HTTP

Data

data.json

{  "1": {    "id": "1",    "name": "Dan"  },  "2": {    "id": "2",    "name": "Lee"  },  "3": {    "id": "3",    "name": "Nick"  }}

Main

main.go

package main
import (    "encoding/json"    "fmt"    "io/ioutil"    "net/http"
    "github.com/graphql-go/graphql")
type user struct {    ID   string `json:"id"`    Name string `json:"name"`}
var data map[string]user
/*   Create User object type with fields "id" and "name" by using GraphQLObjectTypeConfig:       - Name: name of object type       - Fields: a map of fields by using GraphQLFields   Setup type of field use GraphQLFieldConfig*/var userType = graphql.NewObject(    graphql.ObjectConfig{        Name: "User",        Fields: graphql.Fields{            "id": &graphql.Field{                Type: graphql.String,            },            "name": &graphql.Field{                Type: graphql.String,            },        },    },)
/*   Create Query object type with fields "user" has type [userType] by using GraphQLObjectTypeConfig:       - Name: name of object type       - Fields: a map of fields by using GraphQLFields   Setup type of field use GraphQLFieldConfig to define:       - Type: type of field       - Args: arguments to query with current field       - Resolve: function to query data using params from [Args] and return value with current type*/var queryType = graphql.NewObject(    graphql.ObjectConfig{        Name: "Query",        Fields: graphql.Fields{            "user": &graphql.Field{                Type: userType,                Args: graphql.FieldConfigArgument{                    "id": &graphql.ArgumentConfig{                        Type: graphql.String,                    },                },                Resolve: func(p graphql.ResolveParams) (interface{}, error) {                    idQuery, isOK := p.Args["id"].(string)                    if isOK {                        return data[idQuery], nil                    }                    return nil, nil                },            },        },    })
var schema, _ = graphql.NewSchema(    graphql.SchemaConfig{        Query: queryType,    },)
func executeQuery(query string, schema graphql.Schema) *graphql.Result {    result := graphql.Do(graphql.Params{        Schema:        schema,        RequestString: query,    })    if len(result.Errors) > 0 {        fmt.Printf("wrong result, unexpected errors: %v", result.Errors)    }    return result}
func main() {    _ = importJSONDataFromFile("data.json", &data)
    http.HandleFunc("/graphql", func(w http.ResponseWriter, r *http.Request) {        result := executeQuery(r.URL.Query().Get("query"), schema)        json.NewEncoder(w).Encode(result)    })
    fmt.Println("Now server is running on port 8080")    fmt.Println("Test with Get      : curl -g 'http://localhost:8080/graphql?query={user(id:\"1\"){name}}'")    http.ListenAndServe(":8080", nil)}
//Helper function to import json from file to mapfunc importJSONDataFromFile(fileName string, result interface{}) (isOK bool) {    isOK = true    content, err := ioutil.ReadFile(fileName)    if err != nil {        fmt.Print("Error:", err)        isOK = false    }    err = json.Unmarshal(content, result)    if err != nil {        isOK = false        fmt.Print("Error:", err)    }    return}