Add a way to get response body for error responses

[marcinjahn]

I generated a client with Kiota, based on an OpenAPI spec, which does not specify error codes, hence errorMapping is empty in Kiota-generated client. The ApiException that Kiota throws contains just the status code and response headers. Is there any way to read the actual response body (as string) without modifying the Kiota-generated client code?

[baywet]

Hi @marcinjahn ,
Thanks for using kiota and for reaching out.
This is something we've been talking about a couple of times internally and waiting to see if there was customer demand for it.
On one hand we'd prefer the API descriptions to be improved so a model for the error is generated and the API consumer gets a better experience.
We're also concerned about the performance aspects, especially if the consumer doesn't dispose of the body.
On the other hand, we acknowledge that API producers and consumers are more often than not two different people, and that it's hard for consumers to funnel feedback to the producers.
Maybe what we could do is add a content type and content fields to the API exception type.
And only populate then if we were not able to deserialize to a generated type.
I'd like @sebastienlevert our PM to weight in on the experience aspect. He is on vacations for the next few weeks though.
In the meantime, you might be able to work this around by implementing your custom handler.

[marcinjahn]

Hi @baywet, exception containing the content would pretty much solve my issue.
Do you mean implementing a custom DelegatingHandler, or something else, Kiota-specific?

[baywet]

yes that what I meant

[sebastienlevert]

While I like the suggestion, it would not be an experience that would be seamless across all exceptions. Could we use the work we are doing around UntypedJson to support the body of the exception?

[baywet]

We could potentially decide to wrap the response into untyped json constructs when we don't have a mapping, and attach that to API error. Of course that assumes the response is JSON

[andrueastman]

Transferring issue as part of microsoft/kiota-dotnet#238

[andrueastman]

Moving this to main Repo to track this accross all languages for now.