[mapserver-users] How to use Perl with Mapscript (was Re: The right tool for the job)

[Brent Fraser]

Colin,

> Other than those pages, I couldn't find much that would
really help me
> learn about MapScript and Perl.  Maybe I'll just follow
along with the
> PHP example at the following URL and hope the API is
similar.  It looks
> like the Perl MapScript module follows MapScript's C API;
perhaps the
> PHP module does, too?

I'm not a Mapscript user but I believe that is true.
Mapscript comes with serveral language bindings (including
Perl) and they are all automatically generated , so I would
expect they are the same (allowing for language
differences).

> Is there a MapScript API reference buried somewhere that I
could read?
> And, also, a map file API reference?  I'm really quite
lost when it
> comes to map files.

On the New Users page there are links to the MapScript API
(Section 2).  the map file reference is under the
"Documentation" -> references link, but it's tough to build
a working map file from scratch using just the doc.

I would HIGHLY RECOMMEND the advice in Section 5.2 Get the
Demo Running.  Looking at (and tweaking) the map file in the
demo will be  a big help in understanding what can be done.

> >   Make sure you read the New User page:
> > http://mapserver.gis.umn.edu/new_users.

>
> I would like my first step to be putting a static image on
a web site.
> The image would be generated by Perl and returned to the
browser as a
> simple image/png.
>
> The method I have in mind follows.
>
> Each user has a set of airports and routes with which they
are
> concerned.  This set of airports and routes could change
as frequently
> as every 30 seconds.  So, for each map generation request,
I would
> dynamically create a map file and store it as TEXT in my
PostgreSQL
> database, along with some unique ID.  Then, I would output
an <img />
> tag to the browser that includes the unique ID of this
> dynamically-generated map file:
>
> <img src="/foo/mapImage.pl?id=1234" />
>
> mapImage.pl sees id=1234, pulls map file 1234 out of the
database, uses
> the MapServer back-end to generate a map, then outputs
this map as an
> image/png.  I think mapImage.pl ends up being pretty
simple: create a
> mapserver object, pipe the map file text to it, and get
the png it
> generates.  Is that it, or am I thinking too narrowly
here?
>

Depends.  You could just use Perl+Mapscript to general the
png file then and there.  I think if you use MapScript there
is no requirement to have map file; all the elements a
supplied by making function calls in Perl to mapscript then
asking for the graphic to be generated (but the scripting
users would know more about that).

Brent