base_url used to build the urls without root_path

[ccancellieri]

Hi all,
I need to have multiple instances of this api under the same fastAPI and I'm trying to understand why base_url has been used to generate urls not using also:
f"{base_url}/{request.scope.get("root_path")}

This is preventing me to mount the application under a specific fastAPI path: all the generated urls are not shipping the root_path infact.

It works with a fixed prefix but it is kind of hardcoded routing base url which prevents me to properly use fastAPI with this library.

It would be great if we could centralise the base url management here to also use the root_path from the scope:
def get_base_url(request: Request) -> str:

My goal is to mount multiple times this library to be able to have a first level of catalogs in a single application:

"links": [
{
"rel": "self",
"type": "application/json",
"href": "http://localhost:8080/catalogs/catalog_1/"
},
{
"rel": "root",
"type": "application/json",
"href": "http://localhost:8080/catalogs/catalog_1/"
},
{
"rel": "data",
"type": "application/json",
"href": "http://localhost:8080/catalogs/catalog_1/collections"
},
{
"rel": "conformance",
"type": "application/json",
"title": "STAC/WFS3 conformance classes implemented by this server",
"href": "http://localhost:8080/catalogs/catalog_1/conformance"
},
{
"rel": "search",
"type": "application/geo+json",
"title": "STAC search",
"href": "http://localhost:8080/catalogs/catalog_1/search",
"method": "GET"
},

Related problem:
stac-utils/stac-fastapi-elasticsearch-opensearch#308 (comment)

Related questions: why we are using the state of the application to save it?
app.state.router_prefix=....

What do you think?

[vincentsarago]

Hi @ccancellieri,

I'm not sure to fully get everything. We've had numerous report related to prefix and route_path and usually it always comes down to proxy settings https://github.com/stac-utils/stac-fastapi/issues?q=is%3Aissue+root_path+is%3Aclosed

Could you be a bit more precise how you are mounting multiple stac-fastapi application?

root_path isn't a settings option in the current stac-fastapi application, I've created #769 to resolve this, but I'm not sure this will fix your issue

Related questions: why we are using the state of the application to save it?

This is a legacy code and I will be worry to change this logic for now

[ccancellieri]

Hi @ccancellieri,

I'm not sure to fully get everything. We've had numerous report related to prefix and route_path and usually it always comes down to proxy settings https://github.com/stac-utils/stac-fastapi/issues?q=is%3Aissue+root_path+is%3Aclosed

Could you be a bit more precise how you are mounting multiple stac-fastapi application?

This is what I'm trying to obtain:
https://github.com/ccancellieri/stac-fastapi-elasticsearch-opensearch/blob/c838d13d5f349e209cc6198781fa488173fc84d8/stac_fastapi/elasticsearch/stac_fastapi/elasticsearch/app.py#L150

... and here is why:
stac-utils/stac-fastapi-elasticsearch-opensearch#308 (comment)

root_path isn't a settings option in the current stac-fastapi application, I've created #769 to resolve this, but I'm not sure this will fix your issue

Thank you for this!

[vincentsarago]

This is what I'm trying to obtain:
https://github.com/ccancellieri/stac-fastapi-elasticsearch-opensearch/blob/c838d13d5f349e209cc6198781fa488173fc84d8/stac_fastapi/elasticsearch/stac_fastapi/elasticsearch/app.py#L150

Could you just use the router_prefix option for this?

[ccancellieri]

Unfortunately Collections uses the base_url to calculate the links:

stac-fastapi/stac_fastapi/types/stac_fastapi/types/links.py

Line 50 in 4491fa1

href=urljoin(self.base_url, f"collections/{self.collection_id}"),

and router_prefix is not affecting this.
I could be wrong but debugging this is what I see.
I'm testing several options with no success

I think the unique option to correctly mount as a catalog this application is to use root_path or request.url to build the links to make it working behind a mounted context.

Current code:
urljoin(self.base_url,f"collections/{self.collection_id}")

Result (wrong):

'http://localhost:8080/collections/1e8874ad-d2b1-4eba-a881-7c8f092adffd'

Working but clunky:
urljoin(f"{self.base_url}/{self.request.scope.get('root_path')}", f"collections/{self.collection_id}")

Result (correct):
'http://localhost:8080/catalogs/catalog_1/collections/1e8874ad-d2b1-4eba-a881-7c8f092adffd'

Working and flexible:
urljoin(self.url, f"collections/{self.collection_id}")

Result (correct):
'http://localhost:8080/catalogs/catalog_1/collections/1e8874ad-d2b1-4eba-a881-7c8f092adffd'

thanks again.

I could try to produce a fix and a POC if it coud help.

[vincentsarago]

🤔 in https://github.com/stac-utils/stac-fastapi/pull/769/files#diff-1eec7e8fe8a9e8a3a1060ba4ff8263360ccaca01a419ab18179e33379a097d35 we added a test to make sure the root_path was properly set to the base_url so I'm not quite sure what to do next

[ccancellieri]

Dear @vincentsarago thank you so much for your great effort.
I think you correctly now passed the root_path.
Unfortunately this does't solve my specific problem since root_path is correctly set but unused here:

stac-fastapi/stac_fastapi/types/stac_fastapi/types/requests.py

Line 6 in 4491fa1

def get_base_url(request: Request) -> str:

using root_path instead of the state of the app here is key to solve the wrong generation of the urls in all the extensions.

I think I could produce a pull request to show the use case to help you to understand the specific use case (multiple intance of a stac-fastapi mount).

This issue is resolving a quite important problem to me: having /catalogs/{catalog_name}/... prepended to each link for each instance of a stac_fastapi instance.

You could proceed merging this improvement as it could be used as base for the changes to the get_base_url, I will then be able to discuss this change in a specific issue.