MS RFC 8: Pluggable External Feature Layer Providers

[Sean Gillies]

On Oct 27, 2005, at 5:47 AM, Daniel Morissette wrote:

> Jani Averbach wrote:
>
>>
>> I would like to ask MS TSC to vote for this proposal. I am sorry  
>> that this
>> came so late, but if this passes, it will be ready and implemented  
>> for coming 4.8
>> before feature freeze.
>>
>>
>
> You realize that Oct 31st is only 4 days away?
>
>
>> The proposal is important because it actually implements the way  
>> to include external
>> providers for Mapserver.  As technically, it isn't very big  
>> because mostly all work
>> has been done by MS-RFC-3 (vtable architecture).
>>
>> http://ms.gis.umn.edu/development/rfc/ms-rfc-8
>>
>>
>
> In the proposal you wrote:
>
>
>> Technical Solution
>>
>>     * New MAP-file keyword PLUGINLIB with string argument. This  
>> keywords tells which library dynamically to load for this layer.
>>     * New connection type CUSTOM
>>
>>
>
> So this means that the PLUGINLIB parameter needs to be set explicitly
> for each layer that uses a given plugin? Is the value the full path  
> to a
> .so file (DLL on Windows)? e.g.
> PLUGINLIB  "/opt/mapserver/plugins/myplugin.so"
>
> This could make it painful to migrate mapfiles from windows to Linux
> because then you need to edit every single layer to change the path  
> and
> extension.
>
> How about a more automated mechanism where we set a MS_PLUGIN_DIR
> variable in the environment prior to calling MapServer or via a CONFIG
> directive at the map level, then the PLUGINLIB becomes a PLUGIN  
> keyword
> whose value is the basename of the plugin file?
>
> e.g. the example above becomes:
>
> MAP
>    ...
>    CONFIG "MS_PLUGIN_DIR" "/opt/mapserver/plugins"
>    ...
>
>    LAYER
>      CONNECTIONTYPE CUSTOM
>      PLUGIN "myplugin"
>      ...
>     END
> END
>
>
> Daniel
> -- 
> ------------------------------------------------------------
>   Daniel Morissette               dmorissette at dmsolutions.ca
>   DM Solutions Group              http://www.dmsolutions.ca/
> ------------------------------------------------------------
>


Daniel,

I want to be able to use absolute paths instead of a combination of  
relative path and environment variable or config property, and I  
think others will also want this option.

Jani,


What would you think about a change from CONNECTIONTYPE CUSTOM ->  
CONNECTIONTYPE PLUGIN? I think that the meaning of "PLUGIN" will be  
more clear to users.

Sean

---
Sean Gillies
sgillies at frii.com
http://zcologia.com