HTMLParser chokes on bad end tag in comment

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  • Rene Pijlman
    #1

    HTMLParser chokes on bad end tag in comment

    The code below results in an exception (Python 2.4.2):

    HTMLParser.HTML ParseError: bad end tag: "</foo' + 'bar>", at line 4,
    column 6

    Should it? The end tag it chokes on is in comment, isn't it?

    import HTMLParser
    HTMLParser.HTML Parser().feed(" ""
    <html><head><ti tle></title></head><body><scr ipt>
    <!--
    x = '</foo' + 'bar>'
    // -->
    </script></body></html>
    """)

    --
    René Pijlman
    Tags: None
    • Fredrik Lundh
      #2
      Re: HTMLParser chokes on bad end tag in comment

      Rene Pijlman wrote:
      [color=blue]
      > The code below results in an exception (Python 2.4.2):
      >
      > HTMLParser.HTML ParseError: bad end tag: "</foo' + 'bar>", at line 4,
      > column 6
      >
      > Should it? The end tag it chokes on is in comment, isn't it?[/color]

      no. STYLE and SCRIPT elements contain character data, not parsed
      character data, so comments are treated as characters, and the first
      "</" ends the element.

      if you have broken documents, you can tweak this by setting the
      CDATA_CONTENT_E LEMENTS parser attribute before you start parsing.

      </F>

        Comment

        • Rene Pijlman
          #3
          Re: HTMLParser chokes on bad end tag in comment

          Fredrik Lundh:[color=blue]
          >Rene Pijlman:
          >[end tag in html comment in script element]
          >The end tag it chokes on is in comment, isn't it?
          >
          >no. STYLE and SCRIPT elements contain character data, not parsed
          >character data, so comments are treated as characters, and the first
          >"</" ends the element.[/color]

          Ah, I see. I'll report the problem to the application that's generating
          this broken code (vBulletin forum)...
          [color=blue]
          >if you have broken documents, you can tweak this by setting the
          >CDATA_CONTENT_ ELEMENTS parser attribute before you start parsing.[/color]

          .... and in the mean time that's a good workaround.

          Thank you very much Fredrik.

          --
          René Pijlman

            Comment

            • Miki
              #4
              Re: HTMLParser chokes on bad end tag in comment

              Hello Rene,

              You can also check out BeautifulSoup
              (http://www.crummy.com/software/BeautifulSoup/) which is less strict
              than the regular HTML parser.

              HTH,
              Miki
              PythonWise
              http://pythonwise.blogspot.com/
              If it won't be simple, it simply won't be. [Hire me, source code]


                Comment

                • Rene Pijlman
                  #5
                  Re: HTMLParser chokes on bad end tag in comment

                  Miki:[color=blue]
                  >You can also check out BeautifulSoup
                  >(http://www.crummy.com/software/BeautifulSoup/) which is less strict
                  >than the regular HTML parser.[/color]

                  Yes, thanks. Ik this case it was my sitechecker which checks for syntax
                  and broken links, so it was supposed to find the syntax error.
                  BeautifulSoup is not very well suited for validators :-)

                  --
                  René Pijlman

                    Comment

                    • Edward Elliott
                      #6
                      Re: HTMLParser chokes on bad end tag in comment

                      Fredrik Lundh wrote:
                      [color=blue][color=green]
                      >> Should it? The end tag it chokes on is in comment, isn't it?[/color]
                      >
                      > no. STYLE and SCRIPT elements contain character data, not parsed
                      > character data, so comments are treated as characters, and the first
                      > "</" ends the element.[/color]

                      Rather than take your word for it, I checked the W3C HTML4 DTD and found
                      this:

                      Performance, Implementation, and Design Notes
                      http://www.w3.org/TR/html4/appendix/notes.html#notes-specifying-data


                      Element content

                      When script or style data is the content of an element (SCRIPT and STYLE),
                      the data begins immediately after the element start tag and ends at the
                      first ETAGO ("</") delimiter followed by a name start character ([a-zA-Z]);
                      note that this may not be the element's end tag. Authors should therefore
                      escape "</" within the content. Escape mechanisms are specific to each
                      scripting or style sheet language.

                      ILLEGAL EXAMPLE:
                      The following script data incorrectly contains a "</" sequence (as part of
                      "</EM>") before the SCRIPT end tag:

                      <SCRIPT type="text/javascript">
                      document.write ("<EM>This won't work</EM>")
                      </SCRIPT>

                      In JavaScript, this code can be expressed legally by hiding the ETAGO
                      delimiter before an SGML name start character:

                      <SCRIPT type="text/javascript">
                      document.write ("<EM>This will work<\/EM>")
                      </SCRIPT>


                      Guess you learn something new every day. Too bad there's so much illegal
                      code in the wild. :(

                      --
                      Edward Elliott
                      UC Berkeley School of Law (Boalt Hall)
                      complangpython at eddeye dot net

                        Comment

                        • Fredrik Lundh
                          #7
                          Re: HTMLParser chokes on bad end tag in comment

                          Edward Elliott wrote:
                          [color=blue]
                          > Guess you learn something new every day. Too bad there's so much illegal
                          > code in the wild. :([/color]

                          if more people learned something new every day, the wild would look a
                          lot different.

                          </F>


                            Comment

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