Fixed #16717 -- Added ability to store result of trans template tag in context variable.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16712 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/templatetags/i18n.py

@@ -70,8 +70,9 @@ class GetCurrentLanguageBidiNode(Node):
 
 
 class TranslateNode(Node):
-    def __init__(self, filter_expression, noop):
+    def __init__(self, filter_expression, noop, asvar=None):
         self.noop = noop
+        self.asvar = asvar
         self.filter_expression = filter_expression
         if isinstance(self.filter_expression.var, basestring):
             self.filter_expression.var = Variable(u"'%s'" % self.filter_expression.var)
@@ -79,7 +80,12 @@ class TranslateNode(Node):
     def render(self, context):
         self.filter_expression.var.translate = not self.noop
         output = self.filter_expression.resolve(context)
-        return _render_value_in_context(output, context)
+        value = _render_value_in_context(output, context)
+        if self.asvar:
+            context[self.asvar] = value
+            return ''
+        else:
+            return value
 
 
 class BlockTranslateNode(Node):
@@ -296,16 +302,21 @@ def do_translate(parser, token):
                 elif value[-1] == "'":
                     value = '"%s"' % value[1:-1].replace('"','\\"')
 
-            if self.more():
-                if self.tag() == 'noop':
-                    noop = True
-                else:
-                    raise TemplateSyntaxError("only option for 'trans' is 'noop'")
-            else:
             noop = False
-            return (value, noop)
-    value, noop = TranslateParser(token.contents).top()
-    return TranslateNode(parser.compile_filter(value), noop)
+            asvar = None
+
+            while self.more():
+                tag = self.tag()
+                if tag == 'noop':
+                    noop = True
+                elif tag == 'as':
+                    asvar = self.tag()
+                else:
+                    raise TemplateSyntaxError(
+                        "only options for 'trans' are 'noop' and 'as VAR.")
+            return (value, noop, asvar)
+    value, noop, asvar = TranslateParser(token.contents).top()
+    return TranslateNode(parser.compile_filter(value), noop, asvar)
 
 @register.tag("blocktrans")
 def do_block_translate(parser, token):

docs/releases/1.4.txt

@@ -283,6 +283,10 @@ Django 1.4 also includes several smaller improvements worth noting:
   about :ref:`the 403 (HTTP Forbidden) view<http_forbidden_view>` for more
   information.
 
+* The :ttag:`trans` template tag now takes an optional ``as`` argument to
+  be able to retrieve a translation string without displaying it but setting
+  a template context variable instead.
+
 .. _backwards-incompatible-changes-1.4:
 
 Backwards incompatible changes in 1.4

docs/topics/i18n/internationalization.txt

@@ -451,6 +451,32 @@ It's not possible to mix a template variable inside a string within ``{% trans
 %}``. If your translations require strings with variables (placeholders), use
 ``{% blocktrans %}`` instead.
 
+.. versionchanged:: 1.4
+
+If you'd like to retrieve a translated string without displaying it, you can
+use the following syntax::
+
+    {% trans "This is the title" as the_title %}
+
+    <title>{{ the_title }}</title>
+    <meta name="description" content="{{ the_title }}">
+
+In practice you'll use this to get strings that are used in multiple places
+or should be used as arguments for other template tags or filters::
+
+    {% trans "starting point" as start %}
+    {% trans "end point" as end %}
+    {% trans "La Grande Boucle" as race %}
+
+    <h1>
+      <a href="/" title="{% blocktrans %}Back to '{{ race }}' homepage{% endblocktrans %}">{{ race }}</a>
+    </h1>
+    <p>
+    {% for stage in tour_stages %}
+        {% cycle start end %}: {{ stage }}{% if forloop.counter|divisibleby:2 %}<br />{% else %}, {% endif %}
+    {% endfor %}
+    </p>
+
 .. templatetag:: blocktrans
 
 ``blocktrans`` template tag

tests/regressiontests/templates/tests.py

@@ -1294,6 +1294,12 @@ class Templates(unittest.TestCase):
             # blocktrans handling of variables which are not in the context.
             'i18n34': ('{% load i18n %}{% blocktrans %}{{ missing }}{% endblocktrans %}', {}, u''),
 
+            # trans tag with as var
+            'i18n35': ('{% load i18n %}{% trans "Page not found" as page_not_found %}{{ page_not_found }}', {'LANGUAGE_CODE': 'de'}, "Seite nicht gefunden"),
+            'i18n36': ('{% load i18n %}{% trans "Page not found" noop as page_not_found %}{{ page_not_found }}', {'LANGUAGE_CODE': 'de'}, "Page not found"),
+            'i18n36': ('{% load i18n %}{% trans "Page not found" as page_not_found noop %}{{ page_not_found }}', {'LANGUAGE_CODE': 'de'}, "Page not found"),
+            'i18n37': ('{% load i18n %}{% trans "Page not found" as page_not_found %}{% blocktrans %}Error: {{ page_not_found }}{% endblocktrans %}', {'LANGUAGE_CODE': 'de'}, "Error: Seite nicht gefunden"),
+
             ### HANDLING OF TEMPLATE_STRING_IF_INVALID ###################################
 
             'invalidstr01': ('{{ var|default:"Foo" }}', {}, ('Foo','INVALID')),