[Chandler-dev] "Precondition failed" for subscription to ICS calendar

Thu Dec 13 12:39:52 PST 2007

On Dec 11, 2007, at 8:58 AM, Morgen Sagen wrote:

> That 412 status is probably coming from your HTTP server.  Can you  
> check your Apache logs to see what the request/response looks like?

The Apache access log contains repeated patterns that look like this:

192.168.0.10 - - [13/Dec/2007:11:29:06 -0800] "GET /~greg/shared/ 
Greg.ics HTTP/1.1" 200 110986
192.168.0.10 - - [13/Dec/2007:11:30:03 -0800] "PUT /~greg/shared/ 
Greg.ics HTTP/1.1" 412 332

That is, it does a successful GET followed about a minute later by an  
unsuccessful PUT.  Since this subscription should be read-only, why  
is Chandler trying to PUT something?

The Chandler log is full of things that look like this:

2007-12-10 13:08:32,173 twisted WARNING: [End 412 Response]:
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 
<<<<<<<<
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<HTML><HEAD>
<TITLE>412 Precondition Failed</TITLE>
</HEAD><BODY>
<H1>Precondition Failed</H1>
The precondition on the request for the URL /~greg/shared/Greg.ics  
evaluated to false.<P>
<HR>
<ADDRESS>Apache/1.3.33 Server at gregor.local Port 80</ADDRESS>
</BODY></HTML>

 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
 >>>>>>>>>

2007-12-10 13:08:32,208 osaf.sharing ERROR: Error syncing collection
Traceback (most recent call last):
   File "/Applications/Chandler_ppc-osx_0.7.3.app/Contents/Resources/ 
parcels/osaf/sharing/__init__.py", line 371, in run
     activity=activity, forceUpdate=forceUpdate))
   File "/Applications/Chandler_ppc-osx_0.7.3.app/Contents/Resources/ 
parcels/osaf/sharing/shares.py", line 773, in sync
     debug=debug)
   File "/Applications/Chandler_ppc-osx_0.7.3.app/Contents/Resources/ 
parcels/osaf/sharing/webdav_conduit.py", line 423, in sync
     debug=debug)
   File "/Applications/Chandler_ppc-osx_0.7.3.app/Contents/Resources/ 
parcels/osaf/sharing/recordset_conduit.py", line 84, in sync
     debug=debug)
   File "/Applications/Chandler_ppc-osx_0.7.3.app/Contents/Resources/ 
parcels/osaf/sharing/recordset_conduit.py", line 990, in _sync
     self.putRecords(toSend, extra, debug=debug, activity=activity)
   File "/Applications/Chandler_ppc-osx_0.7.3.app/Contents/Resources/ 
parcels/osaf/sharing/recordset_conduit.py", line 1249, in putRecords
     self.put(text)
   File "/Applications/Chandler_ppc-osx_0.7.3.app/Contents/Resources/ 
parcels/osaf/sharing/webdav_conduit.py", line 490, in put
     details="Received [%s]" % resp.body)
SharingError: Precondition Failed (HTTP status 412)

-- Greg Noel, retired UNIX guru