Added a flag (_send_traceback_header) to the SimpleXMLRPCServer class

that allows sending back exception/stack trace information about
internal server errors (this flag defaults to False to avoid sending
such information unless explicitly enabled).  Added tests to verify
behavior of this new feature (these tests are skipped on win32 because
of problems with WSAEWOULDBLOCK). Renamed HTTPTestCase to
SimpleServerTestCase. [GSoC - Alan McIntyre]

Lib/SimpleXMLRPCServer.py

@@ -105,6 +105,7 @@ import SocketServer
 import BaseHTTPServer
 import sys
 import os
+import traceback
 try:
     import fcntl
 except ImportError:
@@ -470,9 +471,16 @@ class SimpleXMLRPCRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
             response = self.server._marshaled_dispatch(
                     data, getattr(self, '_dispatch', None)
                 )
-        except: # This should only happen if the module is buggy
+        except Exception, e: # This should only happen if the module is buggy
             # internal error, report as HTTP server error
             self.send_response(500)
+
+            # Send information about the exception if requested
+            if hasattr(self.server, '_send_traceback_header') and \
+                    self.server._send_traceback_header:
+                self.send_header("X-exception", str(e))
+                self.send_header("X-traceback", traceback.format_exc())
+
             self.end_headers()
         else:
             # got a valid XML RPC response
@@ -517,6 +525,12 @@ class SimpleXMLRPCServer(SocketServer.TCPServer,
 
     allow_reuse_address = True
 
+    # Warning: this is for debugging purposes only! Never set this to True in
+    # production code, as will be sending out sensitive information (exception
+    # and stack trace details) when exceptions are raised inside
+    # SimpleXMLRPCRequestHandler.do_POST
+    _send_traceback_header = False
+
     def __init__(self, addr, requestHandler=SimpleXMLRPCRequestHandler,
                  logRequests=True, allow_none=False, encoding=None, bind_and_activate=True):
         self.logRequests = logRequests