Official Extension: GraphQL API Mocking

[oleg-nenashev]

Proposal

GraphQL becomes more and more popular, and services provide it along with classic REST APIs. It would be nice to support mocking of GraphQL requests with feature-rich request matching and response logic, including special extensions support

Implementation

• https://github.com/wiremock/wiremock-graphql-extension
• https://wiremock.org/docs/solutions/graphql/

References

• Website: https://graphql.org/
• GraphQL supports its own mocking https://graphql.org/blog/mocking-with-graphql/ , https://www.apollographql.com/docs/apollo-server/testing/mocking/
• MOVED to WireMock - Existing extension, in Kotlin: https://github.com/nilwurtz/wiremock-graphql-extension
  • Note: there are concerns about pulling in Kotlin runtime if it is a part of the core WireMock distributions

[kapishmalik]

@oleg-nenashev you can assign this issue to me. I will be working on the same.

[oleg-nenashev]

Done!

[kapishmalik]

I went through this and figured out one of the approaches and discussed it with Tom.

We will be parsing GraphQL queries and converting them to Document objects(https://github.com/graphql-java/graphql-java/blob/master/src/main/java/graphql/language/Document.java). There is already a pre-written equality library for comparing these Document objects https://github.com/com2ghz/graphql-query-compare. I will be using the same and comparing GraphQL queries/objects. We can also write our comparator if required instead of using this.

We can also convert this Document Object to JSON and can use a JSON comparator if required.

Since this approach requires graphql-java to be part of JAR, we'll be implementing this as a core extension.

[oleg-nenashev]

I am not sure this is what the equality matcher is what user would expect. GraphQL is basically a query with filters... a lot of them. So I do not see much value in comparing the requests with the reference, and I would rather expect processing on the handler level similar to a real GraphQL service.

One could also expect filtering by operation name (similar to HTTP request type), and maybe by arguments or some combinations.

[kapishmalik]

@oleg-nenashev I won't do any sort of exact match. I will be converting it to Document object which describes GraphQL query with all sort of filters. I would only be making necessary validations for equality to make sure that it corresponds to same query.

[oleg-nenashev]

Ack! Ok, then no objections

[oleg-nenashev]

As discussed with @kapishmalik and @tomakehurst , it should be rather implemented as an extension. I will move it to the Ecosystem repo until we have a better location

@kapishmalik could you please add the current design to the issues