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GraphQL Schema from Introspection generator

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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

    <details> <summary>Introspection Query</summary>
        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.

    </details>
  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 :-(