Sample GraphQL Kotlin Server

Using the AWESOME GraphQL Kotlin libraries ❤️

How To

$ git clone https://github.com/rdbasu/demo.git
$ cd demo/
$ mvn clean install
$ mvn spring-boot:run

$ open http://localhost:8080/playground

☝️ will launch the GraphQL Playground

And you can start playing with your new Sample GraphQL Kotlin server 😍

Structure of the Project

++src
  ++main
    ++kotlin
      ++com.graphqlsummit.demo (this goes in application.properties, the packages which needs to be scanned)
        ++contexts
        ++enums (contains the enums)
        ++interfaces (contains the interfaces)
        ++models (contains the object types, input types, etc)
        ++mutations (contains the mutations)
        ++queries (contains the queries)
        ++DemoApplication.kt 
    ++resources
      ++application.properties

Things to Note

In pom.xml (To use the graphql-kotlin-spring-server)

<dependency>
  <groupId>com.expediagroup</groupId>
  <artifactId>graphql-kotlin-spring-server</artifactId>
  <version>1.2.3-SNAPSHOT</version>
</dependency>

In application.properties

graphql.packages=com.graphqlsummit.demo

An object type example code

data class Speaker(val name: String, val title: Title,
                   override val type: Type) : Attendee {
}

An ENUM example code

enum class Type {
    SPEAKER,
    GUEST,
    ORGANIZER
}

A QUERY example code

Implement the MARKER INTERFACE Query

class SpeakerQuery : Query {
    // A deprecated API, deprecated using Annotation: @Deprecated
    @Deprecated(message = "Forget this one", replaceWith = ReplaceWith("latestAndGreatest"))
    // Annotation @GraphQLDescription used to add description
    @GraphQLDescription("Sample Query for the GraphQL Summit 2019")
    fun getSpeaker(name: String): Speaker {
        return Speaker("Rohit Basu", Title.ARCHITECT, Type.SPEAKER)
    }

    @GraphQLDescription("The Latest & The Greatest")
    // Annotation @GraphQLName used to rename the API
    @GraphQLName("SomeRandomName")
    // Annotation @GraphQLIgnore used to ignore this API from the SCHEMA
    @GraphQLIgnore
    fun latestAndGreatest(name: String): Speaker {
        return Speaker("New & Improved Rohit", Title.ARCHITECT, Type.GUEST)
    }

    // A List Example
    @GraphQLName("Speakers")
    fun listSpeakers(): List<Speaker> {
        return listOf(Speaker("rohit basu", Title.ARCHITECT, Type.ORGANIZER),
                Speaker("rohit not so basu", Title.SLACKER, Type.GUEST),
                Speaker("rohit again basu", Title.SOFTWAREENGINEER, Type.SPEAKER))
    }

    // An example to show the usage of Custom Context
    @GraphQLName("RandomCustomContext")
    fun getCustomContext(@GraphQLContext context: CustomContext): Speaker? {
        println(context.custom)
        return null
    }
}

A DEPRECATED QUERY example code

Annotation used @Deprecated

// A deprecated API, deprecated using Annotation: @Deprecated
@Deprecated(message = "Forget this one", replaceWith = ReplaceWith("latestAndGreatest"))
// Annotation @GraphQLDescription used to add description
@GraphQLDescription("Sample Query for the GraphQL Summit 2019")
fun getSpeaker(name: String): Speaker {
    return Speaker("Rohit Basu", Title.ARCHITECT, Type.SPEAKER)
}

An example of Description code

Annotation used @GraphQLDescription

@GraphQLDescription("Sample Query for the GraphQL Summit 2019")

An example to IGNORE/exclude something from the SCHEMA code

Annotation used @GraphQLIgnore

@GraphQLIgnore
fun latestAndGreatest(name: String): Speaker {
    return Speaker("New & Improved Rohit", Title.ARCHITECT, Type.GUEST)
}

An example to rename something code

Annotation used @GraphQLName

@GraphQLName("RandomCustomContext")
fun getCustomContext(@GraphQLContext context: CustomContext): Speaker? {
    println(context.custom)
    return null
}

Create Custom Context code

Custom Context

data class CustomContext(val custom: String)

Custom Context Factory

@Component
class CustomGraphQLContextFactory : GraphQLContextFactory<CustomContext> {
    override suspend fun generateContext(request: ServerHttpRequest, response: ServerHttpResponse): CustomContext {
        return CustomContext("Just some Random Context")
    }
}

Using the Custom Context

@GraphQLName("RandomCustomContext")
fun getCustomContext(@GraphQLContext context: CustomContext): Speaker? {
    println(context.custom)
    return null
}

A MUTATION example code

Implement the MARKER INTERFACE Mutation

class SpeakerMutation : Mutation {
    @GraphQLDescription("A Sample Mutation")
    fun addSpeaker(name: String, title: Title): Speaker {
        println("the name: $name")
        println("the title: $title")
        return Speaker(name, title, Type.GUEST)
    }

    @GraphQLDescription("Adding Speaker as an Input Type")
    fun addSpeakerAsInputType(speaker: Speaker): Speaker {
        return Speaker(speaker.name, speaker.title, speaker.type)
    }
}

This documentation (WIP) will be made better soon. ⛅