XML response has incorrect Content-Type on some errors

[Matt Muller]

curl -v -H "Content-Type: text/xml" --data @body.xml http://$USER:$PASS@trac/login/xmlrpc

POST /login/xmlrpc HTTP/1.1
Authorization: Basic 
User-Agent: curl/7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 
Host: trac
Accept: */*
Content-Type: text/xml
Content-Length: 273

The XMLRPC plugin is supposed to detect the Content-Type and send back a response with the same Content-Type:

HTTP/1.1 200 OK
Date: Thu, 12 Sep 2013 18:23:23 GMT
Server: Apache/2.2.22
Content-Length: 2509
Vary: Accept-Encoding
Content-Type: text/xml

However, if I send an XMLRPC request that attempts to perform an invalid action on a ticket (for example, the workflow does not allow a ticket with the status 'new' to be set as 'in_QA'), the plugin sends back a different Content-Type (though still with a 200 OK header):

HTTP/1.1 200 OK
Date: Thu, 12 Sep 2013 18:24:20 GMT
Server: Apache/2.2.22
Content-Length: 345
Content-Type: application/xml

While this might not be a problem for some client libraries, the Ruby XMLRPC::Client library requires a text/xml content type.

Suspected Cause/Solution:

On line 130 of tracrpc/xml_rpc.py, this is how the plugin sends a (correct) response for some specified error codes:

130 self._send_response(req, xmlrpclib.dumps(fault), rpcreq['mimetype'])

On line 140, where the (incorrect) response is sent for all other types of errors, the plugin leaves out the rpcreq['mimetype'] argument:

140 self._send_response(req,
141      xmlrpclib.dumps(
142            xmlrpclib.Fault(err_code,
143                 "'%s' while executing '%s()'" % (str(e), method))))

I believe changing this to the following will fix the problem:

140 self._send_response(req,
141       xmlrpclib.dumps(
142              xmlrpclib.Fault(err_code,
143                     "'%s' while executing '%s()'" % (str(e), method))), rpcreq['mimetype'])

[Olemis Lang]

This is an interesting issue I'll write a test case to reproduce this situation . I'm sure osimons will add comments on this subject soon .

Thanks for reporting this issue.

[Ben Allen]

I can verify that manually applying this patch to the current codebase (r13203) resolved my problems running XMLRPC calls from Ruby scripts. That particular call to the _send_response function is the only one in that file that doesn't pass rpcreq['mimetype'] as the third argument.

[osimons]

In 13637:

XmlRpcPlugin: Fixed missing mimetype when returning error for unknown faults. Closes #11321.

Thanks to mattinflection for report + patch, and to AllenB for verification.