[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