Unable to load correctly existing WMS from URL in WMS Capabilities demo

[ThomasG77]

Steps to reproduce

• I go to https://viglino.github.io/ol-ext/examples/layer/map.wmscapabilities.html
• I paste in the form for url https://services.sandre.eaufrance.fr/geo/mdo
• I click Search
• The UI displays a popup where I choose Hydroecoregions1
• I click on "Load" in the UI and it displays the layer
• The URL change due to the action. Instead of default, it's now https://viglino.github.io/ol-ext/examples/layer/map.wmscapabilities.html?lon=4.798350&lat=47.480930&z=4.8&url=https%3A%2F%2Fservices.sandre.eaufrance.fr%2Fgeo%2Fmdo%3Flanguage%3Dfre%26&layer=Hydroecoregion1
• I cut & paste the URL in another tab/window of the browser and validate the URL. The layer does not seems to appear.

I would expect with what look like a permalink (but maybe not !?) that I could see the layer displayed in the new browser tab or window.

I have a dirty implementation where I do not rely on capabilities to see the layer e.g https://labs.webgeodatavore.com/partage/wms_permalink.html#map=5.30%2F2.53%2F46.64&layer=Hydroecoregion1&url=https%3A%2F%2Fservices.sandre.eaufrance.fr%2Fgeo%2Fmdo but I want best of both world e.g the capabilities UI and the ability to share when I have an existing layer already added.

Clues about the bug

After some inspection, it seems to be a bug as in line https://github.com/Viglino/ol-ext/blob/master/examples/layer/map.wmscapabilities.html#L157, I see a reference to a loadLayer function. When I look at exact function at https://github.com/Viglino/ol-ext/blob/master/src/control/WMSCapabilities.js#L871 and I also debug using breakpoint with my URL using browser DevTools, I see the issue is that there is no recursive search.

In my particular case, there is a loop in the cap.Capability.Layer.Layer.forEach that contains only one layer.
The problem is that cap.Capability.Layer.Layer[0].Layer does contain 21 layers. Without a recursive approach, we miss some available layers and that as the loop never find the "right" layer, it does not add it (because it does a check on capability before adding the layer)

The issue is now to choose if recursive layer search is wanted and if yes, how to implement it properly.

[Viglino]

Yes the loadLayer method only check the parent layers.
I fix it by looking layers recursively. 254429b
Now it's working fine 😄

[ThomasG77]

Fix fine for me. Closing.