calling Perl script from javascript

Discussion in 'Javascript' started by Richard Trahan, Aug 8, 2004.

  1. I want a js function to call a Perl script residing on a server.
    The Perl script will return a string, to be used by the js.
    Pseudo code:
    <script>
    stringvar = perlfunc_on_server(stringarg)
    document.write(stringvar)
    </script>

    Can stringvar above be a url?

    The perlfunc_on_server could take the form of a GET,
    like www.myserver.com/cgi-bin/perlfunc_on_server.pl?arg=stringarg

    Any other kludge is okay, as long as it works.

    I'm very experienced with Perl, but a newbie to js.
    Source code would help. Thanks.
     
    Richard Trahan, Aug 8, 2004
    #1
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  2. Richard Trahan

    Erwin Moller Guest

    Richard Trahan wrote:

    > I want a js function to call a Perl script residing on a server.
    > The Perl script will return a string, to be used by the js.
    > Pseudo code:
    > <script>
    > stringvar = perlfunc_on_server(stringarg)
    > document.write(stringvar)
    > </script>
    >
    > Can stringvar above be a url?
    >
    > The perlfunc_on_server could take the form of a GET,
    > like www.myserver.com/cgi-bin/perlfunc_on_server.pl?arg=stringarg
    >
    > Any other kludge is okay, as long as it works.
    >
    > I'm very experienced with Perl, but a newbie to js.
    > Source code would help. Thanks.


    Hi,

    If you need JS to get some interaction with a SERVERSIDE script, you have
    to:
    1) call that script
    2) receive the response and do something usefull with it.

    the easiest way is to use a hidden frame (or a new window, as long as you
    have a window) in which you replace the URL with your call to the
    Perlscript.
    The Perlscript has to respond in a way that can be used in javascript.
    In such situations I always let the server respond with a normal HTML-page
    that has an onLoad-handler that call some javascript-function.
    That function contains serverside information you need.

    Eg (php example because my Perl sucks)

    <html>
    <head>
    <script type="text/javascript">
    function passInfo(){
    alert("I received: <?= $_GET["userid"] ?>");
    }
    </script>
    </head>
    <body onLoad="passInfo();">
    Leave this empty, not needed.
    </body>
    </html>

    if you call the above page in some hidden frame it will respond with an
    alert saying 'I received: 23':
    example.php?userid=23

    The $_GET example is lame of course, but you can just do all your serverside
    Perlstuff over there.
    Instead of the alert you can call some JS-function in your main-page,
    possibly passing the needed info from the server.

    Stuff you need to know to do this is:
    1) how you make (hidden) frames. (frame and frameset)
    2) replace the content of a window
    top.frames["framename"].location = .......
    3) how to make calls to a JS-function in another window.
    top.frames["someFrameName"].someFunction(1,2,3);

    Hope that helps.
    Good luck,
    Erwin Moller
     
    Erwin Moller, Aug 8, 2004
    #2
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  3. Richard Trahan wrote:

    > I want a js function to call a Perl script residing on a server.
    > The Perl script will return a string, to be used by the js.
    > Pseudo code:
    > <script>
    > stringvar = perlfunc_on_server(stringarg)
    > document.write(stringvar)
    > </script>


    Well if you want to receive some text from the Perl script and display
    it directly (document.write does that) I am not sure why you need
    JavaScript at all, you could solve that on the server and use Perl to
    read the text from the (other?) server and then include that in your
    page with Perl.


    > Can stringvar above be a url?


    What you can do with HTML is
    <script type="text/javascript"
    src="www.myserver.com/cgi-bin/perlfunc_on_server.pl?arg=stringarg"></script>
    that way you simply need to make sure your perlfunc_on_server.pl sets
    the Content-Type to application/x-javascript and sends syntactically
    correct JavaScript back.

    > The perlfunc_on_server could take the form of a GET,
    > like www.myserver.com/cgi-bin/perlfunc_on_server.pl?arg=stringarg
    >
    > Any other kludge is okay, as long as it works.
    >
    > I'm very experienced with Perl, but a newbie to js.
    > Source code would help.


    The biggest problem could be the same origin policy governing
    client-side scripting so while in theory in new browsers like Mozilla,
    IE5+/Win, Safari you can make HTTP requests and receive the result you
    can usually only connect back to the server the HTML page with the
    script comes from.
    See
    http://www.faqts.com/knowledge_base/view.phtml/aid/17226/fid/616
    http://jibbering.com/2002/4/httprequest.html

    There are also solutions using an iframe (usually a hidden one) to
    perform the request to the server and returning some script that updates
    the document containing the iframe but in this case too you are
    restricted by the same origin policy.


    --

    Martin Honnen
    http://JavaScript.FAQTs.com/
     
    Martin Honnen, Aug 8, 2004
    #3
  4. Thank you for your detailed reply.

    Although a great idea, I cannot create an invisible frame
    because the client window is an eBay ad. eBay software will
    detect the frame creation code and delete the ad, as they
    explicitly prohibit frames.

    Is it true in general that js functions which take a string
    argument will also take a url? I.e., can I do something like
    alert(url(http://myserver.com)) ?
     
    Richard Trahan, Aug 8, 2004
    #4
  5. Richard Trahan

    Andre Herbst Guest

    Richard Trahan wrote:

    > Is it true in general that js functions which take a string
    > argument will also take a url? I.e., can I do something like
    > alert(url(http://myserver.com)) ?


    This is partly true. Because an URL is also a string. You could call the
    function:

    alert("http://myserver.com")
     
    Andre Herbst, Aug 8, 2004
    #5
  6. Martin Honnen wrote:

    Thank you for responding.

    > What you can do with HTML is
    > <script type="text/javascript"
    > src="www.myserver.com/cgi-bin/perlfunc_on_server.pl?arg=stringarg"></script>
    >
    > that way you simply need to make sure your perlfunc_on_server.pl sets
    > the Content-Type to application/x-javascript and sends syntactically
    > correct JavaScript back.


    That's exactly what I'm looking for. Thank you so much. I have not
    been able to find a decent textbook or tutorial that explains exactly
    how the various MIMEs are used in CGI programming.
    The texts on network programming are all obsessed with
    sockets, not CGI. Do you know of a good book?
     
    Richard Trahan, Aug 8, 2004
    #6
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