Provided by: imapfilter_2.5.2-2_amd64 
NAME
imapfilter_config — imapfilter configuration file
SYNOPSIS
$HOME/.imapfilter/config.lua
DESCRIPTION
imapfilter(1) uses the Lua programming language as a configuration and extension language,
therefore the configuration file is a Lua script.
Although knowledge of Lua is not required to use imapfilter(1), it is nonetheless
recommended, especially if one wants to extend it.
CONVENTIONS
A brief description of the Lua values and types mentioned hereafter in the manual page
follows:
The nil is the type of the value “nil”, whose main property is to be different from any
other value; usually it represents the absence of a useful value.
The boolean is the type of the values “true” and “false”. Both “nil” and “false” make a
condition false; any other value makes it true.
The type number represents real numbers.
The type string represents a sequence of characters and can be defined using single
quotes, double quotes or double square brackets.
The type table implements associative arrays, that is, arrays that can be indexed not
only with numbers, but with any value.
A function is a first-class value; it can be stored in variables, passed as argument to
other functions, and returned as a result.
OPTIONS
Program's options are set using an already initialised table named “options”, in the
following manner:
options.timeout = 120
options.namespace = false
options.charset = 'ISO-8859-1'
Available options are:
cache When this option is enabled, parts of messages are cached locally in memory to avoid
being downloaded more than once. The cache is preserved for the current session
only. This variable takes a boolean as a value. Default is “true”.
certificates
When this option is enabled, the server certificate can be accepted and stored, in
order to validate the authenticity of the server in future connections. This
variable takes a boolean as a value. Default is “true”.
charset
Indicates to the server the character set of the strings for the searching methods.
This variable takes a string as a value. By default no character set is set, and
thus plain ASCII should be assumed by the server.
create According to the IMAP specification, when trying to write a message to a non-
existent mailbox, the server must send a hint to the client, whether it should
create the mailbox and try again or not. However some IMAP servers don't follow the
specification and don't send the correct response code to the client. By enabling
this option the client tries to create the mailbox, despite of the server's
response. This variable takes a boolean as a value. Default is “false”.
close This option controls whether the currently selected mailbox is implicitly closed at
the end of each performed operation, thus removing all messages that are marked
deleted. This variable takes a boolean as a value. Default is “false”.
crammd5
When this option is enabled and the server supports the Challenge-Response
Authentication Mechanism (specifically CRAM-MD5), this method will be used for user
authentication instead of a plaintext password LOGIN. This variable takes a boolean
as a value. Default is “true”.
expunge
Normally, messages are marked for deletion and are actually deleted when the mailbox
is closed. When this option is enabled, messages are expunged immediately after
being marked deleted. This variable takes a boolean as a value. Default is “true”.
info When this options is enabled, a summary of the program's actions is printed, while
processing mailboxes. This variable takes a boolean as a value. Default is “true”.
keepalive
The time in minutes before terminating and re-issuing the IDLE command, in order to
keep alive the connection, by resetting the inactivity timeout of the server. A
standards compliant server must have an inactivity timeout of at least 30 minutes.
But it may happen that some IMAP servers don't respect that, or some intermediary
network device has a shorter timeout. By setting this option the above problem can
be worked around. This variable takes a number as a value. Default is “29” minutes.
namespace
When enabled, the program gets the namespace of the user's personal mailboxes, and
applies automatically the prefix and hierarchy delimiter to any mailboxes residing
on the mail server; the user must use the ‘/’ character as the delimiter and “” (ie.
nothing) as the prefix, regardless of the folder format of the mail server. This
must be disabled, if the user wants to manually specify mailbox names (eg. because
they are not part of the user's personal namespace mailboxes). This variable takes
boolean as a value. Default is “true”.
