NAME

       nbdkit-curl-plugin - nbdkit curl plugin (HTTP, FTP and other protocols)

SYNOPSIS

        nbdkit -r curl [url=]http://example.com/disk.img

DESCRIPTION

       "nbdkit-curl-plugin" is a plugin for nbdkit(1) which turns content served over HTTP, FTP, and more, into
       a Network Block Device.  It uses a library called libcurl (also known as cURL) to read data from URLs.
       The exact list of protocols that libcurl can handle depends on how it was compiled, but most versions
       will handle HTTP, HTTPS, FTP, FTPS and more (see: "curl -V").

       Note: This plugin supports writes.  However for HTTP, you may not want nbdkit to issue PUT requests to
       the remote server (which probably doesn't understand them).  To force nbdkit to use a readonly
       connection, pass the -r flag.

       Although this plugin can access SFTP (ie. SSH) servers, it is much better to use nbdkit-ssh-plugin(1).

EXAMPLE

        nbdkit -r curl http://example.com/disk.img

       serves the remote disk image as NBD on TCP port 10809 (to control ports and protocols used to serve NBD
       see nbdkit(1)).

PARAMETERS

       cookie=COOKIE
       cookie=+FILENAME
           Set a cookie in the request header when connecting to the remote server.

           A typical example is:

            cookie='vmware_soap_session="52a01262-bf93-ccce-d379-8dabb3e55560"'

           This option can be used at most once.  It only works for HTTP and HTTPS transports.  To set multiple
           cookies you must concatenate them yourself, eg:

            cookie='name1=content1; name2=content2;'

           See CURLOPT_COOKIE(3) for more information about this.

           If the cookie is used for authentication then passing it on the command line is not secure on shared
           machines.  Use the alternate "+FILENAME" syntax to pass it in a file.

       password=PASSWORD
           Set the password to use when connecting to the remote server.

           Note that passing this on the command line is not secure on shared machines.

       password=-
           Ask for the password (interactively) when nbdkit starts up.

       password=+FILENAME
           Read the password from the named file.  This is a secure method to supply a password, as long as you
           set the permissions on the file appropriately.

       password=-FD
           Read the password from file descriptor number "FD", inherited from the parent process when nbdkit
           starts up.  This is also a secure method to supply a password.

       protocols=PROTO,PROTO,...
           Limit the protocols that are allowed in the URL.  Use this option for extra security if the URL comes
           from an untrusted source and you want to avoid security isues in the more obscure protocols that curl
           supports.  (See qemu CVE-2013-0249 for an example of a security bug introduced by allowing
           unrestricted protocols).

           For example if you only intend HTTP and HTTPS URLs to be used, then add this parameter:
           "protocols=http,https"

           The value of this parameter is a comma-separated list of protocols.  The following protocols are
           known: dict, file, ftp, ftps, gopher, http, https, imap, imaps, ldap, ldaps, pop3, pop3s, rtmp,
           rtmpe, rtmps, rtmpt, rtmpte, rtmpts, rtsp, scp, sftp, smb, smbs, smtp, smtps, telnet, tftp.

           The default is to allow any protocol.

       proxy-password=PASSWORD
       proxy-password=-
       proxy-password=+FILENAME
       proxy-password=-FD
       proxy-user=USERNAME
           Set the proxy username and password.

       sslverify=false
           Don't verify the SSL certificate of the remote host.

       timeout=SECS
           Set the timeout for requests.

       timeout=0
           Use the default libcurl timeout for requests.

       unix-socket-path=PATH
           Instead of using a TCP connection, connect to the server over the named Unix domain socket.  See
           "CURLOPT_UNIX_SOCKET_PATH" in curl_easy_setopt(3).

       [url=]URL
           The URL of the remote disk image.  This is passed to libcurl directly via "CURLOPT_URL" in
           curl_easy_setopt(3).

           This parameter is required.

           "url=" is a magic config key and may be omitted in most cases.  See "Magic parameters" in nbdkit(1).

       user=USERNAME
           Set the username to use when connecting to the remote server.  This may also be set in the URL (eg.
           "http://foo@example.com/disk.img")

DEBUG FLAG

       -D curl.verbose=1
           This enables very verbose curl debugging.  See CURLOPT_VERBOSE(3).  This is mainly useful if you
           suspect there is a bug inside libcurl itself.

FILES

       $plugindir/nbdkit-curl-plugin.so
           The plugin.

           Use "nbdkit --dump-config" to find the location of $plugindir.

VERSION

       "nbdkit-curl-plugin" first appeared in nbdkit 1.2.

SEE ALSO

       curl(1), libcurl(3), CURLOPT_COOKIE(3) CURLOPT_VERBOSE(3), nbdkit(1), nbdkit-readahead-filter(1),
       nbdkit-retry-filter(1), nbdkit-ssh-plugin(1), nbdkit-plugin(3), http://curl.haxx.se.

AUTHORS

       Richard W.M. Jones

       Parts derived from Alexander Graf's "QEMU Block driver for CURL images".

COPYRIGHT

       Copyright (C) 2014 Red Hat Inc.

LICENSE

       Redistribution and use in source and binary forms, with or without modification, are permitted provided
       that the following conditions are met:

       •   Redistributions of source code must retain the above copyright notice, this list of conditions and
           the following disclaimer.

       •   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
           the following disclaimer in the documentation and/or other materials provided with the distribution.

       •   Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote
           products derived from this software without specific prior written permission.

       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
       INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
       INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
       ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
       DAMAGE.