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Querying a GraphQL API Implementation

The following examples illustrate the implementation of a GraphQL service to query data using APIkit for GraphQL.

Before running these examples, download and run the APIkit for GraphQL application example, which loads a sample dataset in memory for testing purposes. Get more information about the format of the queries sent through an HTTP POST request.

The example application is based on the following GraphQL API:

type Post {
    id: ID!
    user: User
    title: String
    body: String
    comments: [Comment]
}

type Comment {
    id: ID!
    user: User
    post: Post
    body: String
    replies: [Comment]
}

type User {
    id: ID!
    name: String
    username: String
    email: String
    phone: String
    website: String
    address: Address
}

type Address {
    id: ID!
    street: String
    city: String
    zipcode: String
    latitude: Float
    longitude: Float
}

input AddressInput {
    street: String
    city: String
    zipcode: String
    latitude: Float
    longitude: Float
}

input UserInput {
    name: String
    username: String
    email: String
    phone: String
    website: String
    address: AddressInput
}

type Query {
    # Looks for a user by ID
    getUser(id: ID!): User
    # Looks for a post by ID
    getPost(id: ID!): Post
    # Returns the list of all users
    allUsers: [User]
    # Returns the list of all posts
    allPosts: [Post]
}

type Mutation {
    # Creates a new user
    createUser(user: UserInput!): User!
    # Creates a new post
    createPost(userId: ID!, title: String!, body: String!): Post!
    # Adds a comment to a post
    postComment(userId: ID!, postId: ID!, body: String!): Comment!
    # Adds a reply to a comment
    replyToComment(commentId: ID!, userId: ID!, body: String!): Comment!
}

Request Queries Examples

In the following example, the type Query defines the list of queries that the service exposes:

...
type Query {
    # Looks for a user by ID
    getUser(id: ID!): User
    # Looks for a post by ID
    getPost(id: ID!): Post
    # Returns the list of all users
    allUsers: [User]
    # Returns the list of all posts
    allPosts: [Post]
}
...

Retrieve All Posts

This use case makes a simple request for the data of each existing post:

Make a Query

{
   allPosts {
       id
       title
       body
   }
}

Trigger a Request

curl --location --request POST 'http://localhost:8081/graphql' \
--header 'Content-Type: application/json' \
--data-raw '{"query":"{allPosts{id title body}}","variables":{}}'

Get a Response

{
   "data": {
       "allPosts": [
           {
               "id": "88",
               "title": "tellus nisi eu orci mauris lacinia sapien quis libero",
               "body": "Praesent id massa id nisl venenatis lacinia. Aenean sit amet justo. Morbi ut odio. Cras mi pede, malesuada in, imperdiet et, commodo vulputate, justo. In blandit ultrices enim. Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin interdum mauris non ligula pellentesque ultrices. Phasellus id sapien in sapien iaculis congue. Vivamus metus arcu, adipiscing molestie, hendrerit at, vulputate vitae, nisl."
           },
           {
               "id": "89",
               "title": "mauris lacinia sapien quis libero",
               "body": "Sed ante. Vivamus tortor. Duis mattis egestas metus. Aenean fermentum. Donec ut mauris eget massa tempor convallis. Nulla neque libero, convallis eget, eleifend luctus, ultricies eu, nibh. Quisque id justo sit amet sapien dignissim vestibulum. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Nulla dapibus dolor vel est. Donec odio justo, sollicitudin ut, suscipit a, feugiat et, eros."
           },
           ...
           {
            "id": "87",
               "title": "nam tristique",
               "body": "Proin eu mi. Nulla ac enim. In tempor, turpis nec euismod scelerisque, quam turpis adipiscing lorem, vitae mattis nibh ligula nec sem. Duis aliquam convallis nunc. Proin at turpis a pede posuere nonummy. Integer non velit. Donec diam neque, vestibulum eget, vulputate ut, ultrices vel, augue. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Donec pharetra, magna vestibulum aliquet ultrices, erat tortor sollicitudin mi, sit amet lobortis sapien sapien non mi. Integer ac neque."
           }
       ]
   }
}

Retrieve All Users with Data Loader

This query requests the data of all users, including their address information. This example uses a Data Loader to fetch the addresses of each user with one request.

