Alternative to graphql_ppx?

[swac]

Issue Labels

• has-reproduction
• feature
• docs
• blocking
• good first issue

It seems all of the existing examples and documentation suggest using graphql_ppx to parse queries and responses. graphql_ppx currently has significant limitations, such as not supporting interfaces and inline fragments, however. Is there any alternative to using graphql_ppx with Reason Apollo? If so, it would be great to have an example documented. If not, is there any workaround for querying a GraphQL API that uses interfaces?

[kgoggin]

Yep, you can definitely use reason-apollo without graphql_ppx, though I agree it's not super obvious. Basically, if you're using graphql_ppx, it creates a module that conforms to the Config type defined here. So if you don't want to use graphql_ppx, you can just definite your own Config module with the query, type t, and parse function.

I wrote about why/how I'm doing Apollo in Reason without graphql_ppx. Essentially I define Reason types that align to all of my GraphQL types, and then a QueryRoot type that matches GraphQL's Query. Then all of my query config modules have type t = QueryRoot.t and parse is a set function that takes the JSON response from apollo and turns it into a QueryRoot.t. Mutations are a little different, but not to dissimilar.

I prefer this approach because I can reuse types everywhere, and because of the limitations you mentioned with graphql_ppx regarding interfaces and inline fragments. I've actually got all of my queries and mutations defined in .graphql files, which I also prefer because I can lint them!

Hope that's helpful. I'm unsure about the best way to document any of this in this repo because it's a pretty significant difference in the way you work with it.

[baransu]

Soon (I hope), graphql_ppx will have support for interfaces (not in 100% but for most of the use cases). Here you can check the PR: mhallin/graphql_ppx#56 And if you're interested in some functionality that's missing in graphql_ppx please create an issue or submit a PR 🙂

[Enalmada]

@kgoggin That is an amazing article....wow. Would you consider putting up a non graphql_ppx version of the swapi example with concepts in your article? I think that might give the community an appropriate place to watch/discuss the current state of things with issues/pull as things change. Plus, as a new user, being able to fire up a fully functional example and see all the setup details (linting, pattern matching, etc) is invaluable and helps get others on the bandwagon.

[swac]

@baransu Thanks, I hadn't seen that! I actually checked the graphql_ppx repo before creating this issue and saw that there's already an issue regarding interface support: mhallin/graphql_ppx#47. I didn't want to create a redundant issue, so I filed this one.

[baransu]

@swac graphql_ppx starting from version 0.2.8 have interfaces support.