       • Introduced changelogs

       • Many bugfixes

       • Many doc fixes

       • vdirsyncer now doesn't necessarily need UIDs anymore for synchronization.

       • vdirsyncer now aborts if one collection got completely emptied between synchronizations. See issue #42.

CREDITS AND LICENSE

   Contributors
       In alphabetical order:

       • Ben Boeckel

       • Christian Geier

       • Clément Mondon

       • Hugo Osvaldo Barrera

       • Julian Mehne

       • Malte Kiefer

       • Marek Marczykowski-Górecki

       • Markus Unterwaditzer

       • Michael Adler

       • Thomas Weißschuh

       Additionally FastMail sponsored a paid account for testing. Thanks!

   License

DONATIONS

       If you found my work useful, please consider donating. Thank you!

       • Bitcoin: 16sSHxZm263WHR9P9PJjCxp64jp9ooXKVtPayPal.meBountysource is useful for funding work on a specific GitHub issue.

         • There's also Bountysource Salt, for one-time and recurring donations.

         • Donations via Bountysource are publicly listed. Use PayPal if you dislike that.

       • Flattr or Gratipay can be used for recurring donations.

AUTHOR

       Markus Unterwaditzer

COPYRIGHT

       2014-2019, Markus Unterwaditzer & contributors