# Copyright 2020 Karlsruhe Institute of Technology
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from flask import render_template
from jinja2 import nodes
from jinja2.ext import Extension
[docs]class SnippetExtension(Extension):
"""Jinja extension to pass variables to HTML snippets.
See :func:`render_snippet` for an explanation of the parameters.
**Example:**
.. code-block:: jinja
{% snippet "my_snippet", foo=1, bar=2 %}
"""
tags = {"snippet"}
[docs] def parse(self, parser):
"""Parse the snippet tag and arguments."""
kwargs = []
# Token that started the tag.
tag = next(parser.stream)
# Parse the snippet name.
name = parser.parse_expression()
if parser.stream.skip_if("comma"):
# Parse the key/value-arguments.
while parser.stream.current.type != "block_end":
if kwargs:
parser.stream.expect("comma")
key = next(parser.stream)
key = nodes.Const(key.value, lineno=key.lineno)
parser.stream.expect("assign")
value = parser.parse_expression()
kwargs.append(nodes.Pair(key, value, lineno=key.lineno))
return nodes.CallBlock(
self.call_method("_render_snippet", [name, nodes.Dict(kwargs)]), [], [], []
).set_lineno(tag.lineno)
def _render_snippet(self, name, kwargs, caller):
return render_snippet(name, **kwargs)
[docs]def render_snippet(snippet, _module=None, **kwargs):
r"""Render an HTML snippet.
The snippet has to be in a directory called "snippets". Otherwise, the same rules
apply as in Flask's ``render_template`` function.
:param snippet: The name of the snippet without the ".html" extension.
:param _module: (optional) If the snippet is part of a module, the name of this
module can be specified using this parameter. It will be prepended before the
snippet path.
:param \**kwargs: The keyword arguments to pass to the snippet.
:return: The rendered snippet.
"""
module = f"{_module}/" if _module else ""
return render_template([f"{module}snippets/{snippet}.html"], **kwargs)