[OpenLayers-Users] Idea/request for extending permalink and argparser

[Christopher Schmidt]

On Fri, Nov 21, 2008 at 11:36:59AM -0500, Stephen Woodbridge wrote:
> I have an idea that might be a useful extension to the Permalink control 
> that would allow it to support arbitrary additional parameters. It would 
> involve adding a callback to the control creation and adding an 
> additional method(s) for setting the additional argument values.
> 
> Usage would be something like this:
> 
>      var plink = new OpenLayers.Control.Permalink(
>           "permalink", base, {}, mycallback);
> 
>      map.addControl(plink);

The third argument of controls is an options hash. All options hashes in
OpenLayers extend the default/base object properties and methods -- any
'key' in the option hash will override the corresponding key on the
class you're using. 

With the existing code, this means that you can do the following:

 * Create a new myCreateArgs function:

function myCreateArgs() {
    var args = 
        OpenLayers.Control.Permalink.prototype.createParams.apply(
            this, arguments
        );
    args['myOption'] = myOptionSetting;
}    
  
 * Pass this in to the argumets hash, overriding the createParams
   function:

     var plink = new OpenLayers.Control.Permalink(null, null,
        {'createParams': myCreateArgs})

 * When something changes, call plink.updateLink();


> And then, when the page is reinstantiated, the argParser would call:
> 
>      if (this.callback) {
>          this.callback(args);
>      }

You can already create a customized ArgParser class and pass it to your
Permalink, but I'm not even sure that you should be parsing these things
in the argParser -- just parse them in your init() code instead, no need
to do any modifications or subclassing.

Regards,
-- 
Christopher Schmidt
MetaCarta