Issue 4488 - Add support for JSON page front matter

cms/utils.py

 # This file is part of the Adblock Plus web scripts,
 # Copyright (C) 2006-present 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 70 matching lines @@
         for line in text.splitlines(True):
             if not re.search(r'^\s*[\w\-]+\s*=', line):
                 break
             name, value = line.split('=', 1)
             value = value.strip()
             if value.startswith('[') and value.endswith(']'):
                 value = [element.strip() for element in value[1:-1].split(',')]
             metadata[name.strip()] = value
             length += len(line)
 
-    # Need to preserve line numbers for jinja2 tracebacks

[Sebastian Noack, 2018/03/31 22:07:36]

This comment is slightly out of place here. Perhaps move it inside the block.
Otherwise it looks like that the check in the next line is related to preserving
line numbers too (which it is not).

[rosie, 2018/04/18 02:35:32]

Done.

     if length > 0:
+        # Need to preserve line numbers for jinja2 tracebacks
         cutoff = m.end() if m else length
         source = '\n' * source.count('\n', 0, cutoff) + source[cutoff:]
+
     return metadata, source
 
 
 def get_page_params(source, locale, page, format=None, site_url_override=None,
                     localized_string_callback=None):
     from cms.converters import converters
 
     # Guess page format if omitted, but default to Markdown for friendlier exceptions
     if format is None:
         for format in converters.iterkeys():
@@ skipping 61 matching lines @@
     return params
 
 
 def process_page(source, locale, page, format=None, site_url_override=None,
                  localized_string_callback=None):
     from cms.converters import TemplateConverter
 
     params = get_page_params(source, locale, page, format, site_url_override,
                              localized_string_callback)
     return TemplateConverter(*params['templatedata'], params=params)()