Code Using GraphQL

docker pull dgraph/standalone
mkdir -p ~/dgraph
docker run -it -p 5080:5080 -p 6080:6080 -p 8080:8080 \
  -p 9080:9080 -p 8000:8000 -v ~/dgraph:/dgraph --name dgraph \
  dgraph/standalone:master

touch schema.graphql
nano schema.graphql

type Product {
  id: ID!
  name: String! @id
  reviews: [Review] @hasInverse(field: about)
}
 
type Customer {
  username: String! @id
  reviews: [Review] @hasInverse(field: by)
}
 
type Review {
  id: ID!
  about: Product!
  by: Customer!
  comment: String @search(by: [fulltext])
  rating: Int @search
}

curl -X POST localhost:8080/admin/schema --data-binary '@schema.graphql'

mutation {
  addProduct(input: [{ name: "Dgraph" }, { name: "Dgraph Cloud" }]) {
    product {
      id
      name
    }
  }
  addCustomer(input: [{ username: "TonyStark" }]) {
    customer {
      username
    }
  }
}

mutation {
  addReview(
    input: [
      {
        by: { username: "TonyStark" }
        about: { name: "Dgraph" }
        comment: "Fantastic, easy to install, worked great. Best GraphQL server available"
        rating: 10
      }
    ]
  ) {
    review {
      id
      comment
      rating
      by {
        username
      }
      about {
        id
        name
      }
    }
  }
}

query {
  queryReview(
    filter: { comment: { alloftext: "server easy install" }, rating: { gt: 5 } }
  ) {
    comment
    by {
      username
      reviews(order: { desc: rating }, first: 10) {
        about {
          name
          reviews(order: { asc: rating }, first: 5) {
            by {
              username
            }
            comment
            rating
          }
        }
        rating
      }
    }
    about {
      name
    }
  }
}

import ballerina/graphql;
import ballerina/io;
 
type Response record {
    record { string hello; } data;
};
 
public function main() returns error? {
    graphql:Client helloClient = check new ("localhost:9090/graphql");
    string document = "{ hello }";
    Response response = check helloClient->execute(document);
    io:println(response.data.hello);
}

import ballerina/graphql;
 
service /graphql on new graphql:Listener(9090) {
    resource function get hello() returns string {
        return "Hello, world!";
    }
}

var orders = await sampleClient
    .Query
        .Orders(first: 10)
        .Include(e => e.Orders.Select(e => e.Customer))
        .Select(e => e.Orders)
        .ExecuteAsync();

 var customerId = await sampleClient
     .Mutation
     .AddCustomer(new CustomerInput
     {
         CustomerId = Guid.NewGuid(),
         CustomerName = "New Customer",
         Status = CustomerStatus.Active
     })
     .Select(e=> e.CustomerId)
     .ExecuteAsync();

client.GetHero
    .Watch(ExecutionStrategy.CacheFirst)
    .Subscribe(result =>
    {
        Console.WriteLine(result.Data.Name);
    })

var userId = 10;
var response = await qlClient.Query(q => q
    .User(userId, o => new
    {
        o.Id,
        o.FirstName,
        o.LastName
    }));

// expose an existing data model with ASP.NET & EF Core
public class Startup {
  public void ConfigureServices(IServiceCollection services)
  {
      services.AddDbContext<DemoContext>();
      // Auto build a schema from DemoContext. Alternatively you can build one from scratch
      services.AddGraphQLSchema<DemoContext>(options =>
      {
          // modify the schema (add/remove fields or types), add other services
      });
  }
 
  public void Configure(IApplicationBuilder app, DemoContext db)
  {
      app.UseRouting();
      app.UseEndpoints(endpoints =>
      {
          // defaults to /graphql endpoint
          endpoints.MapGraphQL<DemoContext>();
      });
  }
}

using System;
using System.Threading.Tasks;
using GraphQL;
using GraphQL.Types;
using GraphQL.SystemTextJson; // First add PackageReference to GraphQL.SystemTextJson
 
public class Program
{
  public static async Task Main(string[] args)
  {
    var schema = Schema.For(@"
      type Query {
        hello: String
      }
    ");
 
    var json = await schema.ExecuteAsync(_ =>
    {
      _.Query = "{ hello }";
      _.Root = new { Hello = "Hello World!" };
    });
 
    Console.WriteLine(json);
  }
}

using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;
 
WebHost
    .CreateDefaultBuilder(args)
    .ConfigureServices(services =>
        services
            .AddGraphQLServer()
            .AddQueryType<Query>())
    .Configure(builder =>
        builder
            .UseRouting()
            .UseEndpoints(e => e.MapGraphQL()))
    .Build()
    .Run();
 
public class Query
{
    public Hero GetHero() => new Hero();
}
 
public class Hero
{
    public string Name => "Luke Skywalker";
}

(require '[alumbra.core :as alumbra]
         '[claro.data :as data])
 
