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Re: Why is Encoding Metadata (e.g. encoding="UTF-8) put Inside

• From: David Carlisle <davidc@n...>
• To: costello@m...
• Date: Wed, 19 Sep 2007 14:10:41 +0100

One thing that your notes don't emphasise is that if the encoding is
specified in the http headers (or similar external metadata) any
encoding specified in the file must be ignored.

http://www.ietf.org/rfc/rfc3023.txt

      There are several reasons that the charset parameter is
      authoritative.  First, some MIME processing engines do transcoding
      of MIME bodies of the top-level media type "text" without
      reference to any of the internal content.  Thus, it is possible
      that some agent might change text/xml; charset="iso-2022-jp" to
      text/xml; charset="utf-8" without modifying the encoding
      declaration of an XML document.  Second, text/xml must be
      compatible with text/plain, since MIME agents that do not
      understand text/xml will fallback to handling it as text/plain.
      If the charset parameter for text/xml were not authoritative, such
      fallback would cause data corruption.


The reasons (quoted above) for this are sound in theory but a real pain
in practice where it is often easy to put the right encoding
declaration in the XML file and hard to get the right encoding specified
in the mime headers. 


David

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• References:
  • Why is Encoding Metadata (e.g. encoding="UTF-8) put Inside the XML Document?
    • From: "Costello, Roger L." <costello@m...>