Issue 5044 - Support absolute paths for Jinja templates

sitescripts/utils.py

 # This file is part of the Adblock Plus web scripts,
 # Copyright (C) 2006-2017 eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus 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
@@ skipping 128 matching lines @@
     try:
         return email.encode('ascii')
     except UnicodeEncodeError:
         return '%s@%s' % (match.group(1).encode('ascii'),
                           match.group(2).encode('idna'))
 
 _template_cache = {}
 
 
 def get_template(template, autoescape=True, template_path=siteScriptsPath):
-    """Parses and returns a Jinja2 template"""
+    """Load Jinja2 template.
+
+    If `template` is a relative path, it's looked up inside `template_path`.
+    If it's an absolute path, `template_path` is not used.
+
+    Note: Each template will only be loaded once (when first requested). After
+    that it will be cached and reused -- any changes on the filesystem will be
+    ignored.
+    """
+    if os.path.isabs(template):
+        template_path, template = os.path.split(template)
+    template_path = os.path.abspath(template_path)
     key = (template_path, template, autoescape)
-    if not key in _template_cache:
+    if key not in _template_cache:
         if autoescape:
             env = get_template_environment(template_path)
         else:
             env = get_unescaped_template_environment(template_path)
         _template_cache[key] = env.get_template(template)
     return _template_cache[key]
 
 
 @cached(float('inf'))
 def get_template_environment(template_path):
@@ skipping 26 matching lines @@
       Returns a custom Jinja2 template environment with additional filters.
     """
     from sitescripts.templateFilters import filters
     import jinja2
     if not loader:
         loader = jinja2.FileSystemLoader(siteScriptsPath)
     env = jinja2.Environment(loader=loader, autoescape=True)
     env.filters.update(filters)
     env.filters.update(additional_filters)
     return env