[mapserver-users] Re: Feature wish: Internal mapfile variables

[Bob Basques]

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> 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
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>
>
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