Comparing REST and GraphQL

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Translation of the article Sashko Stubailo GraphQL vs. REST

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Two ways to send data over HTTP: what's the difference?

GraphQL is often presented as a revolutionary new way of understanding API. Instead of working with endpoints fixed on the server, you can get exactly the data you need with one request. And yes - GraphQL is flexible when implemented in an organization; it makes collaboration between frontend and backend development teams as smooth as ever. However, in practice, both of these technologies involve sending an HTTP request and getting some result, and inside GraphQL there are a lot of elements from the REST model embedded.

So what is really the difference at the technical level? What are the similarities and differences between these two API paradigms? By the end of the article, I will show you that GraphQL and REST are not so different, but GraphQL has some minor differences that significantly change the process of building and using API by developers.

So let's go straight to the point. We define some API properties and then discuss how they are implemented in GraphQL and REST.

Resources

REST  — .   URL,   GET-   URL. ,   JSON,   API. :

GET /books/1

{
  "title": "      ",
  "author": { 
    "firstName": "",
    "lastName": ""
  }
  // ...  
}

: REST API   ( «author») .

  REST  , , ,   .      REST API,      «book endpoint».

GraphQL   ,  GraphQL  .   , Book Author:

type Book {
  id: ID
  title: String
  published: Date
  price: String
  author: Author
}

type Author {
  id: ID
  firstName: String
  lastName: String
  books: [Book]
}

:   ,      , .   REST  GraphQL :     .

  , Query   :

type Query {
  book(id: ID!): Book
  author(id: ID!): Author
}

  , REST-, ,      GraphQL:

GET /graphql?query={ book(id: "1") { title, author { firstName } } }

{
  "title": "      ",
  "author": {
    "firstName": "",
  }
}

, -!   GraphQL,  REST,  , URL,      JSON-.

,  ,  GraphQL- URL ,   . ,    ,   author, — , API.

, , , Books  Authors,      .            .

   :

• : , .
• :   GET- URL-  HTTP.
• :     JSON.
• :  REST (endpoint) —   .  GraphQL  ,   .
• :  REST   .  GraphQL ,    .

  GraphQL / REST, .    GraphQL,  Launchpad  , .

URL-   GraphQL

API ,  .   API,     - ,   ,       , .

,   API — ,   .  ,  ,  API,    GraphQL- REST API Swagger  .

  REST API API (endpoints):

GET /books/:id
GET /authors/:id
GET /books/:id/comments
POST /books/:id/comments


, «» API  — . - ,   : « endpoint »?

 GraphQL,   ,    URL- ,  API.   GraphQL-:

type Query {
  book(id: ID!): Book
  author(id: ID!): Author
}

type Mutation {
  addComment(input: AddCommentInput): Comment
}

type Book { ... }
type Author { ... }
type Comment { ... }
input AddCommentInput { ... }

    REST . : HTTP-    URL-   (GET, PUT, DELETE  ..) GraphQL    —  Mutation Query.  GraphQL-   ,  ,   :

query { ... }
mutation { ... }

  « GraphQL» (.), .

, Query   REST, . ,   ,  GraphQL «URL (endpoint URL)».

 GraphQL API  ,  REST:     ;    ,   .  GraphQL  , ,  ,   REST   ,   ,   -  URL- .

 REST (endpoints),   GraphQL    .

• :  REST API     Query Mutation,  GraphQL API.  .
• :  API     .
• :  GraphQL      , ,  .  REST   .
• :  GraphQL Query   ,   ,   query. ,     .  REST     URL.
• :  REST   , HTTP- GET  - POST.  GraphQL   .

-   , , Query « » «» GraphQL.   ,   , Query , ,    .

 

, ,   API? ,   - , . ,  , API,   , .  , , .    REST,   GraphQL API,     , .

     JavaScript,   ,  ,  ,  REST,  GraphQL API.   ,   ,   .

«Hello World»   express, API  Node:

app.get('/hello', function (req, res) {
  res.send('Hello World!')
})

,   /hello, 'Hello World!'.   HTTP-   REST API:

1.   HTTP- (  GET)   URL
2. API-    ,  
3.  
4. API- ,    

GraphQL ,       :

const resolvers = {
  Query: {
    hello: () => {
      return 'Hello world!';
    },
  },
};

, URL  , ,    — hello Query.  GraphQL , , (resolver).

, (query):

query {
  hello
}

, , GraphQL-:

1. HTTP-     GraphQL-
2. (query) ,   (resolver).   , hello,   Query.
3.  
4. GraphQL    , (query)

    :

{ "hello": "Hello, world!" }

  :   !

query {
  hello
  secondHello: hello
}

   ,        ( ), hello   . ,    ,   ,        .

     («nested» resolvers):

{
  Query: {
    author: (root, { id }) => find(authors, { id: id }),
  },
  Author: {
    posts: (author) => filter(posts, { authorId: author.id }),
  },
}

:

query {
  author(id: 1) {
    firstName
    posts {
      title
    }
  }
}

,   , -        .  , GraphQL,   «GraphQL Explained».

  , !

:  REST  ,  GraphQL -

  REST,  GraphQL API  . REST API, GraphQL API  . GraphQL :   .

• :  REST    GraphQL   .
• : REST,  GraphQL         .
• :  REST - .  GraphQL -   .
• :  REST   .  GraphQL , GraphQL, .

 ,    GraphQL     . REST.

?

,       . , , . ,   .  ,  ,   ,  , REST  GraphQL  , .

 ,     GraphQL.  , , API -,   ,   . API     ,   API ,  .

  , GraphQL    , REST. ,       HTTP- GraphQL API   , REST API.  ,   GraphQL  , Apollo Client  Relay.

    REST  GraphQL —  .