[mapserver-users] ASP Implementation Notes (re-post from 10/23)

Thu Dec 6 11:50:32 PST 2001

Rich -

Yes, I use ASPExec (the ServerObjects tool) as well.  The chief
limitation of that approach is that you must be executing the
application on the same machine as the IIS Web server that's running the
ASP page.  In my case, the MapServer system is usually NOT on the local
machine, and is better suited for the HTTP interface.

	- Ed

Ed McNierney
Chief Mapmaker
TopoZone.com
ed at topozone.com
(978) 251-4242

-----Original Message-----
From: Richard Greenwood [mailto:Rich at GreenwoodMap.com]
Sent: Thursday, December 06, 2001 1:30 PM
To: Ed McNierney
Cc: mapserver-users at lists.gis.umn.edu
Subject: RE: [mapserver-users] ASP Implementation Notes (re-post from
10/23)

Ed,

Thanks for sharing you ASP knowledge and for providing such a detailed 
example. Another way to do pretty much the same thing is:
     mapserver.exe QUERY_STRING=xxxxxxxxxxxx
This allows you to run mapserver from the command prompt without calling
it 
from a httpd, although I don't know if it is considered a supported 
interface (Steve?). Basic ASP doesn't let you execute external commands
but 
www.serverobjects.com has a free tool that provides that ability.

Another very general comment on using ASP and MapServer together -
there's 
nothing wrong with mixing ASP and CGI pages on the same site. e.g. I
have a 
series of reports that are generated by user queries against a SQL
Server 
database and displayed in ASP pages. The user can click a line in the 
report which calls MapServer with appropriate parameters to map the
record 
the user clicked.

