`getProviders` returns empty array if delegated routing server returns Content-Type header that is not "application/json" exactly

[Rinse12]

What's the problem

Delegated routing client is too rigid with its expectation of Content-Type header value. In this line:
https://github.com/ipfs/helia-delegated-routing-v1-http-api/blob/main/packages/client/src/client.ts#L142

If the value is not "application/json", then it will return an empty array for getProviders, with no error logs or anything. Even if the status was 200.

We have a routing server that returns Content-Type="application/json; charset=utf-8", and clients are not able to consume its providers JSON.

Reproduction

  const client = createDelegatedRoutingV1HttpApiClient("https://peers.pleb.bot");
  

   const generator = client.getProviders(CID.parse("QmdjSj3KGquq2hucok1F7fNRmvi9DhZidh9NsRpdk3Q553"), {
    filterAddrs: undefined,
    filterProtocols: undefined,
  });
  
  const firstValue = await generator.next(); // undefined, even though the routing server responds with at least one provider

  // No errors at all as well

[SgtPooki]

thank you for filing this issue, that is a great find. We shouldn't be comparing a strict equals for the content-type header in the response. We should be using .includes() or better

[Nkovaturient]

hey @SgtPooki , if (contentType && contentType.includes('application/json')) will solve this issue alongside adding test cases in the repository to verify that the updated logic works for Content-Type: application/json; application/json; charset=utf-8 ---

TestCases:

Validating the behavior of the getProviders under various Content-Type headers:
Exact match: application/json.
Includes charset: application/json; charset=utf-8.
NDJSON: application/x-ndjson.
Test error handling for invalid or missing CIDs and provider retrieval for both single and multiple providers.

[SgtPooki]

@Nkovaturient I think that's a good fix, especially with the additional testing to confirm.. but we should probably use startsWith instead of includes because that media-type should always be at the beginning of the string.

[Nkovaturient]

@SgtPooki agree!

[Nkovaturient]

Hey @SgtPooki ,
I have worked on this issue and created a PR #155 with efficiency, kindly review it and guide me further. 😄