[OpenLayers-Users] change WMS parameter on refresh

[Charles Galpin]

On Jun 1, 2012, at 4:41 PM, Eric Lemoine wrote:
> On Friday, June 1, 2012, Charles Galpin wrote:
> This is probably really simple but I'm drawing a blank.
> 
> I have a OpenLayers.Layer.WMS layer that I want to change a parameter each time it refreshes (on initial load, zoom, explicit refresh, whenever). In case you are curious ultimately I want to pass the map scale as part of  a parameter called "viewparams" which allows one to pass parameters to geoserver sql views. I can send a static value just fine from the value provided for params during construction, but need to make it dynamic.
> 
> So perhaps there is a pre-load event handler I can add to do the equivalent of mergeNewParams say? Thoughts?
> 
> Thanks,
> 
> 
> You can create a Layer.WMS subclass and overload getURL or getFullRequestString. Look at the OL code.

Eric, I just wanted to say thanks for the suggestion. This was perfect - I ended up overriding getURL since I had access to the bounds there (used to calculate the scale) and could add my params before the call to getFullRequestString.

Thanks again,
charles
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