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Re: Compressed JSON

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  • msf157
    I am sure this has nothing to do with the actual JSON files, but I am sending the files to the browser in gzip form and they should automagiacally decompress,
    Message 1 of 7 , Mar 7, 2006
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      I am sure this has nothing to do with the actual JSON files, but I
      am sending the files to the browser in gzip form and they should
      automagiacally decompress, before going to the parser. For some
      reason this is not hapening as it does with XML and I am unsure what
      the proper way to do this is.

      Is there a javascript command to force decompression? Are the
      normal gzip headers conflicting with the parser? Do any JSON
      parsers support gzip? Is there a better way to do this?

      -Marc

      --- In json@yahoogroups.com, henrik hjelte <henrik@...> wrote:
      >
      > On tis, 2006-03-07 at 14:43 +0000, msf157 wrote:
      > > Is it posible to compress JSON files, gzip or something else?
      Am
      > > using JSON-PHP to send JSON files to my AJAJ javascript front
      end.
      > > When I turn on GZIP compression the javascript fails to parse
      the
      > > file. I am using the open-source JS JSON parser availible from
      > > JSON.org.
      > Not that I've tried compressing JSON, or have any experience
      > with either PHP or JSON-PHP but I'm sure it's possible.
      >
      > As a fact, I will eat my hat if your problems has anything to do
      with
      > JSON.
      >
      > Is the compressed JSON uncompressed before it gets to the
      javascript
      > parser?
      > /Henrik Hjelte
      >
    • MPCM
      The communication itself should be doing the compression and undoing before it gets anywhere near the js. Is this what you are doing? Or are you sending a
      Message 2 of 7 , Mar 7, 2006
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        The communication itself should be doing the compression and undoing before
        it gets anywhere near the js.

        Is this what you are doing? Or are you sending a gzip'd output and
        expecting the browser to know how to decode it?

        --
        Matt


        [Non-text portions of this message have been removed]
      • henrik hjelte
        ... I think you have to set the proper value of the http response content-type, to a value like text/gzip or text/zip. It sort of depends on the browser if I
        Message 3 of 7 , Mar 7, 2006
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          On tis, 2006-03-07 at 16:18 +0000, msf157 wrote:
          > I am sure this has nothing to do with the actual JSON files, but I
          > am sending the files to the browser in gzip form and they should
          > automagiacally decompress, before going to the parser. For some
          > reason this is not hapening as it does with XML and I am unsure what
          > the proper way to do this is.

          I think you have to set the proper value of the http response
          content-type, to a value like text/gzip or text/zip. It sort of
          depends on the browser if I remember.

          /Henrik Hjelte
        • Tom Metro
          ... Yes, though it looks like Content-Type is unchanged, but a Content-Encoding header needs to be added. Here are a couple of articles on this that I found
          Message 4 of 7 , Mar 7, 2006
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            henrik hjelte wrote:
            >> ...I am sending the files to the browser in gzip form and they should
            >> automagiacally decompress, before going to the parser.
            >
            > I think you have to set the proper value of the http response
            > content-type, to a value like text/gzip or text/zip.

            Yes, though it looks like Content-Type is unchanged, but a
            Content-Encoding header needs to be added.

            Here are a couple of articles on this that I found when searching for
            "HTTP Compression":

            http://www.webreference.com/internet/software/servers/http/compression/

            Most newer browsers since 1998/1999 have been equipped to support the
            HTTP 1.1 standard known as "content-encoding." ... Essentially the
            browser indicates to the server that it can accept "content encoding"
            and if the server is capable it will then compress the data and
            transmit it.

            http://www.websiteoptimization.com/speed/tweak/compress/

            HTTP compression uses public domain compression algorithms, like gzip
            and compress, to compress XHTML, JavaScript, CSS, and other text files
            at the server. This standards-based method of delivering compressed
            content is built into HTTP 1.1, and most modern browsers that support
            HTTP 1.1 support ZLIB inflation of deflated documents. In other words,
            they can decompress compressed files automatically...


            So the likely problem is that your server isn't sending the correct
            Content-Encoding header. Also note that your server is supposed to be
            looking at the request headers and *only* sending compressed content if
            the client says it can handle it.

            Whether all this magic is supported by the XMLHttpRequest() API is
            another matter, but being a documented feature of HTTP 1.1 it seems
            likely that the capability is implemented in the lower layer protocol API.

            -Tom

            --
            Tom Metro
            Venture Logic, Newton, MA, USA
            "Enterprise solutions through open source."
            Professional Profile: http://tmetro.venturelogic.com/
          • msf157
            I finally got it working. The headers were being added correctly but the encoding was not. I switched methods of compression and it works perfectly. The
            Message 5 of 7 , Mar 9, 2006
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              I finally got it working. The headers were being added correctly
              but the encoding was not. I switched methods of compression and it
              works perfectly. The browser/platform should auto-decompress on the
              other end if the headers are set correctly. There should be no need
              to use a gzip library, as some suggested.

              To others that do not use compression I highly recomend it. The
              advantage of JSON is the small size, and simplicity to Parse. If
              you are not compressing your streams then you are not taking full
              advantage of the format.

              My JSON went from 5k to 1k, i know these are already small files,
              but my web interface is making dozens of calls a minute and updating
              the screen, that small decrease in size will add tons to the
              unsability of the page for those on slower connections.

              The final solution was to wrap my PHP page with start_gzip and
              end_gzip commands, the browser auto decompresses and parses the
              result wih JS.

              Thanks again to all that left feedback.

              -Marc

              --- In json@yahoogroups.com, Tom Metro <tmetro+json@...> wrote:
              >
              > henrik hjelte wrote:
              > >> ...I am sending the files to the browser in gzip form and they
              should
              > >> automagiacally decompress, before going to the parser.
              > >
              > > I think you have to set the proper value of the http response
              > > content-type, to a value like text/gzip or text/zip.
              >
              > Yes, though it looks like Content-Type is unchanged, but a
              > Content-Encoding header needs to be added.
              >
              > Here are a couple of articles on this that I found when searching
              for
              > "HTTP Compression":
              >
              >
              http://www.webreference.com/internet/software/servers/http/compressio
              n/
              >
              > Most newer browsers since 1998/1999 have been equipped to
              support the
              > HTTP 1.1 standard known as "content-encoding." ... Essentially
              the
              > browser indicates to the server that it can accept "content
              encoding"
              > and if the server is capable it will then compress the data and
              > transmit it.
              >
              > http://www.websiteoptimization.com/speed/tweak/compress/
              >
              > HTTP compression uses public domain compression algorithms,
              like gzip
              > and compress, to compress XHTML, JavaScript, CSS, and other
              text files
              > at the server. This standards-based method of delivering
              compressed
              > content is built into HTTP 1.1, and most modern browsers that
              support
              > HTTP 1.1 support ZLIB inflation of deflated documents. In other
              words,
              > they can decompress compressed files automatically...
              >
              >
              > So the likely problem is that your server isn't sending the
              correct
              > Content-Encoding header. Also note that your server is supposed to
              be
              > looking at the request headers and *only* sending compressed
              content if
              > the client says it can handle it.
              >
              > Whether all this magic is supported by the XMLHttpRequest() API is
              > another matter, but being a documented feature of HTTP 1.1 it
              seems
              > likely that the capability is implemented in the lower layer
              protocol API.
              >
              > -Tom
              >
              > --
              > Tom Metro
              > Venture Logic, Newton, MA, USA
              > "Enterprise solutions through open source."
              > Professional Profile: http://tmetro.venturelogic.com/
              >
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