WebDAV - Handling special characters and name duplicates

1 Initial Problem

ILIAS supports functionalities in its repository, which are not supported by some file systems and are therefore not allowed by WebDAV. The WebDAV protocol only allows to answer requests with primitive http status codes like “403 Forbidden” and “405 Method Not Allowed”. Some WebDAV clients even encapsulates a “403 Forbidden” response with a “Not able to read data source” or something like that (Windows Explorer). It is not possible to give a response in form of a text.

This feature request tackles following two cases in which no good response can be given to a WebDAV-client:

• NTFS (Windows) does not allow the characters \/:*?”<>| in a file name. Because of that, the WebDAV Service on ILIAS is implemented to not list files and folders with one of these characters. As mentioned, the user cannot be informed about that over WebDAV.
• Theoretically, WebDAV clients (even Windows Explorer) can display name duplicates. But they are not supported by most (if not all) file systems and cause problems if an entire folder is copied to the computer. Since the WebDAV objects are identified by their URI and therefore by the displayed name (which is the object title), it is impossible to differentiate between two objects with the same title.

2 Conceptual Summary

This feature request suggests a WebDAV-information file, which is shown over WebDAV if a problem occurs that cannot be communicated in the http response headers. The File contains an error title, prefaced by a #-Symbol, a short description of the error (why it happened) and a list of affected files and folders. The file is named “!_WEBDAV_INFORMATION.txt”. With the ‘!’, it will show up on top of all files and the title is capitalized to get the users attention.

With this feature request, we also would like to remove the information text in ILIAS, which is presented to the user if a file or folder cannot be displayed over WebDAV.

3 User Interface Modifications

3.1 List of Affected Views

{Please list all views (screens) of ILIAS that should be modified, newly introduced or removed.}

3.2 User Interface Details

If the user requests a folder over WebDAV that contains a file or folder with one of these two problems, it will show the information file. It would look like this:

The file has a “.txt” extension, so it can be opened with a simple text editor. The content looks like this:

4 Technical Information

The shown information file is just virtual and will therefore be generated and sent to the client without creating anything on ILIAS.

5 Contact

• Author of the Request: Heer, Raphael [rheer]
• Maintainer: Kergomard, Stephan [skergomard], Heer, Raphael [rheer]
• Implementation of the feature is done by: Heer, Raphael [rheer]

6 Funding

If you are interest in funding this feature, please add your name and institution to this list.

• …

7 Discussion

Kunkel, Matthias [mkunkel], 25 APR 2019 : Great to get rid of the "Due to one of the following..." message in the ListGUI. It made me always crazy…

JourFixe, ILIAS [jourfixe], 07 MAY 2019 : We highly appreciate this suggestion and schedule the feature for 6.0.

8 Implementation

The implementation is not visible in the web interface. The view in Windows Explorer is still identical to the print screens in section 3.2 above.

Test Cases

Test cases completed at {date} by Kergomard, Stephan [skergomard]

• #31969 : Open course containing multiple folders and files with the same title
• #31970 : Open Course Containing Objects with Forbidden Characters in Title

Approval

Approved at 6.12.19 by Kergomard, Stephan [skergomard]{user}.