graphql-ws-kotlin

Unfinished / work in progress, but should be somewhat usable! Feedback welcome.

Example demo: http://graphql.holak.net/

---

This library makes it easy to write GraphQL servers that support subscriptions via WebSockets. It uses graphql-java to execute GraphQL queries.

The protocol for subscriptions is taken from apollographql/subscriptions-transport-ws, which you can use as a client (see the frontend in example/src/main/resources/frontend).

Getting started

Run the example

• Run the example project (from the IDE, or by running ./gradlew run in the example directory), then open your browser at http://localhost:4567/

• You can see a live demo at http://graphql.holak.net/

Use the library

For now, there is no released version, so you can only use the current snapshot. Add the jitpack.io repository to your build.gradle.

repositories {
    maven { url "https://jitpack.io" }
}

Then add the dependency

compile 'com.github.peterholak:graphql-ws-kotlin:-SNAPSHOT'

What still needs to be done

• improved documentation, code examples in README
• more robust exception handling (consistent/predictable behavior no matter where an exception occurs)
• more logging
• performance improvements
  • currently, it runs the subscription query for every subscriber, even if the query is the same
  • support for batching notifications would be nice
  • as far as I can tell, variables are also needlessly coerced into the correct type on every publish() (it is sufficient to do this just once)
  • use asynchronous GraphQL query execution in publish()
• thread safety
• tests for more cases (especially write tests where the stubs currently are)
• the setup is still a bit too complicated, untangle the cyclical dependencies (see Main.kt in the example project)
• maybe support for writing clients (including Kotlin JS target)
• all the other TODOs in the code (other operations, keep-alive, etc.)
• javadoc for most of the classes
• maybe support for using method arguments in filters, instead of using maps (see the publish for filteredPublishedText in the example project)