vinod-mishra / Spring-GraphQL-API

Demo Project Book API

Intro

Demo POC project for GraphQl + Spring Boot. The project uses graphql to create a simple book and author schema to demonstrate the use of GraphQl Query, Mutation functionality.

Requirements

• Java 11
• Basic Knowledge of GraphQl and Spring boot
• Intellij or IDE of your choice
• Postman for testing the API

What is GraphQl?

GraphQl is a query language that can be used to develop APIs which uses a different approach than the trditional REST APIs. Unlike traditional REST APIs GraphQl allows the client to specify which data required and thus allowing multiple queries in a single request. This helps to develop light weight manageable APIs.

Official documentation: GraphQL

How to execute

To run the project and execute queries follow below steps:

• maven clean build

mvn clean build

• In terminal cd the Root folder of project where we have docker-compose.yml

docker-compose up -d

• the endpoint exposed at : localhost
• postman or any Http client can be used to test the graphql queries

To stop all containers

docker-compose down

Example of some queries/mutations:

Note all queries and mutations in GraphQl are post Http requests.

Why only Post?

Well, there are few reasons:

• GraphQl itself is transport-agnostic, it's not specific to HTTP. A GraphQl service can execute documents outside the context of network requests.
• There is no body in a GET request, which means the query, variables and operation name all have to be set through query parameters which can easily cause server to return 414 status(URI too long)

Query example

get all books

 query {
 allBook{
   id
   name
   pageCount
 }
 }

get book with author

   query {
   allBook{
        id
       name
       pageCount
       author{
         id
         firstName
         lastName
  
       }
   }
   }

The output of this request is as follows:

• Mutation example

create new book

  mutation {
  newBook(name:"Scrum Master", pageCount:"250"){
    id
    name
    pageCount
  }
  }

delete book

  mutation {
  deleteBook(id:3){
    id
    name
    pageCount
  }
  }

Response: