Ticket #253: render-deferred.patch

server.py

@@ -160 +160 @@
         except:
             self.processingFailed(failure.Failure())
 
-
-    def render(self, resrc):
-        try:
-            body = resrc.render(self)
-        except UnsupportedMethod, e:
-            allowedMethods = e.allowedMethods
-            if (self.method == "HEAD") and ("GET" in allowedMethods):
-                # We must support HEAD (RFC 2616, 5.1.1).  If the
-                # resource doesn't, fake it by giving the resource
-                # a 'GET' request and then return only the headers,
-                # not the body.
-                log.msg("Using GET to fake a HEAD request for %s" %
-                        (resrc,))
-                self.method = "GET"
-                body = resrc.render(self)
-
-                if body is NOT_DONE_YET:
-                    log.msg("Tried to fake a HEAD request for %s, but "
-                            "it got away from me." % resrc)
-                    # Oh well, I guess we won't include the content length.
-                else:
-                    self.setHeader('content-length', str(len(body)))
-
-                self.write('')
-                self.finish()
-                return
-
-            if self.method in (supportedMethods):
-                # We MUST include an Allow header
-                # (RFC 2616, 10.4.6 and 14.7)
-                self.setHeader('Allow', allowedMethods)
-                s = ('''Your browser approached me (at %(URI)s) with'''
-                     ''' the method "%(method)s".  I only allow'''
-                     ''' the method%(plural)s %(allowed) here.''' % {
-                    'URI': self.uri,
-                    'method': self.method,
-                    'plural': ((len(allowedMethods) > 1) and 's') or '',
-                    'allowed': string.join(allowedMethods, ', ')
-                    })
-                epage = error.ErrorPage(http.NOT_ALLOWED,
-                                        "Method Not Allowed", s)
-                body = epage.render(self)
-            else:
-                epage = error.ErrorPage(http.NOT_IMPLEMENTED, "Huh?",
-                                        """I don't know how to treat a"""
-                                        """ %s request."""
-                                        % (self.method))
-                body = epage.render(self)
-        # end except UnsupportedMethod
-
+    def _cbRender(self, body, resrc):
+
         if body == NOT_DONE_YET:
             return
         if type(body) is not types.StringType:
@@ -232 +184 @@
             self.setHeader('content-length', str(len(body)))
             self.write(body)
         self.finish()
+
+    def _ebRender(self, failure, resrc):
+        failure.trap(UnsupportedMethod)
+        e = failure.value
+        allowedMethods = e.allowedMethods
+        if (self.method == "HEAD") and ("GET" in allowedMethods):
+            # We must support HEAD (RFC 2616, 5.1.1).  If the
+            # resource doesn't, fake it by giving the resource
+            # a 'GET' request and then return only the headers,
+            # not the body.
+            log.msg("Using GET to fake a HEAD request for %s" %
+                    (resrc,))
+            self.method = "GET"
+            body = resrc.render(self)
+
+            if body is NOT_DONE_YET:
+                log.msg("Tried to fake a HEAD request for %s, but "
+                        "it got away from me." % resrc)
+                # Oh well, I guess we won't include the content length.
+            else:
+                self.setHeader('content-length', str(len(body)))
+
+            self.write('')
+            self.finish()
+            return
+
+        if self.method in (supportedMethods):
+            # We MUST include an Allow header
+            # (RFC 2616, 10.4.6 and 14.7)
+            self.setHeader('Allow', allowedMethods)
+            s = ('''Your browser approached me (at %(URI)s) with'''
+                 ''' the method "%(method)s".  I only allow'''
+                 ''' the method%(plural)s %(allowed) here.''' % {
+                'URI': self.uri,
+                'method': self.method,
+                'plural': ((len(allowedMethods) > 1) and 's') or '',
+                'allowed': string.join(allowedMethods, ', ')
+                })
+            epage = error.ErrorPage(http.NOT_ALLOWED,
+                                    "Method Not Allowed", s)
+            body = epage.render(self)
+        else:
+            epage = error.ErrorPage(http.NOT_IMPLEMENTED, "Huh?",
+                                    """I don't know how to treat a"""
+                                    """ %s request."""
+                                    % (self.method))
+            body = epage.render(self)
+
+    def render(self, resrc):
+        defer.maybeDeferred(resrc.render, self).addErrback(self._ebRender, resrc).addCallback(self._cbRender, resrc).addErrback(self.processingFailed)
+
+
 
     def processingFailed(self, reason):
         log.err(reason)