recover
With this option it is possible to control the recovery functionality, which
restores a session (the connection to the server and the IMAP state at the time),
after some unexpected event takes place. Currently there are two types of events
that can close abnormally a session, and finally cause the program to terminate:
network errors, and the IMAP BYE response which a server can send anytime. When
this option is set to “all” the recovery function is triggered by both types of
events, when set to “errors” only in the case of network errors, and when set to
“none” the mechanism is completely disabled. Default is “all”.
starttls
When this option is enabled and the server supports the IMAP STARTTLS extension, a
TLS connection will be negotiated with the mail server in the beginning of the
session. This variable takes a boolean as value. Default is “true”.
subscribe
By enabling this option new mailboxes that were automatically created, get also
subscribed; they are set active in order for IMAP clients to recognize them. This
variable takes a boolean as a value. Default is “false”.
timeout
The time in seconds for the program to wait for a mail server's response. If not
set, the client will block indefinitely. This variable takes a number as a value.
Default is “60” seconds.
ACCOUNTS
Accounts are initialized using the IMAP() function, and the details of the connection are
defined using an account table:
myaccount = IMAP {
server = 'imap.mail.server',
username = 'me',
password = 'secret',
ssl = 'ssl3'
}
An account table must have the following elements:
server The hostname of the IMAP server to connect to. It takes a string as a value.
username
User's name. It takes a string as a value.
An account table can also have the following optional elements:
password
User's secret keyword. If a password wasn't supplied the user will be asked to
enter one interactively the first time it will be needed. It takes a string as a
value.
port The port to connect to. It takes a number as a value. Default is “143” for imap
and “993” for imaps.
ssl Forces an imaps connection and specifies the SSL/TLS protocol to be used. It takes
a string as a value, specifically one of: “ssl2”, “ssl3”, “tls1”.
LISTING
The following methods can be used on an account to list mailboxes in a folder of an account:
list_all(folder)
Lists all the available mailboxes in the folder (string), and returns a table that
contains strings, the available mailboxes, and a table that contains strings, the
available folders.
list_subscribed(folder)
Lists all the subscribed mailboxes in the folder (string), and returns a table that
contains strings, the subscribed mailboxes, and a table that contains strings, the
subscribed folders.
The following methods can be used on an account to list mailboxes, using wildcards, in a
folder of an account. The ‘*’ wildcard, matches any character and the ‘%’ matches any
character except the folder delimiter, ie. non-recursively:
list_all(folder, mailbox)
Lists all the available mailboxes in the folder (string) with the name mailbox
(string), and returns a table that contains strings, the available mailboxes, and a
table that contains strings, the available folders. Wildcards may only be used in
the mailbox argument.
list_subscribed(folder, mailbox)
Lists all the subscribed mailboxes in the folder (string) with the name mailbox
(string), and returns a table that contains strings, the subscribed mailboxes, and a
table that contains strings, the subscribed folders. Wildcards may only be used in
the mailbox argument.
Examples:
mailboxes, folders = myaccount:list_subscribed('myfolder')
mailboxes, folders = myaccount:list_all('myfolder/mysubfolder', '*')
MANIPULATING
The following methods can be used to manipulate mailboxes in an account:
create_mailbox(name)
Creates the name (string) mailbox.
delete_mailbox(name)
Deletes the name (string) mailbox.
rename_mailbox(oldname, newname)
Renames the oldname (string) mailbox to newname (string).
subscribe_mailbox(name)
Subscribes the name (string) mailbox.
unsubscribe_mailbox(name)
Unsubscribes the name (string) mailbox.
Examples:
myaccount:create_mailbox('mymailbox')
myaccount:subscribe_mailbox('mymailbox')
myaccount:unsubscribe_mailbox('myfolder/mymailbox')
myaccount:delete_mailbox('myfolder/mymailbox')
MAILBOXES
After an IMAP account has been initialized, mailboxes residing in that account can be
accessed simply as elements of the account table:
myaccount.mymailbox
If mailbox names don't only include letters, digits and underscores, or begin with a digit,
an alternative form must be used:
myaccount['mymailbox']
A mailbox inside a folder can be only accessed by using the alternative form:
myaccount['myfolder/mymailbox']
The methods that are available for an account (eg. list_all(), create_mailbox(), etc.) ,
are considered keywords and must not be used as mailbox names, and the same also applies for
any string starting with an underscore, as they are considered reserved.
