GraphQL Codegen Gradle plugin

• Plugin Setup
• Plugin Options
• Sample Plugin Configuration
• Examples
  • GraphQL server code generation
  • GraphQL client code generation
• Different configurations for graphql schemas
• Convert generated Java classes to Kotlin classes

Plugin Setup

plugins {
  id "io.github.kobylynskyi.graphql.codegen" version "5.10.0"
}

Using legacy plugin application:

buildscript {
  repositories {
    maven {
      url "https://plugins.gradle.org/m2/"
    }
  }
  dependencies {
    classpath "io.github.kobylynskyi.graphql.codegen:graphql-codegen-gradle-plugin:5.10.0"
  }
}

apply plugin: "io.github.kobylynskyi.graphql.codegen"

Plugin Options

Please refer to Codegen Options

Sample Plugin Configuration

build.gradle:

graphqlCodegen {
    // all config options: 
    // https://github.com/kobylynskyi/graphql-java-codegen/blob/main/docs/codegen-options.md
    graphqlSchemas.includePattern = "schema\\.graphqls"
    outputDir = new File("$buildDir/generated")
    packageName = "com.example.graphql.model"
    customTypesMapping = [
        DateTime: "org.joda.time.DateTime",
        Price.amount: "java.math.BigDecimal"
    ]
    customAnnotationsMapping = [
        DateTime: ["@com.fasterxml.jackson.databind.annotation.JsonDeserialize(using = com.example.json.EpochMillisScalarDeserializer.class)"]
    ]
    modelNameSuffix = "TO"
}

// Automatically generate GraphQL code on project build:
compileJava.dependsOn 'graphqlCodegen'

// Add generated sources to your project source sets:
sourceSets.main.java.srcDir "$buildDir/generated"

You can also refer to build.gradle files in example projects: example-client/build.gradle , example-server/build.gradle

build.gradle.kts:

tasks.named<GraphQLCodegenGradleTask>("graphqlCodegen") {
    // all config options: 
    // https://github.com/kobylynskyi/graphql-java-codegen/blob/main/docs/codegen-options.md
    graphqlSchemaPaths = listOf("$projectDir/src/main/resources/graphql/schema.graphqls")
    outputDir = File("$buildDir/generated")
    packageName = "com.example.graphql.model"
    customTypesMapping = mutableMapOf(Pair("EpochMillis", "java.time.LocalDateTime"))
    customAnnotationsMapping = mutableMapOf(Pair("EpochMillis", listOf("@com.fasterxml.jackson.databind.annotation.JsonDeserialize(using = com.example.json.EpochMillisScalarDeserializer.class)")))
}

// Automatically generate GraphQL code on project build:
sourceSets {
    getByName("main").java.srcDirs("$buildDir/generated")
}

// Add generated sources to your project source sets:
tasks.named<JavaCompile>("compileJava") {
    dependsOn("graphqlCodegen")
}

Examples

GraphQL server code generation

example-server:

• Plugin configuration in build.gradle
• GraphQL Resolver classes that implement generated interfaces

GraphQL client code generation

example-client:

• Plugin configuration in build.gradle
• Building GraphQL request and parsing response using Spring RestTemplate
• Building GraphQL request and parsing response using RestAssured

Different configurations for graphql schemas

If you want to have different configuration for different .graphqls files (e.g.: different javaPackage, outputDir, etc.), then you will need to create separate gradle tasks for each set of schemas. E.g.:

task graphqlCodegenService1(type: GraphqlCodegenGradleTask) {
    graphqlSchemas.includePattern = "schema1\\.graphqls"
    outputDir = new File("$buildDir/generated/example1")
}

task graphqlCodegenService2(type: GraphqlCodegenGradleTask) {
    graphqlSchemas.includePattern = "schema2\\.graphqls"
    outputDir = new File("$buildDir/generated/example2")
}

Later on you can call each task separately or together:

• gradle clean graphqlCodegenService1 build
• gradle clean graphqlCodegenService2 build
• gradle clean graphqlCodegenService1 graphqlCodegenService2 build

Convert generated Java classes to Kotlin classes

1. Navigate in IntelliJ IDEA to the ./build/generated/graphql/ folder and press Cmd+Alt+Shift+K
2. Access generated classes as normal Kotlin classes.

Inspired by

swagger-codegen