No replacement for ITemplateStreamFilter

[Dirk Stöcker]

Trac 1.6 dropped the ITemplateStreamFilter from Genshi completely and I'm unable to find ANY replacement to use in spamfilter for the trapfield strategy.

That strategy is one of the major contributors to reject spam.

Please create a new method to access the final templated string

• a callback for template conversion
• an Extension which hooks before the the call to req.send()
• an extension to Request to hook into _send()
• a possible to extend/override the Request class (probably the best solution with most options for different use)

If there is something I overlooked please tell me. I didn't find anything relevant.

[Dirk Stöcker]

A possible solution could look like this:

web/chrome.py

@@ -120 +120 @@
         files.
         """
 
+class ITemplateModifier(Interface):
+    """Extension point interface for components that modify Jinja2 templates.
+    """
+
+    def pre_modify_template(req, template, data, metadata):
+        """Return True or False in case post function should be called or not
+
+        Arguments are the request, the template, data for the template and
+        the metadata.
+        """
+
+    def post_modify_template(req, template, data, stream):
+        """Returns the stream again or a replacement for it
+
+        Arguments are the request, the template and the data for it as
+        well as the stream of the generated template.
+
+        Function is only called when pre function returned True
+        """
 
 def accesskey(req, key):
     """Helper function for creating accesskey HTML attribute according
@@ -419 +438 @@
 
     navigation_contributors = ExtensionPoint(INavigationContributor)
     template_providers = ExtensionPoint(ITemplateProvider)
+    template_modifiers = ExtensionPoint(ITemplateModifier)
 
     shared_templates_dir = PathOption('inherit', 'templates_dir', '',
         """Path to the //shared templates directory//.
@@ -1380 +1400 @@
 
         template, data = self.prepare_template(req, filename, data, text,
                                                domain)
+        mods = []
+        for mod in self.template_modifiers:
+            if mod.pre_modify_template(req, template, data, metadata):
+                mods.append(mod)
 
         # TODO (1.5.1) - have another try at simplifying all this...
         # With Jinja2, it's certainly possible to do things
@@ -1399 +1423 @@
 
         if fragment or text:
             if iterable:
-                return self.generate_template_stream(template, data, text,
+                return self.generate_template_stream(req, mods, template, data, text,
                                                      iterable)
             else:
                 s = self.render_template_string(template, data, text)
@@ -1408 +1432 @@
         data['chrome']['content_type'] = content_type
 
         try:
-            return self.generate_template_stream(template, data, text,
+            return self.generate_template_stream(req, mods, template, data, text,
                                                  iterable)
         except Exception:
             # restore what may be needed by the error template
@@ -1437 +1461 @@
         """
         template, data = self.prepare_template(req, filename, data, text,
                                                domain)
-        return self.generate_template_stream(template, data, text)
+        return self.generate_template_stream(req, [], template, data, text)
 
     def render_fragment(self, req, filename, data, text=False, domain=None):
         """Produces a string from given template *filename* and input *data*,
@@ -1489 +1513 @@
         data = self.populate_data(req, data)
         return template, data
 
-    def generate_template_stream(self, template, data, text=False,
+    def generate_template_stream(self, req, mods, template, data, text=False,
                                  iterable=None):
         """Returns the rendered template in a form that can be "sent".
 
@@ -1519 +1543 @@
         """
         stream = template.stream(data)
         stream.enable_buffering(75)  # buffer_size
+        for mod in mods:
+            stream = mod.post_modify_template(req, template, data, stream)
         if iterable or iterable is None and self.use_chunked_encoding:
             return self.iterable_content(stream, text)
         else:

[Dirk Stöcker]

In #13321 there was another solution which works.