moleculer-apollo-server

Apollo GraphQL server mixin for Moleculer API Gateway

Features

Install

npm i moleculer-apollo-server moleculer-web@next graphql

Usage

This example demonstrates how to setup a Moleculer API Gateway with GraphQL mixin in order to handle incoming GraphQL requests via the default /graphql endpoint.

"use strict";

const ApiGateway 	= require("moleculer-web");
const { ApolloService } = require("moleculer-apollo-server");

module.exports = {
    name: "api",

    mixins: [
        // Gateway
        ApiGateway,

        // GraphQL Apollo Server
        ApolloService({

            // Global GraphQL typeDefs
            typeDefs: ``,

            // Global resolvers
            resolvers: {},

            // API Gateway route options
            routeOptions: {
                path: "/graphql",
                cors: true,
                mappingPolicy: "restrict"
            },

            // https://www.apollographql.com/docs/apollo-server/v2/api/apollo-server.html
            serverOptions: {
                tracing: true,

                engine: {
                    apiKey: process.env.APOLLO_ENGINE_KEY
                }
            }
        })
    ]
};

Start your Moleculer project, open http://localhost:3000/graphql in your browser to run queries using graphql-playground, or send GraphQL requests directly to the same URL.

Define queries & mutations in service action definitions

module.exports = {
    name: "greeter", 

    actions: {
        hello: {
            graphql: {
                query: "hello: String"
            },
            handler(ctx) {
                return "Hello Moleculer!"
            }
        },
        welcome: {
            params: {
                name: "string"
            },
            graphql: {
                mutation: "welcome(name: String!): String"
            },
            handler(ctx) {
                return `Hello ${ctx.params.name}`;
            }
        }
    }
};

Generated schema

type Mutation {
  welcome(name: String!): String
}

type Query {
  hello: String
}

Resolvers between services

posts.service.js

module.exports = {
    name: "posts",
    settings: {
        graphql: {
            type: `
                """
                This type describes a post entity.
                """			
                type Post {
                    id: Int!
                    title: String!
                    author: User!
                    votes: Int!
                    voters: [User]
                    createdAt: Timestamp
                }
            `,
            resolvers: {
                Post: {
                    author: {
                        // Call the `users.resolve` action with `id` params
                        action: "users.resolve",
                        rootParams: {
                            "author": "id"
                        }
                    },
                    voters: {
                        // Call the `users.resolve` action with `id` params
                        action: "users.resolve",
                        rootParams: {
                            "voters": "id"
                        }
                    }
                }
            }
        }
    },
    actions: {
        find: {
            //cache: true,
            params: {
                limit: { type: "number", optional: true }
            },
            graphql: {
                query: `posts(limit: Int): [Post]`
            },
            handler(ctx) {
                let result = _.cloneDeep(posts);
                if (ctx.params.limit)
                    result = posts.slice(0, ctx.params.limit);
                else
                    result = posts;

                return _.cloneDeep(result);
            }
        },

        findByUser: {
            params: {
                userID: "number"
            },
            handler(ctx) {
                return _.cloneDeep(posts.filter(post => post.author == ctx.params.userID));
            }
        },
    }
};

users.service.js

module.exports = {
    name: "users",
    settings: {
        graphql: {
            type: `
                """
                This type describes a user entity.
                """			
                type User {
                    id: Int!
                    name: String!
                    birthday: Date
                    posts(limit: Int): [Post]
                    postCount: Int
                }
            `,
            resolvers: {
                User: {
                    posts: {
                        // Call the `posts.findByUser` action with `userID` param.
                        action: "posts.findByUser",
                        rootParams: {
                            "id": "userID"
                        }
                    },
                    postCount: {
                        // Call the "posts.count" action
                        action: "posts.count",
                        // Get `id` value from `root` and put it into `ctx.params.query.author`
                        rootParams: {
                            "id": "query.author"
                        }
                    }                    
                }
            }			
        }
    },
    actions: {
        find: {
            //cache: true,
            params: {
                limit: { type: "number", optional: true }
            },
            graphql: {
                query: "users(limit: Int): [User]"
            },
            handler(ctx) {
                let result = _.cloneDeep(users);
                if (ctx.params.limit)
                    result = users.slice(0, ctx.params.limit);
                else
                    result = users;

                return _.cloneDeep(result);
            }
        },

        resolve: {
            params: {
                id: [
                    { type: "number" },
                    { type: "array", items: "number" }
                ]
            },
            handler(ctx) {
                if (Array.isArray(ctx.params.id)) {
                    return _.cloneDeep(ctx.params.id.map(id => this.findByID(id)));
                } else {
                    return _.cloneDeep(this.findByID(ctx.params.id));
                }
            }
        }
    }
};

Examples

• Simple
  • npm run dev
• Full
  • npm run dev full
• Full With Dataloader
  • set DATALOADER environment variable to "true"
  • npm run dev full

Test

$ npm test

In development with watching

$ npm run ci

Contribution

Please send pull requests improving the usage and fixing bugs, improving documentation and providing better examples, or providing some testing, because these things are important.

License

The project is available under the MIT license.

Contact

Copyright (c) 2018 MoleculerJS