Make a Query

{
   allUsers {
       name
       email
       website
       address {
           street
           city
           zipcode
       }
   }
}

Trigger a Request

curl --location --request POST 'http://localhost:8081/graphql' \
--header 'Content-Type: application/json' \
--data-raw '{"query":"{allUsers{name email website address{street city zipcode}}}","variables":{}}'

Get a Response

{
   "data": {
       "allUsers": [
           {
               "name": "Rollin Sebley",
               "email": "rsebley2f@ucsd.edu",
               "website": "homestead.com",
               "address": {
                   "street": "432 Myrtle Trail",
                   "city": "Pau",
                   "zipcode": "64029 CEDEX 9"
               }
           },
           {
               "name": "Bonny Madgewick",
               "email": "bmadgewick2g@mozilla.com",
               "website": "utexas.edu",
               "address": {
                   "street": "5 David Terrace",
                   "city": "Oelaba",
                   "zipcode": null
               }
           },
           ...
           {
               "name": "Gretal Titmuss",
               "email": "gtitmuss2e@soup.io",
               "website": "creativecommons.org",
               "address": {
                   "street": "3201 Gale Place",
                   "city": "Bolo",
                   "zipcode": "4201"
               }
           }
       ]
   }
}

Retrieve a Post by ID

This query example requests the post data by its ID, including the post comments and the usernames.

Make a Query

{
   getPost(id: 10) {
       id
       user {
           username
       }
       title
       body
       comments {
           user {
               username
           }
           body
           replies {
               body
           }
       }
   }
}

Trigger a Request

curl --location --request POST 'http://localhost:8081/graphql' \
--header 'Content-Type: application/json' \
--data-raw '{"query":"{getPost(id:10){id user{username}title body comments{user{username}body replies{body}}}}","variables":{}}'

Get a Response

{
   "data": {
       "getPost": {
           "id": "10",
           "user": {
               "username": "bdearelli"
           },
           "title": "id luctus nec molestie sed justo pellentesque viverra pede ac",
           "body": "Maecenas tristique, est et tempus semper, est quam pharetra magna, ac consequat metus sapien ut nunc. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Mauris viverra diam vitae quam. Suspendisse potenti. Nullam porttitor lacus at turpis. Donec posuere metus vitae ipsum. Aliquam non mauris.",
           "comments": [
               {
                   "user": {
                       "username": "cwalesby1p"
                   },
                   "body": "Praesent blandit. Nam nulla. Integer pede justo, lacinia eget, tincidunt eget, tempus vel, pede. Morbi porttitor lorem id ligula. Suspendisse ornare consequat lectus. In est risus, auctor sed, tristique in, tempus sit amet, sem.",
                   "replies": []
               },
               {
                   "user": {
                       "username": "rricci2d"
                   },
                   "body": "Maecenas leo odio, condimentum id, luctus nec, molestie sed, justo. Pellentesque viverra pede ac diam. Cras pellentesque volutpat dui.",
                   "replies": []
               }
           ]
       }
   }
}

Request Mutations Examples

The Mutation type defines the list of mutations that the service enables.

...
type Mutation {
    # Creates a new user
    createUser(user: UserInput!): User!
    # Creates a new post
    createPost(userId: ID!, title: String!, body: String!): Post!
    # Adds a comment to a post
    postComment(userId: ID!, postId: ID!, body: String!): Comment!
    # Adds a reply to a comment
    replyToComment(commentId: ID!, userId: ID!, body: String!): Comment!
}
...

Create a New Post

This example request creates a new post and asks for some information about it.