(def schema
  "type Person { name: String!, friends: [Person!]! }
   type QueryRoot { person(id: ID!): Person, me: Person! }
   schema { query: QueryRoot }")
 
(defrecord Person [id]
  data/Resolvable
  (resolve! [_ _]
    {:name    (str "Person #" id)
     :friends (map ->Person  (range (inc id) (+ id 3)))}))
 
(def QueryRoot
  {:person (map->Person {})
   :me     (map->Person {:id 0})})
 
(def app
  (alumbra/handler
    {:schema schema
     :query  QueryRoot}))
 
(defonce my-graphql-server
  (aleph.http/start-server #'app {:port 3000}))

$ curl -XPOST "http://0:3000" -H'Content-Type: application/json' -d'{
  "query": "{ me { name, friends { name } } }"
}'
{"data":{"me":{"name":"Person #0","friends":[{"name":"Person #1"},{"name":"Person #2"}]}}}

(def schema "type QueryRoot {
    hello: String
  }")
 
(defn resolver-fn [type-name field-name]
  (get-in {"QueryRoot" {"hello" (fn [context parent & rest]
                              "Hello world!")}}
          [type-name field-name]))
 
(require '[graphql-clj.executor :as executor])
 
(executor/execute nil schema resolver-fn "{ hello }")

package main

import "github.com/andrewwphillips/eggql"

func main() {
	http.Handle("/graphql", eggql.New(struct{ Message string }{Message: "hello, world"}))
	http.ListenAndServe(":80", nil)
}

$ curl -XPOST -d '{"query": "{ message }"}' localhost:80/graphql

{
  "data": {
    "message": "hello, world"
  }
}

# schema.gql
"""
A supernatural being considered divine and sacred
"""
type Deity {
  name: String!
  power: String @deprecated(reason: "no more supported")
}
type Query {
  deity(name: String! = "Morpheus"): Deity!
}

{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DuplicateRecordFields #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeFamilies #-}
module API (api) where
import Data.ByteString.Lazy.Char8 (ByteString)
import Data.Morpheus (interpreter)
import Data.Morpheus.Document (importGQLDocument)
import Data.Morpheus.Types (RootResolver (..), Undefined (..))
import Data.Text (Text)
importGQLDocument "schema.gql"
rootResolver :: RootResolver IO () Query Undefined Undefined
rootResolver =
  RootResolver
    { queryResolver = Query {deity},
      mutationResolver = Undefined,
      subscriptionResolver = Undefined
    }
  where
    deity DeityArgs {name} =
      pure
        Deity
          { name = pure name,
            power = pure (Just "Shapeshifting")
          }
api :: ByteString -> IO ByteString
api = interpreter rootResolver

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
 
-- imports omitted for brevity...
 
graphql "Library" "library.graphql" -- all the magic happens here! 🪄🎩
 
-- ... a bit more code...
 
libraryServer :: SqlBackend -> ServerT ObjectMapping i Library ServerErrorIO _
libraryServer conn =
  resolver
    ( object @"Book"
        ( field @"id" bookId,
          field @"title" bookTitle,
          field @"author" bookAuthor,
          field @"imageUrl" bookImage
        ),
      object @"Author"
        ( field @"id" authorId,
          field @"name" authorName,
          field @"books" authorBooks
        ),
      object @"Query"
        ( method @"authors" allAuthors,
          method @"books" allBooks
        ),
      object @"Mutation"
        ( method @"newAuthor" newAuthor,
          method @"newBook" newBook
        ),
      object @"Subscription"
        (method @"allBooks" allBooksConduit)
    )
  where
    bookId :: Entity Book -> ServerErrorIO Integer
    bookId (Entity (BookKey k) _) = pure $ toInteger k
    -- ... more resolvers...

