django.py 文件源码

def django_render_block(template, block_name, context):
    # Create a Django Context.
    context_instance = Context(context)

    # Get the underlying django.template.base.Template object.
    template = template.template

    # Bind the template to the context.
    with context_instance.bind_template(template):
        # Before trying to render the template, we need to traverse the tree of
        # parent templates and find all blocks in them.
        parent_template = _build_block_context(template, context_instance)

        try:
            return _render_template_block(template, block_name, context_instance)
        except BlockNotFound:
            # The block wasn't found in the current template.

            # If there's no parent template (i.e. no ExtendsNode), re-raise.
            if not parent_template:
                raise

            # Check the parent template for this block.
            return _render_template_block(
                parent_template, block_name, context_instance)