##
#
# Copyright (C) 2018 Matt Molyneaux
#
# This file is part of Exhibition.
#
# Exhibition is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Exhibition is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Exhibition. If not, see <https://www.gnu.org/licenses/>.
#
##
"""
Jinja2 template filter
To use, add the following to your configuration file:
.. code-block:: yaml
filter: exhibition.filters.jinja2
"""
from datetime import datetime, timezone
from jinja2 import Environment, FileSystemLoader, contextfilter
from jinja2.exceptions import TemplateRuntimeError
from jinja2.ext import Extension
from jinja2.nodes import CallBlock, Const, ContextReference
from markdown import markdown as md_func
from pypandoc import convert_text as pandoc_func
from typogrify.templatetags import jinja_filters as typogrify_filters
EXTENDS_TEMPLATE_TEMPLATE = """{%% extends "%s" %%}
"""
START_BLOCK_TEMPLATE = """{%% block %s %%}
"""
END_BLOCK_TEMPLATE = """{% endblock %}
"""
DEFAULT_GLOB = "*.html"
NODE_TMPL_VAR = "node"
DEFAULT_MD_KWARGS = {
"output_format": "html5",
}
DEFAULT_PANDOC_KWARGS = {
"to": "html",
}
[docs]@contextfilter
def markdown(ctx, text):
kwargs = DEFAULT_MD_KWARGS.copy()
node = ctx[NODE_TMPL_VAR]
kwargs.update(node.meta.get("markdown_config", {}))
return md_func(text, **kwargs)
[docs]@contextfilter
def pandoc(ctx, text, fmt=None):
kwargs = DEFAULT_PANDOC_KWARGS.copy()
node = ctx[NODE_TMPL_VAR]
kwargs.update(node.meta.get("pandoc_config", {}))
if fmt is not None:
kwargs["format"] = fmt
return pandoc_func(text, **kwargs)
[docs]class RaiseError(Extension):
"""
Raise an exception during template rendering:
.. code-block:: jinja
{% raise "This is an error" %}
"""
tags = set(["raise"])
def _raise_error(self, message, caller):
raise TemplateRuntimeError(message)
[docs] def parse(self, parser):
lineno = next(parser.stream).lineno
message = parser.parse_expression()
return CallBlock(
self.call_method('_raise_error', [message], lineno=lineno),
[], [], []).set_lineno(lineno)
[docs]class Mark(Extension):
"""
Marks a section for use later:
.. code-block:: html+jinja
{% mark intro %}
<p>My Intro</p>
{% endmark %}
<p>Some more text</p>
This can then be referenced via :attr:`Node.marks`.
"""
tags = set(['mark'])
[docs] def parse(self, parser):
token = next(parser.stream)
lineno = token.lineno
tag = token.value
name = next(parser.stream).value
body = parser.parse_statements(["name:end%s" % tag], drop_needle=True)
return CallBlock(self.call_method('_render_output', args=[ContextReference(), Const(name)]),
[], [], body).set_lineno(lineno)
def _render_output(self, ctx, name, caller):
"""
Assign the marked content to :attr:`Node.marks`
"""
out = caller()
ctx[NODE_TMPL_VAR].marks[name] = out
return out
[docs]def content_filter(node, content):
"""
This is the actual content filter called by :class:`exhibition.main.Node`
on appropiate nodes.
:param node:
The node being rendered
:param content:
The content of the node, stripped of any YAML frontmatter
"""
env = Environment(
loader=FileSystemLoader(node.meta["templates"]),
extensions=[RaiseError, Mark],
autoescape=True,
)
env.filters["pandoc"] = pandoc
env.filters["markdown"] = markdown
env.filters["metasort"] = metasort
env.filters["metaselect"] = metaselect
env.filters["metareject"] = metareject
typogrify_filters.register(env)
parts = []
if node.meta.get("extends"):
parts.append(EXTENDS_TEMPLATE_TEMPLATE % node.meta["extends"])
if node.meta.get("default_block"):
parts.extend([
START_BLOCK_TEMPLATE % node.meta["default_block"],
content,
END_BLOCK_TEMPLATE,
])
else:
parts.append(content)
content = "".join(parts)
template = env.from_string(content)
return template.render({
NODE_TMPL_VAR: node,
"time_now": datetime.now(timezone.utc),
})