CHECKING
The following methods can be used to check the status of a mailbox:
check_status()
The check_status() method gets the current status of a mailbox, and returns four
values of number type: the total number of messages, the number of recent messages,
the number of unseen messages in the mailbox, and the next UID to be assigned to a
new message in the mailbox.
enter_idle()
The enter_idle() method implements the IMAP IDLE (RFC 2177) extension. By using
this extension it's not necessary to poll the server for changes to the selected
mailbox (ie. using the check_status() method), but instead the server sends an
update when there is a change in the mailbox (eg. in case of new mail). When the
enter_idle() method has been called no more commands in the configuration file are
executed until an update is received, at which point the enter_idle() method
returns. For the enter_idle() to work, the IDLE extension has to be supported by
the IMAP server. The enter_idle() method returns one value of type boolean: “true”
if the IDLE extension is supported and there was a update in the mailbox, and
“false” if the IDLE extension is not supported, in which case the method returns
immediately.
Examples:
exist, unread, unseen, uidnext = myaccount.mymailbox:check_status()
update = myaccount.mymailbox:enter_idle()
SEARCHING
The searching methods in this subsection can be applied to any mailbox. They return a
special form of table, that contains the messages that match the searching method. This
table can be combined with other tables using logic theory. There are three available
operations, that implement logical “or”, logical “and” and logical “not”.
The logical “or” is implemented using the ‘+’ operator:
results = myaccount.mymailbox:is_unseen() +
myaccount.mymailbox:is_larger(100000)
The logical “and” is implemented using the ‘*’ operator:
results = myaccount.mymailbox:is_unseen() *
myaccount.mymailbox:is_larger(100000)
The logical “not” is implemented using the ‘-’ operator:
results = myaccount.mymailbox:is_unseen() -
myaccount.mymailbox:is_larger(100000)
The three logical operators can be combined in the same expression. The logical “and” has
higher precedence than the logical “or” and the logical “not”, with the latter two having
the same precedence, and parentheses may be used to change this behaviour:
results = myaccount.mymailbox:is_unseen() +
myaccount.mymailbox:is_larger(100000) *
myaccount.mymailbox:contain_subject('test')
results = ( myaccount.mymailbox:is_unseen() +
myaccount.mymailbox:is_larger(100000) ) *
myaccount.mymailbox:contain_subject('test')
The returned tables of the searching methods can also be stored in variables and then
further processed:
unseen = myaccount.myaccount:is_unseen()
larger = myaccount.mymailbox:is_larger(100000)
subject = myaccount.mymailbox:contain_subject('test')
results = unseen + larger * subject
A composite filter that includes one or more simple rules can be defined:
myfilter = function ()
return myaccount.mymailbox:is_unseen() +
myaccount.mymailbox:is_larger(100000) *
myaccount.mymailbox:contain_subject('test')
end
results = myfilter()
Composite filters can may be more dynamic by adding arguments:
myfilter = function (mailbox, size, subject)
return mailbox:is_unseen() +
mailbox:is_larger(size) *
mailbox:contain_subject(subject)
end
results = myfilter(myaccount.mailbox, 100000, 'test')
It is also possible to combine the searching methods in different mailboxes, either at the
same or different accounts, for example when the same actions will be executed on messages
residing in different mailboxes or accounts.
results = myaccount.mymailbox:is_unseen() +
myaccount.myothermailbox:is_larger(100000) +
myotheraccount.myothermailbox:contain_subject('test')
The following method can be used to get all messages in a mailbox:
select_all()
All messages.
