Changes between Version 2 and Version 3 of GenshiRecipes/Localization

Timestamp:

Nov 9, 2006, 2:39:43 PM (17 years ago)

Author:

David Fraser <davidf@…>

Comment:

added derived localization template classes

GenshiRecipes/Localization

@@ -268 +268 @@
 
 }}}
+
+== Page Generation with Localized Templates ==
+
+In order to use the modified Template stream, we basically need to do some processing before the normal Genshi mechanism takes over...
+
+This class allows inclusion of "prefilters" that operate before the Template stream's standard filters (you can't just use a filter to do this, it causes problems):
+{{{
+#!python
+class PrefilterMarkupTemplate(genshi.template.MarkupTemplate):
+    """Derived markup template that can receive prefilters in its generate method"""
+    # TODO: try and upstream this into genshi
+    def generate(self, prefilters, *args, **kwargs):
+        """Apply the template to the given context data.
+        
+        Any keyword arguments are made available to the template as context
+        data.
+        
+        Only one positional argument is accepted: if it is provided, it must be
+        an instance of the `Context` class, and keyword arguments are ignored.
+        This calling style is used for internal processing.
+        
+        @return: a markup event stream representing the result of applying
+            the template to the context data.
+        """
+        if args:
+            assert len(args) == 1
+            ctxt = args[0]
+            if ctxt is None:
+                ctxt = genshi.template.Context(**kwargs)
+            assert isinstance(ctxt, genshi.template.Context)
+        else:
+            ctxt = genshi.template.Context(**kwargs)
+
+        stream = self.stream
+        for prefilter in prefilters:
+            # TODO: add support for context in prefilters
+            stream = prefilter(iter(stream))
+        for filter_ in self.filters:
+            stream = filter_(iter(stream), ctxt)
+        return genshi.core.Stream(stream)
+}}
+
+This derived class then allows you to call the above localization function as a prefilter on templates. It uses the domain_name as a parameter (this corresponds to which PO/MO file to use for translation, but assumes you can construct or retrieve a translation object for the current user on the fly using a get_translation function (not described here):
+{{
+#!python
+class LocalizeMarkupTemplate(PrefilterMarkupTemplate):
+    """Derived markup template that can handle localizing before stream generation"""
+    def __init__(self, source, basedir=None, filename=None, loader=None,
+                 encoding=None, domain_name=None):
+        """Initialize a template from either a string or a file-like object."""
+        super(LocalizeMarkupTemplate, self).__init__(source, basedir=basedir, filename=filename, loader=loader, encoding=encoding)
+        self.domain_name = domain_name
+
+    def localize_prefilter(self, stream):
+        """prefilter for localizing..."""
+        translation = get_translation(self.domain_name)
+        stream = genshi.core.Stream(stream)
+        localized_stream = genshigettext.localize_template(stream, translation.ugettext)
+        return list(iter(localized_stream))
+
+    # TODO: try and persuade genshi to accept a stream directly here instead of using self.stream - or accept prefilters
+    # then we won't use such fragile copied code...
+    def generate(self, prefilters, *args, **kwargs):
+        """Apply the template to the given context data.
+        
+        Any keyword arguments are made available to the template as context
+        data.
+        
+        Only one positional argument is accepted: if it is provided, it must be
+        an instance of the `Context` class, and keyword arguments are ignored.
+        This calling style is used for internal processing.
+        
+        @return: a markup event stream representing the result of applying
+            the template to the context data.
+        """
+        return super(LocalizeMarkupTemplate, self).generate(prefilters + [self.localize_prefilter], *args, **kwargs)
+}}