/cog/viewer does not work behind a reverse proxy

[morandd]

I have a TiTiler app running in Kubernetes , using a Traefik reverse proxy for HTTPS and the virtual domain at [titiler.mycompany.com]

The /cog/viewer endpoint does not work. The MapLibre instance is requesting information about the GeoTIFF I'm viewing and dispatching an AJAX request like:

http://localhost:5020/cog/info.geojson?url=[URL to my .tif]

This of course refers to "localhost:5020", which is the Docker instance, instead of https://titiler.mycompany.com

I believe the issue lies at least in lines 36-43 in

https://github.com/developmentseed/titiler/blob/main/src/titiler/extensions/titiler/extensions/viewer.py

There I believe the "info.geojson" is defined relative to the request URL, which is the URL as received behind the reverse proxy. For example lines
40: "info_endpoint": factory.url_for(request, "info_geojson"),
41: "statistics_endpoint": factory.url_for(request, "statistics"),

A possible solution would be to add an optional environment variable "TITILER_BASE_URL". Then a user could set a value like "https://titiler.mycompany.com". Then, adjust line 40, 41, and other affected lines, to use this TITILER_BASE_URL if provided otherwise the "request" url as the base.

[vincentsarago]

Hi @morandd

The reverse proxy issue is something that has been reported multiple times but I believe each time the real problem was solved on the proxy side with specific configuration

#1102
#342
#345

in the docker-compose config there is a proxy setup we run to test titiler https://github.com/developmentseed/titiler/blob/main/docker-compose.yml#L56-L69 and it seems to work fine.

If there is an issue, I would suspect it would be on starlette or on uvicorn side