The following methods can be used to search for messages that are in a specific state:
is_answered()
Messages that have been answered.
is_deleted()
Messages that are marked for later removal.
is_draft()
Messages that have not completed composition.
is_flagged()
Messages that are flagged for urgent/special attention.
is_new()
Messages that are recently arrived (this session is the first to have been notified
about these messages) and have not been read.
is_old()
Messages that are not recently arrived (this session is not the first to have been
notified about these messages) and have not been read.
is_recent()
Messages that are recently arrived (this session is the first to have been notified
about these messages).
is_seen()
Messages that have been read.
is_unanswered()
Messages that have not been answered.
is_undeleted()
Messages that are not marked for later removal.
is_undraft()
Messages that have completed composition.
is_unflagged()
Messages that are not flagged for urgent/special attention.
is_unseen()
Messages that have not been read.
The following method can be used to search for messages that have a specific flag set:
has_flag(keyword)
Messages with the specified keyword flag (string) set.
The following methods can be used to search for messages based on their size:
is_larger(size)
Messages that are larger than the size (number) in octets (bytes).
is_smaller(size)
Messages that are smaller than the size (number) in octets (bytes).
The following methods can be used to search for messages based on their age:
is_newer(age)
Messages that are newer than the age (number) in days.
is_older(age)
Messages that are older than the age (number) in days.
The following methods can be used to search for messages based on their arrival or sent
date, in the “day-month-year” form, where day is the day of the month as a decimal number
(01-31), month is the abbreviated month ( “Jan”, “Feb”, “Mar”, “Apr”, “May”, “Jun”, “Jul”,
“Aug”, “Sep”, “Oct”, “Nov”, “Dec”) and year is the year as decimal number including the
century (eg. 2007):
arrived_before(date)
messages that have arrived before the date (string), where date is in the
“day-month-year” form.
arrived_on(date)
Messages that have arrived on the date (string), where date is in the
“day-month-year” form.
arrived_since(date)
Messages that have arrived after the date (string), where date is in the
“day-month-year” form.
sent_before(date)
Messages that have been sent before the date (string), where date is in the
“day-month-year” form.
sent_on(date)
Messages that have been sent on the date (string), where date is in the
“day-month-year” form.
sent_since(date)
Messages that have been sent after the date (string), where date is in the
“day-month-year” form.
The following methods can be used to search for messages that contain a specific word or
phrase:
contain_bcc(string)
Messages that contain the string (string) in the “Bcc” header field.
contain_cc(string)
Messages that contain the string (string) in the “Cc” header field.
contain_from(string)
Messages that contain the string (string) in the “From” header field.
contain_subject(string)
Messages that contain the string (string) in the “Subject” header field.
contain_to(string)
Messages that contain the string (string) in the “To” header field.
contain_field(field, string)
Messages that contain the string (string) in the field (string) header field.
contain_body(string)
Messages that contain the string (string) in the message body.
contain_message(string)
Messages that contain the string (string) in the message.
The following methods can be used to search for messages that match a specific regular
expression pattern.
This way of searching is not supported by the IMAP protocol, and this means that what
actually happens under the hood, is that the relevant parts of all the messages are
downloaded and matched locally. It is therefore recommended to use these methods with meta-
searching (see following section), in order to narrow down the set of messages that should
be searched, and thus minimize what will be downloaded.
Note that due to Lua using backslash ‘\’ as an escape character for its strings, one has to
double backslashes in order to insert a single backslash inside a regular expression
pattern:
match_bcc(pattern)
Messages that match the regular expression pattern (string) in the “Bcc” header
field.
match_cc(pattern)
Messages that match the regular expression pattern (string) in the “Cc” header
field.
match_from(pattern)
Messages that match the regular expression pattern (string) in the “From” header
field.
match_subject(pattern)
Messages that match the regular expression pattern (string) in the “Subject” header
field.
match_to(pattern)
Messages that match the regular expression pattern (string) in the “To” header
field.
match_field(field, pattern)
Messages that match the regular expression pattern (string) in the field (string)
header field.
match_header(pattern)
Messages that match the regular expression pattern (string) in the message header.
match_body(pattern)
Messages that match the regular expression pattern (string) in the message body.
match_message(pattern)
Messages that match the regular expression pattern (string) in the message.
