third_party/markdown/postprocessors.py

   1 # markdown is released under the BSD license
   2 # Copyright 2007, 2008 The Python Markdown Project (v. 1.7 and later)
   3 # Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
   4 # Copyright 2004 Manfred Stienstra (the original version)
   5 #
   6 # All rights reserved.
   7 #
   8 # Redistribution and use in source and binary forms, with or without
   9 # modification, are permitted provided that the following conditions are met:
  10 #
  11 # *   Redistributions of source code must retain the above copyright
  12 #     notice, this list of conditions and the following disclaimer.
  13 # *   Redistributions in binary form must reproduce the above copyright
  14 #     notice, this list of conditions and the following disclaimer in the
  15 #     documentation and/or other materials provided with the distribution.
  16 # *   Neither the name of the <organization> nor the
  17 #     names of its contributors may be used to endorse or promote products
  18 #     derived from this software without specific prior written permission.
  19 #
  20 # THIS SOFTWARE IS PROVIDED BY THE PYTHON MARKDOWN PROJECT ''AS IS'' AND ANY
  21 # EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  22 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  23 # DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTORS TO THE PYTHON MARKDOWN PROJECT
  24 # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25 # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26 # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27 # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28 # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  29 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  30 # POSSIBILITY OF SUCH DAMAGE.
  31
  32
  33 """
  34 POST-PROCESSORS
  35 =============================================================================
  36
  37 Markdown also allows post-processors, which are similar to preprocessors in
  38 that they need to implement a "run" method. However, they are run after core
  39 processing.
  40
  41 """
  42
  43 from __future__ import absolute_import
  44 from __future__ import unicode_literals
  45 from . import util
  46 from . import odict
  47 import re
  48
  49
  50 def build_postprocessors(md_instance, **kwargs):
  51     """ Build the default postprocessors for Markdown. """
  52     postprocessors = odict.OrderedDict()
  53     postprocessors["raw_html"] = RawHtmlPostprocessor(md_instance)
  54     postprocessors["amp_substitute"] = AndSubstitutePostprocessor()
  55     postprocessors["unescape"] = UnescapePostprocessor()
  56     return postprocessors
  57
  58
  59 class Postprocessor(util.Processor):
  60     """
  61     Postprocessors are run after the ElementTree it converted back into text.
  62
  63     Each Postprocessor implements a "run" method that takes a pointer to a
  64     text string, modifies it as necessary and returns a text string.
  65
  66     Postprocessors must extend markdown.Postprocessor.
  67
  68     """
  69
  70     def run(self, text):
  71         """
  72         Subclasses of Postprocessor should implement a `run` method, which
  73         takes the html document as a single text string and returns a
  74         (possibly modified) string.
  75
  76         """
  77         pass
  78
  79
  80 class RawHtmlPostprocessor(Postprocessor):
  81     """ Restore raw html to the document. """
  82
  83     def run(self, text):
  84         """ Iterate over html stash and restore "safe" html. """
  85         for i in range(self.markdown.htmlStash.html_counter):
  86             html, safe  = self.markdown.htmlStash.rawHtmlBlocks[i]
  87             if self.markdown.safeMode and not safe:
  88                 if str(self.markdown.safeMode).lower() == 'escape':
  89                     html = self.escape(html)
  90                 elif str(self.markdown.safeMode).lower() == 'remove':
  91                     html = ''
  92                 else:
  93                     html = self.markdown.html_replacement_text
  94             if self.isblocklevel(html) and (safe or not self.markdown.safeMode):
  95                 text = text.replace("<p>%s</p>" %
  96                             (self.markdown.htmlStash.get_placeholder(i)),
  97                             html + "\n")
  98             text =  text.replace(self.markdown.htmlStash.get_placeholder(i),
  99                                  html)
 100         return text
 101
 102     def escape(self, html):
 103         """ Basic html escaping """
 104         html = html.replace('&', '&amp;')
 105         html = html.replace('<', '&lt;')
 106         html = html.replace('>', '&gt;')
 107         return html.replace('"', '&quot;')
 108
 109     def isblocklevel(self, html):
 110         m = re.match(r'^\<\/?([^ >]+)', html)
 111         if m:
 112             if m.group(1)[0] in ('!', '?', '@', '%'):
 113                 # Comment, php etc...
 114                 return True
 115             return util.isBlockLevel(m.group(1))
 116         return False
 117
 118
 119 class AndSubstitutePostprocessor(Postprocessor):
 120     """ Restore valid entities """
 121
 122     def run(self, text):
 123         text =  text.replace(util.AMP_SUBSTITUTE, "&")
 124         return text
 125
 126
 127 class UnescapePostprocessor(Postprocessor):
 128     """ Restore escaped chars """
 129
 130     RE = re.compile('%s(\d+)%s' % (util.STX, util.ETX))
 131
 132     def unescape(self, m):
 133         return util.int2str(int(m.group(1)))
 134
 135     def run(self, text):
 136         return self.RE.sub(self.unescape, text)