When using WebDav, open file fails with error msg 'Premature end of file.'

#1

Hello,

When using WebDav web server (IIS 8) with GanttProject, opening file gives error message ‘Premature end of file.’. Saving file to WebDav folder works ok. I have checked that .gan file which I try to open is not empty and looks ok. If I copy it to my local hard disk, it opens without error messages.

Any idea what could be wrong? GanttProject is version 2.8.8.

Rgds, Asko

#2

Please post the contents of the log after file opening. Help > View log

#3

Hello,

Here is attached log file from WebDav file open process:
GanttProjet_WebDav_File-open.zip (2.3 KB)

For the reference, here is attached log file from WebDav file save process, which works ok:
GanttProjet_WebDav_File-save.zip (1.4 KB)

Best regards, Asko

#4

I see authentication warnings, which may or may not be the issue. It probably depends on how your WebDAV server behaves in case of authentication errors. You may try downloading a build of GP 2.8.9 where we updated WebDAV library and enabled some additional logging.

Here is a Dropbox folder with packages: https://www.dropbox.com/sh/0gwuayq6vg0kyss/AAApogLPlvpg0lY9JltS-3sZa?dl=0

You need to open file logging.properties which sits at the top level of GP install folder and replace

io.milton.httpclient.level = INFO

with

io.milton.httpclient.level = FINEST
#5

Tried with ver. 2.8.9 and result is the same (error msg premature end of file).

Attached log with log setting io.milton.httpclient.level = FINEST:
GanttProjet-2.8.9_WebDav_File-open.zip (2.7 KB)

BR Asko

#6

So it looks like your server really returns empty file.

#7

Any idea, what causes this behavior?

If I open WebDav folder with Windows File Explorer, copy file to local disk and then open local copy with GanttProject, it opens without errors and displays correct data.

Also, I can save .gan file with Ganttproject to WebDav folder without errors and saved file is what it should be.

BR Asko

#8

You may want to examine your server logs to investigate the reasons. I don’t know how Windows Explorer communicates with WebDAV folder and not sure if it does so at all (Windows client and server may easily use other communication protocols)

#9

I disabled windows authentication (basic authentication is enabled) from IIS WebDav and tested WebDav folder read&write with WinSCP client, both read&write works.

Tested again with same IIS WebDav settings with GanttProject, resulting same error ‘premature end of file’. Log file:
GanttProjet-2.8.9_WebDav_File-open.zip (2.5 KB)

As WinSCP works with WebDav server using basic authentication, I don’t think that there is anything wrong in the WebDav server & folder settings.

#10

You will get the most precise answer from the server logs. WebDAV is a complex protocol, and can be misinterpreted by both server and client. If you want to troubleshoot particular GanttProject client, you need to know what exactly is returned to its requests.