[mapserver-users] Re: Feature wish: Internal mapfile variables
Stephen Woodbridge
woodbri at swoodbridge.com
Mon Oct 3 19:16:53 EDT 2011
In Theory, you could do this today by writing a simple wrapper script
that reads the CGI arguments, calls a script and passes it the output
file name like /tmp/mapwrap-$$.map and the arguments. The script would
read the template mapfile passed in the arguments do the substitution
and write out the new mapfile. Then it would call mapserv and pass the
appropriate arguments including the new mapfile. and after mapserv runs
it can remove the tmp mapfile.
The downside of this is that it requires at least three process creates
instead of one. And you have to be aware of the security issues of doing
this and worry about SQL injection, information leakage, etc.
The upside is that you could do it now in say Perl, PHP, Python today if
you wanted to prototype up something and play with the idea. Pick the
language you like best and go for it.
-Steve W
On 10/3/2011 6:22 PM, Matt McClelland wrote:
> I am new to mapserver world, so as you read this, remember I have no
> idea what I am talking about :)
>
> I was thinking about this problem last week, my idea was to look at
> passing a reference to a parsing script, that outputs a mapfile.
>
> so instead of this
> http://localhost/cgi-bin/mapserv?client_id=123&mode=map&map=/path/to/mapfile.map&.
> <http://localhost/cgi-bin/mapserv?client_id=123&mode=map&map=/path/to/mapfile.map&.>..
> you would pass this url
> http://localhost/cgi-bin/mapserv?client_id=123&mode=map&map=/path/to/mapfilescript&.
> <http://localhost/cgi-bin/mapserv?client_id=123&mode=map&map=/path/to/mapfile.map&.>..
>
> So the only change to mapserver would be to kindly ask it to pass
> variables when getting a mapfile. eg
> /path/to/mapfilescript&client_id=123&mode=map&bbox=........ etc
>
> Then the custom parsing script could do lots of things, like search and
> replace $client_id with "123" or include other files etc. It could
> also build an entire mapfile from scratch, pull stuff from a DB, cache
> common requests and I guess lots more.
>
> As I said I have no idea if this is plausible, or if it would impact on
> speed to much etc
>
> Matt :)
>
>
> On Tue, Oct 4, 2011 at 8:10 AM, Bob Basques <Bob.Basques at ci.stpaul.mn.us
> <mailto:Bob.Basques at ci.stpaul.mn.us>> wrote:
>
> All,
>
>
> I did submit a request very similar to the idea of passing in a
> MAPFILE as a mapserv parameter a few years back. As I recall there
> was some discussion about the idea, and there were also the same
> sorts of reservations about it then, especially the KISS part. In
> very early uses of MapServer, we used our own wrapper around it to
> provide this type of functionality, but it ended up too cumbersome
> to maintain along with different versions of MapServ as they came
> along, so we let the idea go. It really needs to be passed through
> MapServer to be a viable option IMO. Otherwise you need to support
> to many pieces of things to make things very portable.
>
>
> I thought the recent introduction of the browse mode using a
> OpenLayers template might resurrect the idea to some degree, but
> that didn't happen either. I suggested a template passing mechanism
> for that for example, why restrict to just Openlayers, got some
> discussion going on it, but that was all.
>
>
> I think it will come about at some point, certainly more folks
> wanting it now than when I first started asking the question :c) .
>
>
> bobb
>
>
>
>
> >>> Stephen Woodbridge <woodbri at swoodbridge.com
> <mailto:woodbri at swoodbridge.com>> wrote:
>
> Robert,
>
> All good questions!
>
> Here are some thoughts on this.
>
> 1. we all ready have the CGI parameter substitution, but it does require
> reading the mapfile to get its validation parameters.
