Re: [mapserver-users] Designing a wrapper around mapserv which can be used with fcgi

[Andy Colson]

Adrian Popa wrote:
Hello everyone,
I am currently using a wrapper around mapserv which receives the URL 
parameters, builds the map file (actually I only need to set some 
filters in the map file, but the filters need to be built after running 
some SQL queries with the passed in parameters). After the map file is 
built, mapserv is called (as a shell script), and the map gets sent to 
the user. Currently this wrapper is written in perl - so it's not 
terribly fast as a cgi process.

While this approach works, it is terribly inefficient. I would like to 
use mapserv as a fcgi process (or something faster than plain cgi). My 
question is - how can I /should I build a wrapper around mapserv that 
can "customize" the MAP file on the fly and run as a fcgi process?

Any ideas on where I should start? An example of such a wrapper?

Also, I suspect I can send parameters to mapserver and use some sort of 
variables in the map file to set up my filters - but I haven't seen an 
example. Can someone point me to such a documentation?

Thanks,
Adrian

Have you seen mapscript?  You can use mapserver directly from perl.  And 
perl can do fast-cgi.  Here is a little, ad-hoc, non-tested, perl fcgi:


#!/usr/bin/perl

use strict;
use mapscript;
use FCGI;


my $request = FCGI::Request( );
while($request->Accept() >= 0)
{
        my($req, $x, $at, $xmap, $xpin, $sid, $y, $q);

        $req = new mapscript::OWSRequest();
        $req->loadParams();

        $xmap = $req->getValueByName('map');
        $xpin = $req->getValueByName('pin');

        my $map = new mapscript::mapObj( "/maps/$xmap.map" );
        if (! $map)
        {
                #print STDERR "----- Error loading map: $xmap.map\n";
                print("Content-type: text/text\r\n\r\n");
                print "cant load $xmap.map";
                $request->Finish();
                next;
        }

        mapscript::msIO_installStdoutToBuffer();

        $x = $map->OWSDispatch( $req );
        if ($x)
        {
                print STDERR "OWSDispatch: $x\n";
                my $errObj = new mapscript::errorObj();
                while ($errObj) {
                        print STDERR "ERROR: 
$errObj->{code}:$errObj->{message}:$errObj->{routine} \n";
                        $errObj = $errObj->next();
                }
        }

        my $content_type = mapscript::msIO_stripStdoutBufferContentType();

        $x = mapscript::msIO_getStdoutBufferBytes();


        print("Content-type: $content_type\r\n\r\n");
        if (mapscript::msGetVersionInt() >= 50500)
        {
                print $$x;
        } else {
                print $x;
        }

        mapscript::msIO_resetHandlers();
        $request->Finish();
}



I'd recommend using mapserver 5.6.0.

-Andy
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