druido [druido]

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I have written a module for Drupal 6.x (not tested on Drupal 7 yet), called File Taxonomy Server Lite (fts_lite for short), which provides access to Drupal files using taxonomies through WebDAV. The idea for the module comes from File Server (http://drupal.org/project/fileserver), but the code has been completely re-written and the functionality is somewhat improved.

The module only depends on the DAV module (http://drupal.org/project/dav) and Drupal's Core Upload. It does *not* depend in any way on File Framework (as File Server and File Relations do) – that's why it is "lite". To my knowledge, this would be the only published module to implement WebDAV access to files that works with the core.

For the module to work, nodes with associated file attachments must be tagged by terms of some vocabularies. Then, by exposing such vocabularies through WebDAV, the user gains access to such files.

The module promotes (some would say "enforce") the policy "one node - one file". To use the module, the user must designate a content type for files and upload a single file to each node of that type (in the current implementation, if a node contains multiple attachments, only the first will be visible through WebDAV).

The module works as follows: the user chooses one or more vocabularies to be exposed through WebDAV. After that, the user can login using her/his WebDAV client and will be presented a "file system" view of the selected vocabularies. Vocabularies are mapped onto top directories, while terms are subdirectories containing other term-directories and files (which are the files associated to nodes tagged by the given term).

The user has the ability to upload/move/copy/delete/download files and folders. The semantics of such operations, although intuitive, is not exactly the same as for a real file system, but it closely reflects the behaviour of Drupal's interface for manipulating taxonomies. Some examples:

1) moving a file to a different subdirectory just re-tags the associated node;
2) copying a file to a different subdirectory adds a term to the associated node;
4) moving a subdirectory corresponds to moving a term (moving to different vocabularies and promoting a term to a vocabulary are also allowed);
etc…

Deletion of files corresponds to untagging files and deletion of folders corresponds to deletion of terms and/or vocabularies. Nodes and attached files *cannot* be deleted through WebDAV (although, in the future, an option to allow that may be implemented). In this sense, the module is safe, because it is not possible to inadvertently delete a node or a file. The module also supports node revisions (if enabled for the designated content type).

The module already supports any kind of vocabulary, including free tagging vocabularies and multiple choice vocabularies.

One of the design goals of my project is information integrity (efficiency has a lower priority): no data should be inadvertently lost by operations through WebDAV. I have already mentioned that nodes/files cannot be deleted. Also, term synonyms and relations are preserved (if possible). Note that some operations are far from being trivial: consider, for example, moving a term containing a bunch of sub-terms with multiple parents and relations to a different vocabulary. Some information loss in this case may be inevitable (some parents and some relations may be lost), because the "file system" view is a tree whereas the taxonomy is a dag, but great care has been taken to minimize such loss (a user preference to forbid moving terms across vocabularies is planned, however).

To achieve the best consistency with the web interface, all operations make use of drupal_execute() rather than "lower level" methods (e.g., directly calling node_save() or directly accessing the database), to ensure that all validations are performed.

Another design goal is security: only users who have been granted permissions to access the files are able to so.

To summarize, the module has *complete* functionality to manage files through WebDAV in a safe way and it is the only module that does that. By depending only on Core Upload, I believe that it may have more widespread use than File Server or File Relations, which require the complex File Framework. If complemented with tac_lite (for example), it may easily provide "automatic" access control for files (e.g., upload a file to have it automagically accessible only by a given role or user). Its main limitations are the limitations of the DAV module (e.g., some clients do not display filenames but id's, …)

Features that may be added in the future include:

0) more user preferences (e.g., choose the semantics for file deletion);
1) support for CCK File Upload;
2) support for multiple attachments to each node;
3) support for WebDAV module (already partially implemented), as an alternative.
4) support for OG vocabularies.

My contact email is

nvitacolonna@gmail.com

Sincerely,
druido