WebDAV¶

Module: mod_webdav

• Table of contents
• WebDAV
  • Description
  • Options
  • Examples
  • symlinks
  • litmus tests
  • Limitations
  • Installation
    • PUT, DELETE, COPY, MOVE, MKCOL
    • PROPFIND, PROPPATCH
    • LOCK, UNLOCK

Description¶

The WebDAV module is an implementation of RFC 4918. (since 1.4.54)

Supported methods:

• PROPFIND
• PROPPATCH
• OPTIONS
• MKCOL
• COPY
• MOVE
• DELETE
• PUT
• LOCK
• UNLOCK

and the usual GET, POST, HEAD from HTTP/1.1.

Mounting an open-access WebDAV resource into Windows 10, Windows XP (Network Places), Mac OS X (Finder) and Linux (Konqueror) works. Mounting an authenticated WebDAV resource works in Mac OS X and Linux. litmus tests pass since lighttpd 1.4.54.

Options¶

• webdav.activate
  If you load the webdav module, the WebDAV functionality has to be enabled for the directories you want to provide to the user.
  Default: disable

• webdav.is-readonly
  Only allow reading methods (GET, PROPFIND, OPTIONS) on WebDAV resources.
  Default: disable (i.e. writable)

• webdav.sqlite-db-name
  The full path to the file you would like to use as your db file. This is required for webdav props and locks.
  Default: (empty)

• webdav.opts (since 1.4.54)
  List of additional options to configure mod_webdav.
  Default: (empty)
  webdav.opts = ("propfind-depth-infinity" => "enable") (default: "disable") (since 1.4.56)
  Permit PROPFIND with request header "Depth: infinity"
  webdav.opts = ("deprecated-unsafe-partial-put" => "enable") (default: "disable") (since 1.4.54)
  Versions of mod_webdav earlier than 1.4.54 were not RFC compliant and permitted partial PUT, which is unsafe. In lighttpd 1.4.54, this is disabled by default, and the unsafe behavior can be enabled with the following option, provided for backwards compatibilty.
  webdav.opts = ("unsafe-propfind-follow-symlink" => "enable") (default: "disable") (since 1.4.56)
  Instruct PROPFIND to follow symlinks if and only if webdav.is-readonly = "enable" is also set. WebDAV does not have a concept of symlinks. See symlinks

Examples¶

To enable WebDAV for the /dav directory, you wrap your webdav options in a conditional. You have to use the regex like below as you want to match the directory /dav and everything below it, but not e.g. /davos.

  $HTTP["url"] =~ "^/dav($|/)" {
    webdav.activate = "enable" 
    webdav.is-readonly = "enable" 
    webdav.sqlite-db-name = "/var/db/lighttpd/webdav.db" 
  }

If you would like LOCK support:

  $HTTP["url"] =~ "^/dav($|/)" {
    webdav.activate = "enable" 
    #webdav.is-readonly = "disable" # (default)
    webdav.sqlite-db-name = "/var/db/lighttpd/webdav.db" 
  }

symlinks¶

WebDAV resource and collection concepts do not perfectly map one-to-one with the unix filesystem semantics. For example, WebDAV does not have the concept of symlinks. lighttpd mod_webdav delegates GET, HEAD, POST handling to other lighttpd modules, which generally do handle symlinks. However, WebDAV methods like PROPFIND may reject symlinks to a directory unless both webdav.opts = ("unsafe-propfind-follow-symlink" => "enable") and webdav.is-readonly = "enable" are set and the resulting behavior and restrictions are acceptable.

When symlinks are used to map different paths into a single tree for the web server, an alternative with mod_webdav is to use mod_alias instead of symlinks, and to have a separate webdav.sqlite-db-name database for each of the directory targets; multiple WebDAV roots instead of a single top-level WebDAV root.

Another option on some OS, bind mounts (mount --bind) might be used to map one filesystem location under another tree.

litmus tests¶

We use http://webdav.org/neon/litmus/ (version 0.13) to verify that we support the WebDAV spec. (#1818)

Aside: the only litmus test which does not pass has to do with XML validation, which libxml2 warns about but does not report as an error.

Sample litmus.conf to run litmus tests in /dev/shm (temporary; not persistent):

#mkdir -p /dev/shm/dav /dev/shm/db
#cp /usr/share/litmus/htdocs/foo /dev/shm/dav/
#lighttpd -D -f litmus.conf &
#cd /dev/shm  # litmus writes child.log and debug.log to current dir
#/usr/bin/litmus -k http://127.0.0.1:8080/ -d /dev/shm/dav
#kill %1      # kill lighttpd process started above
#rm -rf /dev/shm/{dav,db,child.log,debug.log}

server.document-root = "/dev/shm/dav" 
server.bind = "127.0.0.1" 
server.port = 8080
mimetype.assign += ( "" => "application/octet-stream" )

server.modules += ( "mod_webdav" )
webdav.activate = "enable" 
webdav.sqlite-db-name = "/dev/shm/db/webdav.db" 

Limitations¶

(incomplete list)

• incomplete "shared" lock support

Installation¶

PUT, DELETE, COPY, MOVE, MKCOL¶

mod_webdav is part of the 1.4.x distribution and supports GET, HEAD, OPTIONS, PUT, DELETE, COPY, MOVE, MKCOL without any additional libraries.

PROPFIND, PROPPATCH¶

PROPFIND and PROPPATCH are used to do a directory-listing and to attach properties to a file-object. This involves parsing XML-data and storing the properties. To compile mod_webdav with property-support libxml2, libxml2-devel, sqlite, sqlite-devel packages are required and you have to build with:

$ configure --with-webdav-props

LOCK, UNLOCK¶

LOCK and UNLOCK are necessary to get mounting of file-systems working. This involves generate unique lock-tokens. We use libuuid for this job from packages e2fsprogs, e2fsprogs-devel. LOCK with includes parsing XML again, so have to provide the dependencies of the previous section and libuuid:

$ ./configure --with-webdav-props --with-webdav-locks