Unable to pass `errorMapping` to send methods in `requestBuilder`

[maxrichter-dyna]

The generated requestBuilder always passes an empty map to the requestAdapter for the errorMapping:

Future<Post?> postAsync(Post body, [void Function(RequestConfiguration<DefaultQueryParameters>)? requestConfiguration]) async {
        var requestInfo = toPostRequestInformation(body, requestConfiguration);
        return await requestAdapter.send<Post>(requestInfo, Post.createFromDiscriminatorValue, {});
                                                                                             /* ↑ errorMapping */
}

The default HttpClientRequestAdapter could handle the errorMapping, but a missing errorMapping will always cause an ApiException to be thrown, which has to be handled with a trycatch block.

[ricardoboss]

There are no error mappings generated in the code you linked, because the spec doesn't specify any errors that could be returned from this endpoint: https://github.com/microsoft/kiota-samples/blob/455c738c19740348e63ff3222a5679520f71e2d6/get-started/quickstart/posts-api.yml#L52

Can you share an example spec where this is not the case (that is, where error responses are defined) and they are not generated?

[maxrichter-dyna]

@ricardoboss thank you for the quick response and sorry for my delayed answer.

After some more tests I was able to find out the specific case which i expected to work but doesnt.

Kiota Version: 1.28.0+57130b1b1db3bc5c060498682f41e20c8ae089f2

This example:

/posts:
  post:
    responses:
      '400':
        description: Bad request
        content:
          application/json:
            schema:
              type: object

Generates the following postAsync function:

Future<Iterable<int>?> postAsync([void Function(RequestConfiguration<DefaultQueryParameters>)? requestConfiguration]) async {
    var requestInfo = toPostRequestInformation(requestConfiguration);
    final errorMapping = <String, ParsableFactory<Parsable>>{
        '400' :  Posts400Error.createFromDiscriminatorValue,
    };
    return await requestAdapter.sendPrimitiveCollection<int>(requestInfo, errorMapping);
}

While this route:

/posts:
  post:
    responses:
      '400':
        description: Bad request

Does not generate any errorMapping code, even though it should be possible to handle errors only by their status.

Future<Iterable<int>?> postAsync([void Function(RequestConfiguration<DefaultQueryParameters>)? requestConfiguration]) async {
    var requestInfo = toPostRequestInformation(requestConfiguration);
    return await requestAdapter.sendPrimitiveCollection<int>(requestInfo, {});
}

I added the code for the explanation/reproduction here: https://github.com/maxrichter-dyna/kiota-errormapping-repro

[ricardoboss]

Does not generate any errorMapping code, even though it should be possible to handle errors only by their status.

AFAIK, this is not supported by Kiota. Kiota only handles a response when it can deserialize a body (even if it is empty). This is because the error needs to be thrown once the expected status code is read. If there is no body, nothing can be thrown.

I think you can work around this by adding a text/plain response content. IIRC this will result in an empty string for an empty body.

Edit:
Yeah, here in the docs it says explicitly:

An error mapping is only considered valid if the response has a schema of type object and at least one field.