The following method can be used to search for messages using user queries based on the IMAP
specification (RFC 3501 Section 6.4.4):
send_query(criteria)
Searches messages by sending an IMAP search query as described in the search
criteria (string).
Examples:
results = myaccount.mymailbox:select_all()
results = myaccount.mymailbox:is_new()
results = myaccount.mymailbox:is_recent()
results = myaccount.mymailbox:is_larger(100000)
results = myaccount.mymailbox:is_older(10)
results = myaccount.mymailbox:has_flag('MyFlag')
results = myaccount.mymailbox:arrived_before('01-Jan-2007')
results = myaccount.mymailbox:sent_since('01-Jan-2007')
results = myaccount.mymailbox:contain_subject('test')
results = myaccount.mymailbox:contain_field('Sender', 'user@host')
results = myaccount.mymailbox:contain_body('hello world')
results = myaccount.mymailbox:match_from('.*(user1|user2)@host')
results = myaccount.mymailbox:send_query('ALL')
results = myaccount['mymailbox']:is_new()
results = myaccount['myfolder/mymailbox']:is_recent()
RESULTS
After one of more searching methods have been applied to one or more mailboxes, the result
contains all the necessary information, such as which messages matched in which mailboxes.
Using this result these messages can be either searched further or processed in various way.
META-SEARCHING
The results of the searching methods can be searched further on in the same way as searching
is done in mailboxes. The difference is that instead of doing the search in the whole
mailbox, ie. in all the messages, it is instead done only to those messages that were
returned in a previous search.
Examples:
results:match_message('^[Hh]ello world!?$')
myaccount.mymailbox:is_new():match_body('^[Ww]orld, hello!?$')
PROCESSING
The processing methods are applied to the results that searching returned.
The following method can be used to delete messages in a mailbox:
delete_messages()
Deletes the messages that matched.
The following methods can be used to copy and move messages in a mailbox at the same or
different accounts. If the destination mailbox is in a different account than the source
mailbox, then the messages are downloaded and then uploaded to the destination:
copy_messages(destination)
Copies the messages to the destination, which is a mailbox at an account.
move_messages(destination)
Moves the messages to the destination, which is a mailbox at an account.
The following methods can be used to mark messages in a mailbox:
mark_answered()
Marks the messages as answered.
mark_deleted()
Marks the messages for later removal.
mark_draft()
Marks the messages as draft.
mark_flagged()
Marks the messages for urgent/special attention.
mark_seen()
Marks the messages as read.
unmark_answered()
Unmarks the messages that have been marked as answered.
unmark_deleted()
Unmarks the messages that have been marked for later removal.
unmark_draft()
Unmarks the messages that have been marked as draft.
unmark_flagged()
Unmarks the messages that have been marked for urgent/special attention.
unmark_seen()
Unmarks the messages that have been marked as read.
The following methods can be used to flag messages in a mailbox. The standard system flags
are “\Answered”, “\Deleted”, “\Draft”, “\Flagged”, “\Seen”, while if the server supports it,
new user keywords may be defined:
add_flags(flags)
Adds the flags (table that contains strings) to the messages.
remove_flags(flags)
Removes the flags (table that contains strings) from the messages.
replace_flags(flags)
Replaces the flags (table that contains strings) of the messages.
Examples:
results:delete_messages()
results:copy_messages(myaccount.myothermailbox)
results:move_messages(myotheraccount.mymailbox)
results:mark_seen()
results:unmark_flagged()
results:add_flags({ 'MyFlag', '\\Seen' })
results:remove_flags({ '\\Seen' })
results:move_messages(myotheraccount['myfolder/mymailbox'])
MESSAGES
The messages that are residing in any mailbox can be also accessed, as a whole or in parts.
