Issue 2180 - [cms] Add support for custom Jinja2 functions

cms/converters.py

 # coding: utf-8
 
 # This file is part of the Adblock Plus web scripts,
 # Copyright (C) 2006-2015 Eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus is distributed in the hope that it will be useful,
@@ skipping 250 matching lines @@
     filters = {
       "translate": self.translate,
       "linkify": self.linkify,
       "toclist": self.toclist,
     }
 
     globals = {
       "get_string": self.get_string,
     }
 
-    for dirname, dictionary in [("filters", filters), ("functions", globals)]:

[Sebastian Noack, 2015/03/20 09:49:43]

How about calling it "globals" as well to match the jinja2 API, and strictly
those doesn't need to be limitted to functions anyway.

Also this patch should update the README as well.

[Wladimir Palant, 2015/03/20 16:02:24]

Strictly speaking - yes, these don't need to be functions. It is hard to imagine
what else they could be however. Either way, fine with me.
Sure.

[Sebastian Noack, 2015/03/20 16:10:54]

Instances (with methods) would come to my mind.
Thanks.

+    for dirname, dictionary in [("filters", filters), ("globals", globals)]:
       for filename in self._params["source"].list_files(dirname):
         root, ext = os.path.splitext(filename)
         if ext.lower() != ".py":
           continue
 
         path = "%s/%s" % (dirname, filename)
         code = self._params["source"].read_file(path)
         module = imp.new_module(root.replace("/", "."))
         exec code in module.__dict__
 
-        func = os.path.basename(root)
-        if not hasattr(module, func):
-          raise Exception("Expected function %s not found in %s file %s" % (func, dirname, filename))
-        dictionary[func] = getattr(module, func)
-        dictionary[func].module_ref = module  # Prevent garbage collection
-
-    self._env = jinja2.Environment(
-        loader=self._SourceLoader(self._params["source"]),
-        extensions=["jinja2.ext.do",],
-        autoescape=True
-    )
+        name = os.path.basename(root)
+        if not hasattr(module, name):
+          raise Exception("Expected symbol %s not found in %s file %s" % (name, dirname, filename))
+        dictionary[name] = getattr(module, name)
+
+        # HACK: The module we created here can be garbage collected because it
+        # isn't added to sys.modules. If a function is called and its module is
+        # gone it might cause weird errors (imports and module variables
+        # unavailable). We avoid this situation by explicitly referencing the
+        # module from the function so they can only be garbage collected
+        # together.
+        if callable(dictionary[name]):
+          dictionary[name].module_ref = module
+
+    self._env = jinja2.Environment(loader=self._SourceLoader(self._params["source"]), autoescape=True)
     self._env.filters.update(filters)
     self._env.globals.update(globals)
 
   def get_html(self, source):
     template = self._env.from_string(source)
-    return template.render(self._params, params=self._params)
+    module = template.make_module(self._params)
+    for key, value in module.__dict__.iteritems():
+      if not key.startswith("_"):
+        self._params[key] = value
+    return unicode(module)
 
   def translate(self, default, name, comment=None):
     # Note: We currently ignore the comment, it is only relevant when
     # generating the master translation.
     localedata = self._params["localedata"]
     return jinja2.Markup(self.localize_string(name, default, localedata, html_escapes))
 
   def get_string(self, name, page):
     localedata = self._params["source"].read_locale(self._params["locale"], page)
     default = localedata[name]
@@ skipping 28 matching lines @@
         stack.pop()
       stack[-1]["subitems"].append(item)
       stack.append(item)
     return structured
 
 converters = {
   "html": RawConverter,
   "md": MarkdownConverter,
   "tmpl": TemplateConverter,
 }