Jinja2 Dependency Detection

jinja_deps.py

"""Test how the Jinja templates"""

import os
import jinja2
from jinja2.ext import Extension

class DependenciesExt(Extension):
    """This extension attempts to track the dependencies used in a template."""

    def filter_stream(self, stream):
        current_token = None
        for token in stream:
            if not current_token:
                if token.type == 'name':
                    if token.value in ['include', 'extends']:
                        current_token = token.value
                        print 'start: {}'.format(token.value)
            elif current_token == 'include':
                if token.type == 'name':
                    print '{} :: {}'.format(current_token, token.value)
                    current_token = None
                if token.type == 'block_end':
                    current_token = None
            elif current_token == 'extends':
                if token.type == 'string':
                    print '{} :: {}'.format(current_token, token.value)
                    current_token = None
            yield token

if __name__ == "__main__":
    base_path = os.path.dirname(os.path.realpath(__file__))
    jinja_env = jinja2.Environment(
        loader=jinja2.FileSystemLoader(base_path))

    template = jinja_env.get_template('template.html')
    print template.render({
        "partials": [
            "test1.html",
            "test2.html",
        ],
    })

template.html

{% for partial in partials %}
    {% include partial %}
{% endfor %}

test1.html

Test 1!

test2.html

Test 2!

I've actually managed to pull this (or very close) off using jinja2.meta.find_referenced_templates(), overriding my fsloader and intercepting the source there. A working (and ugly) example:

class MFSLoader(FileSystemLoader):
	dependencies = {}
	def get_source(self, environment, template):
		source, filename, uptodate = super(MFSLoader, self).get_source(environment, template)
		dependencies = jinjameta.find_referenced_templates(environment.parse(source))
		if filename not in dependencies:
			self.dependencies[filename] = set()
		self.dependencies[filename].update(dependencies)
		return source, filename, uptodate