Make a Query

mutation CreatePost($userId: ID!, $title: String!, $body: String!) {
   createPost(userId: $userId,title: $title,body: $body) {
       id
       user {
           username
       }
       title
       body
       comments {
           body
       }
   }
}

Make a Variable

{
   "userId": 42,
   "title": "GraphQL by example",
   "body": "Let's talk about GraphQL"
}

Trigger a Request

curl --location --request POST 'http://localhost:8081/graphql' \
--header 'Content-Type: application/json' \
--data-raw '{"query":"mutation CreatePost($userId:ID!,$title:String!,$body:String!){createPost(userId:$userId,title:$title,body:$body){id user{username}title body comments{body}}}","variables":{"userId":42,"title":"GraphQL by example","body":"Let'\''s talk about GraphQL"}}'

Get a Response

{
   "data": {
       "createPost": {
           "id": "101",
           "user": {
               "username": "tblackmore15"
           },
           "title": "GraphQL by example",
           "body": "Let's talk about GraphQL",
           "comments": []
       }
   }
}

Add a Comment to the New Post

This example posts a comment in a reply to the post created in the previous step. It also asks for the service to return the body of the comment created and the original post with its list of comments to check that the new one is included.

Make a Query

mutation PostComment($userId: ID!, $postId: ID!, $body: String!) {
   postComment(userId: $userId, postId: $postId, body: $body) {
       id
       body
       post {
           id
           title
           comments {
               id
               user {
                   username
               }
               body
           }
       }
   }
}

Make a Variable

{
   "userId": 34,
   "postId": 101,
   "body": "Nice post! Thanks for sharing! It's just what I was looking for"
}

Trigger a Request

curl --location --request POST 'http://localhost:8081/graphql' \
--header 'Content-Type: application/json' \
--data-raw '{"query":"mutation PostComment($userId:ID!,$postId:ID!,$body:String!){postComment(userId:$userId,postId:$postId,body:$body){id body post{id title comments{id user{username}body}}}}","variables":{"userId":34,"postId":101,"body":"Nice post! Thanks for sharing! It'\''s just what I was looking for"}}'

Get a Response

{
   "data": {
       "postComment": {
           "id": "201",
           "body": "Nice post! Thanks for sharing! It's just what I was looking for",
           "post": {
               "id": "101",
               "title": "GraphQL by example",
               "comments": [
                   {
                       "id": "201",
                       "user": {
                           "username": "ekosex"
                       },
                       "body": "Nice post! Thanks for sharing! It's just what I was looking for"
                   }
               ]
           }
       }
   }
}

Reply to the New Comment in the Post

This request example creates a reply in response to the comment posted in the previous step. The query asks the service to return all the information of the post in addition to the new reply.

Make a Query

mutation ReplyToComment($commentId: ID!, $userId: ID!, $body: String!) {
   replyToComment(commentId: $commentId, userId: $userId, body: $body) {
       id
       body
       post {
           id
           title
           comments {
               id
               body
               replies {
                   id
                   user {
                       username
                   }
                   body
               }
           }
       }
   }
}

Make a Variable

{
   "commentId": 201,
   "userId": 42,
   "body": "Thank you!"
}

Trigger a Request

curl --location --request POST 'http://localhost:8081/graphql' \
--header 'Content-Type: application/json' \
--data-raw '{"query":"mutation ReplyToComment($commentId:ID!,$userId:ID!,$body:String!){replyToComment(commentId:$commentId,userId:$userId,body:$body){id body post{id title comments{id body replies{id user{username}body}}}}}","variables":{"commentId":201,"userId":42,"body":"Thank you!"}}'

Get a Response

{
   "data": {
       "replyToComment": {
           "id": "202",
           "body": "Thank you!",
           "post": {
               "id": "101",
               "title": "GraphQL by example",
               "comments": [
                   {
                       "id": "201",
                       "body": "Nice post! Thanks for sharing! It's just what I was looking for",
                       "replies": [
                           {
                               "id": "202",
                               "user": {
                                   "username": "tblackmore15"
                               },
                               "body": "Thank you!"
                           }
                       ]
                   }
               ]
           }
       }
   }
}