simonchen / webdavfs

Linux / OSX FUSE webdav filesystem. This filesystem behaves like a real network filesystem- no unnecessary copying of entire files.

webdavfs

This is forked from miquels/webdavfs I've maded some improvements to add new options and better performance.

A FUSE filesystem for WEBDAV shares.

Most filesystem drivers for Webdav shares act somewhat like a mirror; if a file is read it's first downloaded then cached in its entirety on a local drive, then read from there. Writing files is similar or even worse- a partial update to a file might involve downloading it first, modifying it, then uploading it again. In many cases that is not optimal.

This filesystem driver behaves like a network filesystem. It doesn't cache anything locally, it just sends out partial reads/writes over the network.

For that to work, you need partial write support- and unfortunately, there is no standard for that. See https://blog.sphere.chronosempire.org.uk/2012/11/21/webdav-and-the-http-patch-nightmare

However, there is support in Apache (the webserver, using mod_dav) and SabreDav (a php webserver server library, used by e.g. NextCloud) for partial writes. So we detect if it's Apache or SabreDav we're talking to and then use their specific methods to partially update files.

If no support for partial writes is detected, mount.webdavfs will print a warning and mount the filesystem read-only. In that case you can also use the rwdirops mount option, this will make metadata writable (i.e. you can use rm / mv / mkdir / rmdir) but you still won't be able to write to files.

But if you only need to read files it's still way faster than davfs2 :)

Cross-compile

Avoiding to call gcc compiler

go env -w CGO_ENABLED=0

What is working

Basic filesystem operations.

• files: create/delete/read/write/truncate/seek
• directories: mkdir rmdir readdir
• query filesystem size (df / vfsstat)

What is not yet working

• locking

What will not ever work

• change permissions (all files are 644, all dirs are 755)
• change user/group
• devices / fifos / chardev / blockdev etc
• truncate(2) / ftruncate(2) for lengths between 1 .. currentfilesize - 1

This is basically because these are mostly just missing properties from webdav.

How to install and use.

First you need to install golang, git, fuse, and set up your environment.

Note that you need at least Go 1.4 (probably 1.6). If you're on Debian, everything before Debian 8 (jessie) is too old. On jessie you need to add the jessie-backports source, then install go from backports.

# echo "deb http://ftp.debian.org/debian jessie-backports main" > /etc/apt/sources.list.d/jessie-backports.list
# apt-get update
# apt-get install -t jessie-backports golang

Then if your Go version is up to date, continue:

$ su -m
Password:
# apt-get install golang
# apt-get install git
# apt-get install fuse
# exit
$ cd
$ mkdir pkg bin src
$ export GOPATH=$HOME

Now with go and git installed, get a copy of this github repository:

$ cd src
$ mkdir -p github.com/miquels
$ cd github.com/miquels
$ git clone https://github.com/miquels/webdavfs
$ cd webdavfs

You're now ready to build the binary:

$ go get
$ go build

And install it:

$ su -m
Password:
# cp webdavfs /sbin/mount.webdavfs

Using it is simple as:

# mount -t webdavfs -ousername=you,password=pass https://webdav.where.ever/subdir /mnt

Command line options

Option	Description
-f	don't actually mount
-D	daemonize
-T opts	trace options: fuse,webdav,httpreq,httphdr
-F file	trace file. file will be reopened when renamed, tracing will stop when file is removed
-o opts	mount options

Mount options

Option	Description
allow_root	If mounted as normal user, allow access by root
allow_other	Allow access by others than the mount owner. This
	also sets "default_permisions"
default_permissions	As per fuse documentation
no_default_permissions	Don't set "default_permissions" with "allow_other"
ro	Read only
rwdirops	Read-write for directory operations, but no file-writing (no PUT)
rw	Read-write (default)
uid	User ID for filesystem
gid	Group ID for filesystem.
mode	Mode for files/directories on the filesystem (600, 666, etc).
	Files will never have the executable bit on, directories always.
cookie	Authorization Cookie (Useful for O365 Sharepoint/OneDrive for Business)
password	Password of webdav user
username	Username of webdav user
async_read	As per fuse documentation
nonempty	As per fuse documentation
maxconns	Maximum number of parallel connections to the webdav
	server (default 8)
maxidleconns	Maximum number of idle connections (default 8)
** NEW Options [2022-12-3] **
readbuff	1024 (default) How many bytes fetched from webdav server
usepagecache	false (default) use kernel cache for the open file

If the webdavfs program is called via mount -t webdavfs or as mount.webdav, it will fork, re-exec and run in the background. In that case it will remove the username and password options from the command line, and communicate them via the environment instead.

The environment options for username and password are WEBDAV_USERNAME and WEBDAV_PASSWORD, respectively.

In the future it will also be possible to read the credentials from a configuration file.

TODO

• maxconns doesn't work yet. this is complicated with the Go HTTP client.
• add configuration file
• timeout handling and interrupt handling
• we use busy-loop locking, yuck. use semaphores built on channels.
• rewrite fuse.go code to use the bazil/fuse abstraction instead of bazil/fuse/fs.
  perhaps switch to
  • https://github.com/hanwen/go-fuse
  • https://github.com/jacobsa/fuse

Unix filesystem extensions for webdav.

Not ever going to happen, but if you wanted a more unix-like experience and better performance, here are a few ideas:

• Content-Type: for unix pipes / chardevs / etc
• contentsize property (read-write)
• inodenumber property
• unix properties like uid/gid/mode
• DELETE Depth 0 for collections (no delete if non-empty)
• return updated PROPSTAT information after operations like PUT / DELETE / MKCOL / MOVE