[mapguide-internals] Session-MapName-Map

[Paul Spencer]

Haris,

I'm not sure if I really know what I am talking about here, but my  
understanding is that when you start up a session with a  
MapDefinition, you can save the runtime MgMap object to the session  
repository as a Map resource and give it a name at that time.  The  
name is arbitrary, but in the case of the AJAX viewer it is  
predictable from the MapDefinition name and I think you are right  
that it would either blow away the existing Map or conflict in some way.

I'm not sure how the existing viewer works, but it doesn't contain  
the capability to change maps at run time so it would never run into  
this issue.  In Fusion, we can load different MapDefinitions at run  
time and we do something like this when the user wants to load the map:
/* $mapid is a string resource id Library://... */
$resourceID = new  MgResourceIdentifier($mapid);
$map = new MgMap();
$mapName = $resourceID->GetName();
$map->Create($resourceService, $resourceID, $mapName);
$mapStateId = new MgResourceIdentifier("Session:" . $sessionID .  
"//" . $map->GetName() . "." . MgResourceType::Map);
$map->Save($resourceService, $mapStateId);

(NB: there is a potential problem here if the map name is the same as  
one already in the session.  I will need to fix this potential bug in  
Fusion - I will probably use an md5 hash of the string version of the  
full Library:// path to the original map.  This would probably look  
like:

$mapName = md5($mapid);

and the rest of the code would look the same.
)

We return the $mapName to the client so that subsequent requests can  
operate on the the appropriate Map object on the server side using  
something like this:

$map = new MgMap();
$map->Open($resourceService, $mapName);

The mapagent rendering operations take the session id and the map  
name to render map images and dynamic map overlays.

Does that help?

Cheers

Paul

On 31-Aug-07, at 1:05 PM, Haris Kurtagic wrote:

> I would appreciate if someone could help me to clarify
> Session-MapName-Map interaction.
>
>
>
> Now how MG Viewer-Server  is working is that it will create new  
> session
> and read web layout and create a runtime map in session repository.
>
> Later runtime map is accessed by name (only name part of it) from the
> session repository.
>
> So, if I would have two Maps created in Library in separate folders  
> with
> same name and if I would add the second map to session repository I
> could not access both Maps ( because Session Id and MapName are  
> used to
> identify it - and they are same).
>
>
>
> Am I right about this ?
>
>
>
> Thanks,
>
> Haris
>
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> mapguide-internals mailing list
> mapguide-internals at lists.osgeo.org
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+-----------------------------------------------------------------+
|Paul Spencer                          pspencer at dmsolutions.ca    |
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|Chief Technology Officer                                         |
|DM Solutions Group Inc                http://www.dmsolutions.ca/ |
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