Skip to content

Latest commit

 

History

History
 
 

beeradvisor

README.md

BeerAdvisor: A graphql-java example with Spring Boot and JPA

The application consists of two Spring Boot Apps:

  1. The shopservice. This service manages a list of shops (locations and beers they sell). It provides a REST API to query the shops. For simplicity there is no way to modify shops and the actual data is stored in memory only (no database). The purpose of the shop service is to demo, how to access a rest endpoint from GraphQL.

  2. The beeradvisor. This is the backend for our application. It manages Beers, Ratings and Users and provides a GraphQL API for our domain. It also add the Shops from the shopservice to our GraphQL API by connecting to that service via REST.

The third project in this repository is the React-based frontend.

Configuration

Ports

Before starting the services please make sure that the following ports are not in use:

  • port 9000 for the BeerAdvisor backend
  • port 9010 for the ShopService
  • port 9080 for the frontend (webpack dev server)

Database

  • When you start the BeerAdvisor backend an embedded h2 database will be started, that writes it's content to ~/h2/beer-rating. You can change that in the application.properties file.

Users/Login

  • In order to add Ratings (using GraphQL Mutations) you need to login via the UI. You can simply use any firstname of any author that already has submitted a rating (for example alessa, waldemar, lauren)

Starting

There are three bash scripts in this folder that helps you starting the application:

  1. 01_run_shopservice.sh
  2. 02_run_beeradvisor.sh
  3. 03_run_frontend.sh

When all three apps are running, you can access the web application at

  • http://localhost:9080

Alternatively you can run the application using gradle or your IDE:

Run shopservice

  1. Go to the shopservice directory
  2. ./gradlew bootRun
    • OR - Just run main method in ShopServiceApplication class from your IDE (for example from SpringBoot launcher in IDEA)

Run beeradvisor Application

  1. Go to the beeradvisor directory
  2. ./gradlew bootRun
    • OR - Just run main method in BeerAdvisorApplication class from your IDE (for example from SpringBoot launcher in IDEA)

Run the frontend

  1. Go to the frontend directory
  2. Run yarn install (needed only for the first run)
  3. Run yarn start

GraphiQL

After running the server, the GraphiQL API Explorer is available at http://localhost:9000/graphiql

GraphQL Features in this application

  • schema definition with SDL: rating.graphqls

  • Resolver for root fields (queries): RatingQueryResolver

  • Resolver for mutations: RatingMutationResolver

  • Using the Websocket Servlet for Subscriptions via Websocket: ExampleGraphQLConfiguration.serverEndpointRegistration (nearly the same as in the spring-boot-starter, only a little simplified for easier understanding)

  • Resolver for subscriptions (each new rating is pushed to clients): RatingSubscriptionResolver

  • Field resolver with arguments: ShopBeerResolver.ratingsWithStars (that should be in BeerFieldResolver but does not work due to graphl-java-tools bug: graphql-java-kickstart/graphql-java-tools#171)

  • Extending types and root fields in by a second schema (modulariation of schemas): see shop subproject:

    • shop.graphqls extends the basic schema from beerrating
    • ShopResolver adds a field resolver for the Beer type from beerrating (field shops)
    • ShopResolver.address adds a field resolver for the Shop type, as address (defined in the schema) does not exist on the Shop java class.
  • Security for mutations using Spring Security: RatingMutationResolver.addRating

Architecture

The project contains of two apps:

  • shopservice: A little "microservice", that knows a list of Shops and what Beer they sell. The shopservice provides a REST endpoint for requesting shops.

  • beeradivsor: the "real" application that provides Beer, Rating and the GraphQL API

The beeradivsor project is setup as a multi module gradle project that consists of three Gradle modules:

  • beerrating: this is our "core" domain. It consists of the Beer and Rating entities

  • shop: this is the GraphQL "gateway" to the shopservice

  • app: this contains all necessary infrastructure code and configuration. It also configures the GraphQL servlet.

Both of the "domain" modules ship their own GraphQL API (so they are complete verticals), while "beerrating" is the base API that is extended by the "shop" module with the shop-specific types and queries. One could use the beerrating API without the shop api.

The third module is the Spring Boot Application module:

graphql-spring-boot-starter vs custom configuration

For demonstration purposes that project by default does not use the graphiql-spring-boot-starter to configure the GraphQL schema and servlet.

Instead the configuration is manually done in ExampleGraphQLConfiguration inside the app module.

To use the starter project instead:

  1. remove the @Configuration annotation from ExampleGraphQLConfiguration
  2. add the starter module to the gradle dependencies (app/build.gradle): compile compile 'com.graphql-java:graphql-spring-boot-starter:4.2.0'