Messages can be accessed using their unique identifier (UID):
myaccount.mymailbox[22]
The UIDs of messages the user is interested in, are gained from the results of searching:
results = account.INBOX:is_unseen()
for _, message in ipairs(results) do
mailbox, uid = table.unpack(message)
header = mailbox[uid]:fetch_header()
end
FETCHING
The following methods can be used to fetch parts of messages. The methods return a string.
The downloaded message parts are cached locally, so they can be reused inside the same
program session:
fetch_message()
Fetches the header and body of the message.
fetch_header()
Fetches the header of the message.
fetch_body()
Fetches the body of the messages.
fetch_field(field)
Fetches the specified header field (string) of the message.
fetch_part(part)
Fetches the specified part (string) of the message.
The following methods can be used to fetch details about the state of a message:
fetch_flags()
Fetches the flags of the message. Returns a table of strings.
fetch_date()
Fetches the internal date of the message. Returns a string.
fetch_size()
Fetches the size of the message. Returns a number.
fetch_structure()
Fetches the body structure of the message. Returns a table that has as keys the
parts of the message, and as values a table that has one mandatory element, the type
(string) of the part, and two optional elements, the size (number) and name (string)
of the part.
APPENDING
The following methods can be used to append a message to a mailbox:
append_message(message)
Appends the message (string) to the mailbox.
append_message(message, flags, date)
Appends the message (string) to the mailbox, setting the specified flags (table of
strings), as returned by fetch_flags(), and date (string), as returned by
fetch_date().
Examples:
myaccount.mymailbox[2]:fetch_message()
myaccount.mymailbox[3]:fetch_field('subject')
myaccount.mymailbox[5]:fetch_part('1.1')
myaccount['mymailbox'][7]:fetch_message()
myaccount['myfolder/mymailbox'][11]:fetch_message()
myaccount.mymailbox:append_message(message)
FUNCTIONS
The following auxiliary functions are also available for convenience:
form_date(days)
Forms a date in “day-month-year” format that the system had before the number of
days (number), and returns it as a string.
get_password(prompt)
Displays the specified prompt (string), and reads a password, while character
echoing is turned off. Returns that password as a string.
become_daemon(interval, commands)
Detaches the program from the controlling terminal and runs it in the background as
system daemon. The program will then repeatedly poll at the specified interval
(number) in seconds. Each time the program wakes up, the commands (function) are
executed.
become_daemon(interval, commands, nochdir, noclose)
Detaches the program from the controlling terminal and runs it in the background as
system daemon. The program will then repeatedly poll at the specified interval
(number) in seconds. Each time the program wakes up, the commands (function) are
executed.
If nochdir (boolean) is “true”, the current working directory is not changed to the
root directory (/). If noclose (boolean) is “true”, the standard input, standard
output and standard error are not redirected to /dev/null.
pipe_to(command, data)
Executes the system's command (string) and sends the data (string) to the standard
input channel of the subprocess. Returns a number, the exit status of the child
process.
pipe_from(command)
Executes the system's command (string) and retrieves the data from the standard
output channel of the subprocess. Returns a number, the exit status of the child
process, and a string, the output of the child process.
regex_search(pattern, string)
Implements Perl-compatible regular expressions (PCRE). The pattern (string) is a
PCRE pattern. The string (string) is the subject string in which the pattern is
matched against. Returns at least a boolean, that denotes if the match was
successful, and any captures which are of string type. Note that due to Lua using
backslash ‘\’ as an escape character for its strings, one has to double backslashes
in order to insert a single backslash inside a regular expression pattern:
Examples:
date = form_date(14)
password = get_password('Enter password: ')
become_daemon(600, myfunction)
status = pipe_to('mycommandline', 'mydata')
status, data = pipe_from('mycommandline')
success, capture = regex_search('^[PpCcRrEe]: (\\w)$', 'mystring')
EXAMPLES
See samples/config.lua and samples/extend.lua in the source code distribution.
ENVIRONMENT
HOME User's home directory.
SEE ALSO
imapfilter(1)