Generated file

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  • Andrew Clark
    #1

    Generated file

    Hello,

    I am 99% sure that the problem I am having is not PHP related, but to
    remove my doubt, I am posting here.

    I have a search page (interfacing with MySql) that displays results in an
    IFRAME on the search page. I did this so the whole page would not have to
    be reloaded on each query.

    Each time I query the DB, I write the result set to a file and include this
    file as javascript source on the results page. Up to this point everything
    works fine, which is why I say I don't think this is PHP related.

    I use javascript to "walk" the recordset. In internet explorer (only), the
    first query recordset is all that is ever seen by the search page, even
    though the javascript source file is correctly generated. Maybe this is a
    little opaque so I will give an example.

    search.html
    --
    <IFRAME NAME="dataifram e" SRC="blank.html "></IFRAME>
    [...]
    <FORM ACTION="display .php" METHOD="post" TARGET="dataifr ame">
    <INPUT TYPE="submit">
    </FORM>

    display.php
    --
    session_start ();
    $filename = "tmp/" . session_id () . ".js";

    // write recordset...
    // include here
    echo "<SCRIPT TYPE=\"text/javascript\" SRC=\"$filename \">

    --
    This file is always generated correctly. The problem arises when the
    browser (IE) does not use the updated values in $filename. It is my belief
    that IE caches the values in this file and when the frame is reloaded, IE
    tries to be "smart" and sees that I am including the same file, and
    therefore does not reload from the file but from its cache.

    Now that I think about it, since the file is being correctly generated,
    this is 100% NOT PHP related. Could someone shed light on this anyway? It
    would be much appreciated.

    Thanks,
    Andrew
    Tags: None
    • Alvaro G. Vicario
      #2
      Re: Generated file

      *** Andrew Clark escribió/wrote (Sun, 27 Nov 2005 18:36:37 +0000):[color=blue]
      > It is my belief
      > that IE caches the values in this file and when the frame is reloaded, IE
      > tries to be "smart" and sees that I am including the same file, and
      > therefore does not reload from the file but from its cache.[/color]

      I don't whether IE obeys date headers but you can tag the script document so it expires inmediately:

      header('Last-Modified: ' . gmdate('D, d M Y H:i:s', time()-86400*365*10) . ' GMT');
      header('Expires : ' . gmdate('D, d M Y H:i:s', time()-86400*365*10) . ' GMT');


      // HTTP/1.1
      header('Cache-Control: no-store, no-cache, must-revalidate');
      header('Cache-Control: post-check=0, pre-check=0', FALSE);

      // HTTP/1.0
      header('Pragma: no-cache');


      BTW, have you remembered to set the appropriate Content-Type header?

      --
      -+ Álvaro G. Vicario - Burgos, Spain
      ++ http://bits.demogracia.com es mi sitio para programadores web
      +- http://www.demogracia.com es mi web de humor libre de cloro
      --

        Comment

        • Csaba Gabor
          #3
          Re: Generated file

          Besides the comments of Alvaro on cacheing, you can see some additional
          comments at http://php.net/imagecreatefrompng.

          Another technique some people use (which I don't recommend for
          production, but may be OK for testing) is to append a dummy query
          string to the end of the main page with a random component: "?rubbish="
          + randomNumber(). This ensures that the page is not cached.

          Csaba Gabor from Vienna

          Andrew Clark wrote:[color=blue]
          > Hello,
          >
          > I am 99% sure that the problem I am having is not PHP related, but to
          > remove my doubt, I am posting here.
          >
          > I have a search page (interfacing with MySql) that displays results in an
          > IFRAME on the search page. I did this so the whole page would not have to
          > be reloaded on each query.
          >
          > Each time I query the DB, I write the result set to a file and include this
          > file as javascript source on the results page. Up to this point everything
          > works fine, which is why I say I don't think this is PHP related.
          >
          > I use javascript to "walk" the recordset. In internet explorer (only), the
          > first query recordset is all that is ever seen by the search page, even
          > though the javascript source file is correctly generated. Maybe this is a
          > little opaque so I will give an example.
          >
          > search.html
          > --
          > <IFRAME NAME="dataifram e" SRC="blank.html "></IFRAME>
          > [...]
          > <FORM ACTION="display .php" METHOD="post" TARGET="dataifr ame">
          > <INPUT TYPE="submit">
          > </FORM>
          >
          > display.php
          > --
          > session_start ();
          > $filename = "tmp/" . session_id () . ".js";
          >
          > // write recordset...
          > // include here
          > echo "<SCRIPT TYPE=\"text/javascript\" SRC=\"$filename \">
          >
          > --
          > This file is always generated correctly. The problem arises when the
          > browser (IE) does not use the updated values in $filename. It is my belief
          > that IE caches the values in this file and when the frame is reloaded, IE
          > tries to be "smart" and sees that I am including the same file, and
          > therefore does not reload from the file but from its cache.
          >
          > Now that I think about it, since the file is being correctly generated,
          > this is 100% NOT PHP related. Could someone shed light on this anyway? It
          > would be much appreciated.
          >
          > Thanks,
          > Andrew[/color]

            Comment

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