>
> 2. we already support includes
>
> 3. you would have to read some of the mapfile to get the connection
> parameters to access the parameters from a database
>
> 4. I like the idea of getting the mapfile from the database, but I think
> if I were to go that route, why would I not keep the whole map file in
> the database? it would be easy to store it as fragments and parameters
> and do the substitution all in the database and just return a text blob
> as a mapfile for mapserver to parse. In Postgresql it would be easy to
> write a few stored procedures to help manage this and implement it on
> the database side of things.
>
> 5. Follow the KISS principal. Keep is simple, make the approach
> incremental based on the existing code as much as possible
>
> -Steve W
>
> On 10/3/2011 3:59 PM, reholl wrote:
> > I really like the idea of pulling mapfile resources from RDBMS
> and URL.
> > For the URL, I don't think the communications part poses much of a
> > challenge, as the cURL stuff used in the OWS client can be
> repackaged. I
> > did that once to make a mapserv CONNECTIONTYPE as a SOAP client.
> I can
> > certainly picture a somewhat generalized mechanism: "fill ANY mapfile
> > value from some outside resource that delivers a construct of the
> proper
> > form/type." These resources might be chained or arranged in branches.
> > (Does this begin to stray into WPS territory..?) Anything of this
> > complexity poses a risk to performance and readability. There's
> > definitely something to be said for the everything-is-right-here
> aspect
> > of the mapfile. Does mapserv configuration becomes less 'file'
> and more
> > 'system.' and with what new maintenance headaches? Or another way to
> > view it: mapfile syntax becomes a de facto programming language,
> and we
> > already have mapscript in numerous flavors. What's the tipping
> point for
> > "let's move this complexity into core mapserver"? Given all these
> > caveats, I'd love to explore this further... Robert Hollingsworth
> >
> > blammo wrote:
> > All, Would adding in INCLUDEs from a URL be pushing it too
> much, as
> > in: INCLUDE "http://Myserver.com/cgi-bin/myscript.pl" Could
> pass in
> > parameters like so . . . INCLUDE
> > "http://Myserver.com/cgi-bin/myscript.pl?A=first thing&b=second
> > thing&c=third thing . . ." bobb >>> "Smith, Michael
> ERDC-CRREL-NH"
> > <[hidden email] </user/SendEmail.jtp?type=node&node=6856380&i=0>>
> > wrote: There is an RFC to have includes come from non-file
> > connections (databases). It would be another option
> > http://mapserver.org/development/rfc/ms-rfc-74.html Mike -- Michael
> > Smith Remote Sensing/GIS Center US Army Corps of Engineers On
> > 10/3/11 2:51 PM, "Stephen Woodbridge" <[hidden email]
> > </user/SendEmail.jtp?type=node&node=6856380&i=1>> wrote: >One idea
> > regarding this that you might want to consider is the ability >to
> > put all the named parameters in an include file, then be able to
> > >include that file via a CGI parameter. So it might look like this:
> > > >
> >
> >
> > View this message in context: Re: Feature wish: Internal mapfile
> > variables
> >
> <http://osgeo-org.1803224.n2.nabble.com/Feature-wish-Internal-mapfile-variables-tp6853853p6856380.html>
> > Sent from the Mapserver - User mailing list archive
> >
> <http://osgeo-org.1803224.n2.nabble.com/Mapserver-User-f1969211.html> at
> > Nabble.com.
> >
> >
> > _______________________________________________
> > mapserver-users mailing list
> > mapserver-users at lists.osgeo.org
> <mailto:mapserver-users at lists.osgeo.org>
> > http://lists.osgeo.org/mailman/listinfo/mapserver-users
>
> _______________________________________________
> mapserver-users mailing list
> mapserver-users at lists.osgeo.org <mailto:mapserver-users at lists.osgeo.org>
> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>
>
> _______________________________________________
> mapserver-users mailing list
> mapserver-users at lists.osgeo.org <mailto:mapserver-users at lists.osgeo.org>
> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>
>
>
>
> _______________________________________________
> mapserver-users mailing list
> mapserver-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/mapserver-users
More information about the mapserver-users
mailing list