Enable CORS for BCGW Overlay / Base Map requests

[bferguso]

Overlays and base maps are served by BCGW WMS, which is not at the same domain as the Arches applications. Need to enable CORS in the headers to allow overlay/base map requests.

For Dev the workaround is to disable the CORS headers checking.

Created a sub-class of the TileserverProxyView which redirects to multiple servers based on the tile server request.

A request parameter called source is used to direct the traffic to the appropriate tile server (WMS).

Valid source values are:

• local (directs to the pg_tileserv instance on the application server)
• maps - directs to maps.gov.bc.ca
• openmaps - directs to openmaps.gov.bc.ca

If no value is specified the default is openmaps.gov.bc.ca.

Outbound traffic to the WMSs is through a forward proxy configuration.

[bferguso]

Potential option is to use Arches proxy to retrieve this data. Do headers follow through?

[bferguso]

BCRHP deployed to LEGACY. Waiting to hear about window to refresh Fossils.

[bferguso]

Applied fix to allow proxying of tiles from local server which does not require/allow outgoing proxy and BCGW tileserver requests which requires an outgoing proxy.

[bferguso]

Marking as complete and now in Prod.