Fixed #2606 -- Added tag for working out the URL of a particular view function.

All work done by Ivan Sagalaev.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@4494 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/template/defaulttags.py

@@ -315,6 +315,25 @@ class TemplateTagNode(Node):
     def render(self, context):
         return self.mapping.get(self.tagtype, '')
 
+class URLNode(Node):
+    def __init__(self, view_name, args, kwargs):
+        self.view_name = view_name
+        self.args = args
+        self.kwargs = kwargs
+      
+    def render(self, context):
+        from django.core.urlresolvers import reverse, NoReverseMatch
+        args = [arg.resolve(context) for arg in self.args]
+        kwargs = dict([(k, v.resolve(context)) for k, v in self.kwargs.items()])
+        try:
+            return reverse(self.view_name, args=args, kwargs=kwargs)
+        except NoReverseMatch:
+            try:
+                project_name = settings.SETTINGS_MODULE.split('.')[0]
+                return reverse(project_name + '.' + self.view_name, args=args, kwargs=kwargs)
+            except NoReverseMatch:
+                return ''
+
 class WidthRatioNode(Node):
     def __init__(self, val_expr, max_expr, max_width):
         self.val_expr = val_expr
@@ -868,6 +887,50 @@ def templatetag(parser, token):
     return TemplateTagNode(tag)
 templatetag = register.tag(templatetag)
 
+def url(parser, token):
+    """
+    Returns an absolute URL matching given view with its parameters. This is a
+    way to define links that aren't tied to a particular url configuration:
+    
+        {% url path.to.some_view arg1,arg2,name1=value1 %}
+    
+    The first argument is a path to a view. It can be an absolute python path
+    or just ``app_name.view_name`` without the project name if the view is
+    located inside the project.  Other arguments are comma-separated values
+    that will be filled in place of positional and keyword arguments in the
+    URL. All arguments for the URL should be present.
+
+    For example if you have a view ``app_name.client`` taking client's id and
+    the corresponding line in a urlconf looks like this:
+    
+        ('^client/(\d+)/$', 'app_name.client')
+    
+    and this app's urlconf is included into the project's urlconf under some
+    path:
+    
+        ('^clients/', include('project_name.app_name.urls'))
+    
+    then in a template you can create a link for a certain client like this:
+    
+        {% url app_name.client client.id %}
+    
+    The URL will look like ``/clients/client/123/``.
+    """
+    bits = token.contents.split(' ', 2)
+    if len(bits) < 2:
+        raise TemplateSyntaxError, "'%s' takes at least one argument (path to a view)" % bits[0]
+    args = []
+    kwargs = {}
+    if len(bits) > 2:
+        for arg in bits[2].split(','):
+            if '=' in arg:
+                k, v = arg.split('=', 1)
+                kwargs[k] = parser.compile_filter(v)
+            else:
+                args.append(parser.compile_filter(arg))
+    return URLNode(bits[1], args, kwargs)
+url = register.tag(url)
+
 #@register.tag
 def widthratio(parser, token):
     """

docs/templates.txt

@@ -829,6 +829,40 @@ The argument tells which template bit to output:
 
 Note: ``opencomment`` and ``closecomment`` are new in the Django development version.
 
+url
+~~~
+
+Returns an absolute URL matching a given view function. This is a way to
+define links that aren't tied to a particular url configuration.
+
+::
+
+    {% url path.to.some_view arg1,arg2,name1=value1 %}
+
+The first argument is a path to a view function. It can be an absolute python
+path or just ``app_name.view_name`` without the project name if the view is
+located inside the project.  Other arguments are comma-separated values that
+will be use as positional and keyword arguments in the URL. All arguments
+needed by the URL resolver should be present.
+
+For example, suppose you have a view ``app_name.client`` taking client's id
+and the corresponding line in a urlconf looks like this::
+
+    ('^client/(\d+)/$', 'app_name.client')
+
+If this app's urlconf is included into the project's urlconf under a path
+such as
+
+::
+
+    ('^clients/', include('project_name.app_name.urls'))
+
+then, in a template, you can create a link to this view like this::
+
+    {% url app_name.client client.id %}
+
+The URL rendered in the template will then look like ``/clients/client/123/``.
+
 widthratio
 ~~~~~~~~~~
 

tests/regressiontests/templates/tests.py

@@ -645,6 +645,17 @@ class Templates(unittest.TestCase):
             # Compare to a given parameter
             'timeuntil04' : ('{{ a|timeuntil:b }}', {'a':NOW - timedelta(days=1), 'b':NOW - timedelta(days=2)}, '1 day'),
             'timeuntil05' : ('{{ a|timeuntil:b }}', {'a':NOW - timedelta(days=2), 'b':NOW - timedelta(days=2, minutes=1)}, '1 minute'),
+
+            ### URL TAG ########################################################
+            # Successes
+            'url01' : ('{% url regressiontests.templates.views.client client.id %}', {'client': {'id': 1}}, '/url_tag/client/1/'),
+            'url02' : ('{% url regressiontests.templates.views.client_action client.id,action="update" %}', {'client': {'id': 1}}, '/url_tag/client/1/update/'),
+            'url03' : ('{% url regressiontests.templates.views.index %}', {}, '/url_tag/'),
+
+            # Failures
+            'url04' : ('{% url %}', {}, template.TemplateSyntaxError),
+            'url05' : ('{% url no_such_view %}', {}, ''),
+            'url06' : ('{% url regressiontests.templates.views.client no_such_param="value" %}', {}, ''),
         }
 
         # Register our custom template loader.

tests/regressiontests/templates/urls.py

@@ -0,0 +1,10 @@
+from django.conf.urls.defaults import *
+from regressiontests.templates import views
+
+urlpatterns = patterns('',
+
+    # Test urls for testing reverse lookups
+    (r'^$', views.index),
+    (r'^client/(\d+)/$', views.client),
+    (r'^client/(\d+)/(?P<action>[^/]+)/$', views.client_action),
+)

tests/regressiontests/templates/views.py

@@ -0,0 +1,10 @@
+# Fake views for testing url reverse lookup
+
+def index(request):
+    pass
+
+def client(request, id):
+    pass
+
+def client_action(request, id, action):
+    pass

tests/urls.py

@@ -7,4 +7,7 @@ urlpatterns = patterns('',
     # Always provide the auth system login and logout views
     (r'^accounts/login/$', 'django.contrib.auth.views.login', {'template_name': 'login.html'}),
     (r'^accounts/logout/$', 'django.contrib.auth.views.login'),
+
+    # test urlconf for {% url %} template tag
+    (r'^url_tag/', include('regressiontests.templates.urls')),
 )