add paging links tests

[vincentsarago]

trying to replicate issue from #194

cc @Kirill888

[Kirill888]

@vincentsarago thanks for looking into this, it could very well be an interaction with Magnum wrapper then

this is roughly how my current setup looks

prefix = "/stac"
_app = FastAPI(
        root_path=prefix,
        lifespan=lifespan,
)
# ... more setup
_api = StacApi(
        title=title,
        description=description,
        settings=settings,
        extensions=application_extensions,
        client=CoreCrudClient(pgstac_search_model=post_request_model),
        items_get_request_model=items_get_request_model,
        search_get_request_model=get_request_model,
        search_post_request_model=post_request_model,
        collections_get_request_model=collections_get_request_model,
        middlewares=middlewares,
        app=_app,
        **kw,
)

# AWS Lambda wrapper
handler = Mangum(
        app,
        api_gateway_base_path=app.root_path,
        lifespan="off",
        text_mime_types=text_mime_types,
 )

In the debugger I see that _api.app.router.prefix = '', should I expect it to be /stac instead?

[vincentsarago]

@Kirill888

In the debugger I see that _api.app.router.prefix = '', should I expect it to be /stac instead?

I wonder if this is because we don't set prefix when registering the router in https://github.com/stac-utils/stac-fastapi/blob/main/stac_fastapi/api/stac_fastapi/api/app.py#L440C9-L440C32

🤔

[Kirill888]

@vincentsarago I'm not too familiar with FastAPI or web programming in Python in general, but my understanding is this

• FastAPI.root_path is about telling the app sitting behind a reverse proxy what URL the user is using to access it. And this URL can have extra components on the left side that is used by the proxy for routing but is removed by the proxy when forwarding to the APP, e.g. root_path=/internal/api/v1.2. See Proxy with a stripped path prefix FastAPI docs.
• While Router.prefix is about gluing together different parts of the API within a single app, e.g. prefix=/collections

So I think in the test you should NOT set prefix= on the Router at all and invoke these methods with URLs without root_path= component present, yet the output should contain root_path prefix in all the URLs back to self.

[vincentsarago]

So I think in the test you should NOT set prefix= on the Router at all and invoke these methods with URLs without root_path= component present, yet the output should contain root_path prefix in all the URLs back to self.

The test added in this PR test endpoint with/without root-path or prefix (2x2 matrix)

if we look at https://github.com/encode/starlette/blob/a7d0b14c7378aa2e95b0b13583fe0dadace363be/tests/test_routing.py#L568-L575, it seems that we have to call /{root-path}/{router-prefix}/{endpoint-path} within the TestClient 🤷

[Kirill888]

@vincentsarago see #201

With that change to the test, I DO get test failure for link generation on my fork:

https://github.com/Kirill888/stac-fastapi-pgstac/actions/runs/13361242617/job/37311202071?pr=1#step:7:1068

=========================== short test summary info ============================
FAILED tests/api/test_links.py::tests_app_links[/api/v1] - AssertionError: assert 'http://stac.io/search' == 'http://stac.io/api/v1/search'
  
  - http://stac.io/api/v1/search
  ?                -------
  + http://stac.io/search
====== 1 failed, 888 passed, 25 skipped, 8 warnings in 359.23s (0:05:59) =======
Error: Process completed with exit code 1.

[Kirill888]

see #201 , but this should also work:

Suggested change

	endpoint_prefix = root_path + prefix
	url_prefix = "http://stac.io" + endpoint_prefix
	endpoint_prefix = prefix
	url_prefix = "http://stac.io" + root_path + endpoint_prefix

we want to model situation when root_path is dropped by the reverse proxy, but needs to be present in the output links as this is the only way to reach the API.

[vincentsarago]

🤔 I'm not sure to get this to be honest

In all cases, the client should be called {root-path}/{prefix}/endpoint as shown in https://github.com/encode/starlette/blob/a7d0b14c7378aa2e95b0b13583fe0dadace363be/tests/test_routing.py#L573-L575

[Kirill888]

🤔 I'm not sure to get this to be honest

In all cases, the client should be called {root-path}/{prefix}/endpoint as shown in https://github.com/encode/starlette/blob/a7d0b14c7378aa2e95b0b13583fe0dadace363be/tests/test_routing.py#L573-L575

I don't understand how you come to this conclusion from that one test alone. I'm just trying to replicate the scenario I see in the debugger of a real system. Omitting the root path in the call to the test client still routes to the endpoint in question, but this time with the request object behaving the same way as in the real system behind a reverse proxy that removes routing prefix.

[vincentsarago]

ok I think we're good with this now

self.base_url would return http://0.0.0.0/{root-path}/{router-prefix}/collection while self.url.path returns {/router-prefix}/collections so using self.request.base_url gives the correct result

self.request.url will return http://0.0.0.0/{root-path}/collection because it doesn't know the router-prefix (weird configuration in stac-fastapi it self, because we don't mount the router with the prefix set 🤷)

[vincentsarago]

This feels over engineered but it's the only way I could find to make it works 🤷

[hrodmn]

This feels like a FastAPI problem to me since self.request.url is not respecting the root_path setting, but this solution fixes the link problem!

[vincentsarago]

I'm going to merge this PR and make a new release.

I believe this fix most of the issue with root-path/prefix links.

Please feel free to open new issues if you encounter more issues 🙏