Ticket #2778: includeblock.patch

django/template/loader_tags.py

@@ -1 @@
-from django.template import TemplateSyntaxError, TemplateDoesNotExist, resolve_variable
+from django.template import TemplateSyntaxError, TemplateDoesNotExist, VariableDoesNotExist, resolve_variable
 from django.template import Library, Node
 from django.template.loader import get_template, get_template_from_string, find_template_source
 from django.conf import settings
@@ -113 +113 @@
         except:
             return '' # Fail silently for invalid included templates.
 
+class IncludeBlockNode(Node):
+    def __init__(self, template_name, block_name, template_dirs=None):
+        self.template_name = template_name
+        self.block_name = block_name
+        self.template_dirs = template_dirs
+
+    def render(self, context):
+        try:
+            template_name = resolve_variable(self.template_name, context)
+            block_name = resolve_variable(self.block_name, context)
+        except VariableDoesNotExist:
+            # Fail silently if either variable can not be resolved.
+            return ''
+        try:
+            template = get_template(template_name)
+        except TemplateSyntaxError, e:
+            if settings.TEMPLATE_DEBUG:
+                raise
+            return ''
+        except:
+            return '' # Fail silently for invalid included template.
+        for block_node in template.nodelist.get_nodes_by_type(BlockNode):
+            if block_name == block_node.name:
+                # Block matches, render it.
+                return block_node.render(context)
+        # No matching block was found.
+        return ''
+
 def do_block(parser, token):
     """
     Define a block that can be overridden by child templates.
@@ -172 +200 @@
         return ConstantIncludeNode(path[1:-1])
     return IncludeNode(bits[1])
 
+def do_includeblock(parser, token):
+    """
+    Loads a block from another template and renders it with the current 
+    context. The first argument is the template name, the second is the block.
+    Both can be variables rendered from the context or given as constants by
+    surrounding with quotes.
+    
+    Example::
+    
+        {% includeblock "foo/some_include.htm" "bar_block" %}
+    """
+    bits = token.split_contents()
+    if len(bits) != 3:
+        raise TemplateSyntaxError, "%r tag takes two arguments: the name of the template and the block to be included" % bits[0]
+    return IncludeBlockNode(*bits[1:])
+
 register.tag('block', do_block)
 register.tag('extends', do_extends)
 register.tag('include', do_include)
+register.tag('includeblock', do_includeblock)

docs/templates.txt

@@ -577 +577 @@
 
 See also: ``{% ssi %}``.
 
+includeblock
+~~~~~~~~~~~~
+
+Similar to ``include`` but rather than rendering the entire template, this
+renders a specific ``block`` of the given template with the current context.
+
+Both the template name and the block name can either be variables or
+hard-coded (quoted) strings.
+
+This example includes the "navigation" block of the template "main.htm"::
+
+        {% includeblock "main.htm" "navigation" %}
+
 load
 ~~~~
 

tests/regressiontests/templates/tests.py

@@ -418 +418 @@
             # Inheritance from local context with variable parent template
             'inheritance25': ("{% extends context_template.1 %}{% block first %}2{% endblock %}{% block second %}4{% endblock %}", {'context_template': [template.Template("Wrong"), template.Template("1{% block first %}_{% endblock %}3{% block second %}_{% endblock %}")]}, '1234'),
 
+            ### INCLUDEBLOCK TAG ######################################################
+            
+            # Loading a block tag
+            'includeblock01': ('1{% includeblock "inheritance02" "first" %}3', {}, '123'),
+            
+            # Loading a block tag using the template name as a context variable
+            'includeblock02': ('3{% includeblock template_name "second" %}5', {'template_name': 'inheritance02'}, '345'),
+
+            # Loading a block tag using the block name as a context variable
+            'includeblock03': ('3{% includeblock "inheritance02" block_name %}5', {'block_name': 'second'}, '345'),
+
+            # Loading a block tag using context variables
+            'includeblock04': ('3{% includeblock template_name block_name %}5', {'template_name': 'inheritance02', 'block_name': 'second'}, '345'),
+
+            # Invalid template
+            'includeblock05': ('a{% includeblock "not a real template" "blockname" %}b', {}, 'ab'),
+            
+            # Invalid block
+            'includeblock06': ('b{% includeblock "inheritance02" "invalidblockname" %}c', {}, 'bc'),
+            
+            # Invalid template context variable
+            'includeblock07': ('a{% includeblock invalidtemplatename "blockname" %}b', {}, 'ab'),
+            
+            # Invalid block context variable
+            'includeblock08': ('b{% includeblock "inheritance02" invalidblockname %}c', {}, 'bc'),
+            
             ### I18N ##################################################################
 
             # {% spaceless %} tag