// build.gradle.kts
import com.expediagroup.graphql.plugin.gradle.graphql
 
plugins {
    id("com.expediagroup.graphql") version $latestGraphQLKotlinVersion
}
 
dependencies {
  implementation("com.expediagroup:graphql-kotlin-spring-client:$latestGraphQLKotlinVersion")
}
 
graphql {
    client {
        // target GraphQL endpoint
        endpoint = "http://localhost:8080/graphql"
        // package for generated client code
        packageName = "com.example.generated"
    }
}

query HelloWorldQuery {
  helloWorld
}

package com.example.generated
 
import com.expediagroup.graphql.client.types.GraphQLClientRequest
import kotlin.String
import kotlin.reflect.KClass
 
const val HELLO_WORLD_QUERY: String = "query HelloWorldQuery {\n    helloWorld\n}"
 
class HelloWorldQuery: GraphQLClientRequest<HelloWorldQuery.Result> {
    override val query: String = HELLO_WORLD_QUERY
 
    override val operationName: String = "HelloWorldQuery"
 
    override fun responseType(): KClass<HelloWorldQuery.Result> = HelloWorldQuery.Result::class
 
    data class Result(
        val helloWorld: String
    }
}

package com.example.client
 
import com.expediagroup.graphql.client.spring.GraphQLWebClient
import com.expediagroup.graphql.generated.HelloWorldQuery
import kotlinx.coroutines.runBlocking
 
fun main() {
    val client = GraphQLWebClient(url = "http://localhost:8080/graphql")
    runBlocking {
        val helloWorldQuery = HelloWorldQuery()
        val result = client.execute(helloWorldQuery)
        println("hello world query result: ${result.data?.helloWorld}")
    }
}

query basicMapValue($userIds: [Int]) {
  userInfoList(userIds: $userIds) {
    id
    age
    firstName
    lastName
    fullName: stringHolder @map(mapper: "firstName + lastName")
  }
}
 
query filterUserByAge($userId: [Int]) {
  userInfoList(userIds: $userId) @filter(predicate: "age>=18") {
    userId
    age
    firstName
    lastName
  }
}
 
query parseFetchedValueToAnotherFieldArgumentMap($itemIds: [Int]) {
  itemList(itemIds: $itemIds) {
    # save sellerId as List<Long> with unique name "sellerIdList"
    sellerId @fetchSource(name: "sellerIdList")
    name
    saleAmount
    salePrice
  }
 
  userInfoList(userIds: 1)
    # transform the argument of "userInfoList" named "userIds" according to expression "sellerIdList" and expression argument,
    # which mean replace userIds value by source named "sellerIdList"
    @argumentTransform(
      argumentName: "userIds"
      operateType: MAP
      expression: "sellerIdList"
      dependencySources: ["sellerIdList"]
    ) {
    userId
    name
    age
  }
}

import graphql.ExecutionResult;
import graphql.GraphQL;
import graphql.schema.GraphQLSchema;
import graphql.schema.StaticDataFetcher;
import graphql.schema.idl.RuntimeWiring;
import graphql.schema.idl.SchemaGenerator;
import graphql.schema.idl.SchemaParser;
import graphql.schema.idl.TypeDefinitionRegistry;
 
import static graphql.schema.idl.RuntimeWiring.newRuntimeWiring;
 
public class HelloWorld {
 
    public static void main(String[] args) {
        String schema = "type Query{hello: String}";
 
        SchemaParser schemaParser = new SchemaParser();
        TypeDefinitionRegistry typeDefinitionRegistry = schemaParser.parse(schema);
 
        RuntimeWiring runtimeWiring = newRuntimeWiring()
                .type("Query", builder -> builder.dataFetcher("hello", new StaticDataFetcher("world")))
                .build();
 
        SchemaGenerator schemaGenerator = new SchemaGenerator();
        GraphQLSchema graphQLSchema = schemaGenerator.makeExecutableSchema(typeDefinitionRegistry, runtimeWiring);
 
        GraphQL build = GraphQL.newGraphQL(graphQLSchema).build();
        ExecutionResult executionResult = build.execute("{hello}");
 
        System.out.println(executionResult.getData().toString());
        // Prints: {hello=world}
    }
}

// build.gradle.kts
implementation("com.expediagroup", "graphql-kotlin-spring-server", latestVersion)

graphql:
  packages:
    - "com.your.package"

@Component
class HelloWorldQuery : Query {
  fun helloWorld() = "Hello World!!!"
}

type Query {
  helloWorld: String!
}

data class Article(val id: Int, val text: String)
 
fun main() {
    val schema = KGraphQL.schema {
        query("article") {
            resolver { id: Int?, text: String ->
                Article(id ?: -1, text)
            }
        }
        type<Article> {
            property<String>("fullText") {
                resolver { article: Article ->
                    "${article.id}: ${article.text}"
                }
            }
        }
    }
 
    schema.execute("""
        {
            article(id: 5, text: "Hello World") {
                id
                fullText
            }
        }
    """).let(::println)
}

fun Application.module() {
  install(GraphQL) {
    playground = true
    schema {
      query("hello") {
        resolver { -> "World!" }
      }
    }
  }
}

@Controller
public class GreetingController {
 
    @QueryMapping
    public String hello() {
        return "Hello, world!";
    }
 
}