Rich

At 08:57 AM 12/6/2001 -0500, you wrote:
>Folks -
>
>The current thread about ASP implementation issues with MapServer
>prompts me to provide a few ideas for folks struggling in that
>direction.
>
>One of the great benefits of MapServer is its ability to provide a LOT
>of power and capability to users who are NOT using a scripting
>environment such as PHP or ASP or whatever.  The ability to echo state
>information into form variables gives you lots of flexibility.
>
>On the other hand, if you ARE using a scripting environment, this
>capability will get in your way.  You don't hear problems from people
>using PHP asking how to make MapServer generate PHP output.  Why?
>Because they don't think of the problem that way.  They use MapScript
to
>control the operation of MapServer externally (not the mapserv binary
>exactly, but you get the point).
>
>There are some pretty simple things you can do to make life easier in
>the ASP environment.  It would be great to have an ASP-style MapScript
>someday, but there's a lot you can do right now.
>
>First, make sure your ASP environment is "on top".  That is, you're
>going to use an ASP page to direct MapServer, not use MapServer to
>generate ASP.
>
>Second, don't use MapServer to do things you can do yourself in ASP.  A
>lot of what MapServer does with template files is help to preserve
state
>information.  An HTML form can be pre-filled with lots of settings that
>simply reflect the current mapping state, so it's easy to let the user
>make a few modifications and make a new map (i.e. resubmit the form).
>But you don't need that in an ASP environment!  You can remember what
>your parameters were, no?
>
>Here's a very simple example that might help ASP developers think
>differently (with apologies to Apple).  Let's start with getting a
layer
>name from my ASP parameters.  The URL being processed here is:
>
>http://myserver.com/iwanttouse.asp?mybaselayer=BASEMAP
>
>Here's how to start:
>
><%
>         layername = Request.QueryString ("mybaselayer")
>%>
>
>I can pull off any other useful parameters from my ASP querystring that
>I like.  They don't have to be MapServer parameters - I just get enough
>info to describe the map I want in any format that's convenient and
>appropriate for the application.  I can then generate the MapServer
>querystring myself.
>
>Although there are several ways to do the next step, I then use a nice
>little component called ASPHTTP (www.serverobjects.com) that lets you
>submit HTTP requests and get the results back in a string variable.  So
>to submit a request to MapServer and get the results back in a VBScript
>string, you can do this:
>
><%
>'
>'       mapServerURL has been set to the complete MapServer
querystring,
>adding the
>'       layername I extracted from the ASP page parameters:
>'
>         mapServerURL =
>"http://myserver.com/cgi-bin/mapserv.exe?map=mymapfile.map&layer=" &
>layername
>'
>'       Issue that HTTP GET request and retrieve the HTML MapServer
>returns into a string variable
>'
>         Set httpObj = Server.CreateObject("AspHTTP.Conn")       '
Create
>the object
>         HTTPObj.Url = mapServerURL
>' Set the URL
>         mapServerHTML = HTTPObj.GetURL                          '
Issue
>HTTP GET and store output in mapServerHTML
>         Set httpObj = Nothing
>%>
>
>Now the string mapServerHTML has the complete HTML generated by
>MapServer from your TEMPLATE file.  That's nice, you say, but what do I
>do with that big HTML file now?  You do very little, because you don't
>have a big HTML file.  Your HTML file, generated by MapServer, and now
>resident inside the string mapServerHTML, looks like this:
>
><!-- MapServer header line -->
>/tmp/Map123.jpg|/tmp/MapSB123.jpg
>
>What's that?  It's the output you get when your TEMPLATE file looks
like
>this:
>
>[img]|[scalebar]
>
>That's all.  You don't need to make MapServer generate a whole HTML
page
>for you - you've got your ASP page to do that.  Once you get MapServer
>to generate this little HTML tidbit for you, parse it out into two ASP
>string variables, one with the URL of the map image file, one with the
>URL of the scalebar image file (note the lack of error checking):
>
><%
>         commentPos = InStr (mapServerHTML, ">")         ' Strip out
>MapServer header comment
>         delimiterPos = InStr (mapServerHTML, "|")               ' Find
>field separator
>         imgURL = Mid (mapServerHTML, commentPos + 1, delimiterPos -
>commentPos - 1)
>         scalebarURL = Mid (mapServerHTML, delimiterPos + 1)
>%>
>
>Now I'm ready to generate my output HTML page.  I've taken my ASP
>parameters, generated a MapServer request, directed MapServer to
>generate the map image and a scalebar image, and I've put the URLs of
>those images into the variables imgURL and scalebarURL.
>
>The rest of my ASP page will generate my HTML (all the stuff that's NOT
>in the TEMPLATE file).  At strategic points I will do things like:
>
><table>
>   <tr>
>     <td>
>       <img src="<% =imgURL %>"><br>
>       <img src="<% =scalebarURL %>">
>     </td>
>   </tr>
></table>
>
>or other such thing.  I get to develop my pages in ASP and make
>MapServer do all the work!
>
>         - Ed
>
>Ed McNierney
>Chief Mapmaker
>TopoZone.com
>ed at topozone.com
>(978) 251-4242
>
>
>-----Original Message-----
>From: Jan Hartmann [mailto:jhart at frw.uva.nl]
>Sent: Thursday, December 06, 2001 8:52 AM
>To: Ed McNierney; mapserver-users at lists.gis.umn.edu
>Subject: RE: [mapserver-users] MapServer, ArcIMS, or SVG??
>
>
>At 09:57 AM 12/5/2001 -0500, Ed McNiemey wrote:
>
>
> >Can MapServer be used with Java or ASP?  Yes.  I have developed an
> >application for a customer that uses a lot of both.  I also posted a
> >note on the list a while ago about some techniques for using
MapServer
> >effectively in an ASP environment.
>
>
>I searched the mailing list on ASP and Active Server Pages, but found
>nothing but the entries for the last few days. Could you give some
>details
>on using MapServer with ASP?
>
>Jan Hartmann
>Department of Geography
>University of Amsterdam
>jhart at frw.uva.nl

Richard W. Greenwood, PLS
Greenwood Mapping, Inc.
Rich at GreenwoodMap.com
(307) 733-0203
http://www.GreenwoodMap.com