Fluent query API

[martinbonnin]

This PR serves as a RFC for a new ApolloCall type to make the API more fluent. It's hopefully the last big API-breaking change now that #3301 is done. An ApolloCall is a simple wrapper around a (ApolloRequest + ApolloClient). It can be configured, is self contained and contains everything needed to execute the query and return a response.

It's slightly more verbose if no customization is done (having to add the extra .execute()) but it's a lot less verbose as soon as any customization is required.

I personally like how it makes tests easier to write but the more feedback we get, the better.

Current code:

val request = ApolloRequest.Builder(HeroQuery()).fetchPolicy(FetchPolicy.NetworkOnly).build()
val response = apolloClient.query(request)

Fluent (new) code:

val response = apolloClient.query(HeroQuery())
        .fetchPolicy(FetchPolicy.NetworkOnly)
        .execute()

This API is also closer to what was done in 2.x and plays nicer with RxJava:

// Before
val response = Rx2Client(apolloClient).query(query).blockingGet()

// After
val response = apolloClient.query(query).rxSingle().blockingGet()

On the drawbacks side, it's one more type (ApolloCall) to maintain that needs to implement HasMutableExecutionContext. It should cause any performance regression but it's more code and increases the API surface. I've thought of making ApolloRequest internal to reduce the API surface a bit but it's still used as part of the ApolloInterceptor API so it's not really possible.

Let us know what you think!

[BoD]

I like it!

It's slightly more verbose if no customization is done (having to add the extra .execute()) but it's a lot less verbose as soon as any customization is required.

Indeed we can see in the tests that the custom cases look a lot nicer! For the simple case, we could add a executeQuery fun on ApolloClient which does .query().execute().

• Pros:
  • shorter
  • if most users would end up making this extension anyway (but not sure that's fact), let's have it in the lib
• Cons:
  • now you have 2 ways to query ;)
  • one more API
  • probably useful only in simple projects?

[martinbonnin]

we could add a executeQuery fun on ApolloClient

Let's see the feedback we have until committing to more API? It's always easier to add than remove...