GraphQL Schema from Introspection generator

This library helps you generate GraphQL Schema (also called GraphQL DSL or SDL) based on Introspection Query response. It's useful when you use graphql-java and Code First approach and want to migrate to Schema First approach.

How to use it?

1. Download Command Line Tool from releases page.

2. Run java -jar graphql-schema-from-introspection-generator-cli-X.X.X.jar input.json output.graphqls

   File input.json should contain the output of GrpahQL Introspection query. If you don't have this file yet, you can use one from: core/src/test/resources/testdata/

3. In output.graphqls you will find generated GraphQL Schema.

How get Introspection Query result?

1. Run your application.

2. Run

   Introspection Query

       query IntrospectionQuery {
         __schema {
           queryType { name }
           mutationType { name }
           subscriptionType { name }
           types {
             ...FullType
           }
           directives {
             name
             description
             locations
             args {
               ...InputValue
             }
           }
         }
       }
     
       fragment FullType on __Type {
         kind
         name
         description
         fields(includeDeprecated: true) {
           name
           description
           args {
             ...InputValue
           }
           type {
             ...TypeRef
           }
           isDeprecated
           deprecationReason
         }
         inputFields {
           ...InputValue
         }
         interfaces {
           ...TypeRef
         }
         enumValues(includeDeprecated: true) {
           name
           description
           isDeprecated
           deprecationReason
         }
         possibleTypes {
           ...TypeRef
         }
       }
     
       fragment InputValue on __InputValue {
         name
         description
         type { ...TypeRef }
         defaultValue
       }
     
       fragment TypeRef on __Type {
         kind
         name
         ofType {
           kind
           name
           ofType {
             kind
             name
             ofType {
               kind
               name
               ofType {
                 kind
                 name
                 ofType {
                   kind
                   name
                   ofType {
                     kind
                     name
                     ofType {
                       kind
                       name
                     }
                   }
                 }
               }
             }
           }
         }
       }
   

   This query based on Introspection Queries in graphql-java and GraphiQL projects.

3. Store result in a file and use Command Line tool for generating the schema (See: How to use it?).

Release Notes

Release notes: docs/release-notes.md

How to build project?

1. Clone repo
2. Run ./gradlew build
3. You can find Command Line Tool in cli/build/libs
4. You can find core library in core/build/libs

Another usage

You can use the core library in your projects if you want. Just add a dependency (in Gradle):

compile group: 'io.github.mstachniuk', name: 'graphql-schema-from-introspection-generator-core'

How to contribute?

Please Send PR's, issues and feedback via GitHub.

Alternatives

During finishing this project I found that similar tool already exists in graphql-java project, see IntrospectionResultToSchema class.

Another possibility is to use graphql-js and this code snippet (NodeJS):

const graphql = require("graphql");
const schema = require("path/to/schema.json");

const clientSchema = graphql.buildClientSchema(schema.data);
const schemaString = graphql.printSchema(clientSchema);
console.log(schemaString)

Unfortunately, I didn't know that before :-(