GraphQL

package main
 
import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
 
	"github.com/graphql-go/graphql"
)
 
type User struct {
	ID   int    `json:"id"`
	Name string `json:"name"`
}
 
var userType = graphql.NewObject(
	graphql.ObjectConfig{
		Name: "User",
		Fields: graphql.Fields{
			"id": &graphql.Field{
				Type: graphql.Int,
			},
			"name": &graphql.Field{
				Type: graphql.String,
			},
		},
	},
)
 
var queryType = graphql.NewObject(
	graphql.ObjectConfig{
		Name: "Query",
		Fields: graphql.Fields{
			"user": &graphql.Field{
				Type: userType,
				Args: graphql.FieldConfigArgument{
					"id": &graphql.ArgumentConfig{
						Type: graphql.Int,
					},
				},
				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
					id, ok := p.Args["id"].(int)
					if ok {
						if id == 1 {
							return User{ID: 1, Name: "Alice"}, nil
						} else if id == 2 {
							return User{ID: 2, Name: "Bob"}, 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("Unexpected errors inside ExecuteQuery: %v", result.Errors)
	}
	return result
}
 
func main() {
	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 8088")
	fmt.Println("Test with Get      : curl -g 'http://localhost:8088/graphql?query={user(id:1){name}}'")
	fmt.Println("Test with Post method: curl -XPOST -H 'Content-Type: application/json' -d '{\"query\": \"{user(id:2){id name}}\"}' http://localhost:8088/graphql ")
	log.Fatal(http.ListenAndServe(":8088", nil))
}
 

curl -g 'http://localhost:8088/graphql?query={user(id:1){name}}'

D08042 :: ~ % curl -g 'http://localhost:8088/graphql?query={user(id:1){name}}'
{"data":{"user":{"name":"Alice"}}}

CheverJohn :: ~ % curl -s -g 'http://localhost:8088/graphql?query={user(id:1){name}}' | jq '.'
{
  "data": {
    "user": {
      "name": "Alice"
    }
  }
}
CheverJohn :: ~ % curl -s --show-error -g 'http://localhost:8088/graphql?query={user(id:1){name}}' | jq '.'
{
  "data": {
    "user": {
      "name": "Alice"
    }
  }
}

package main
 
import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"strconv"
)
 
type User struct {
	ID   int    `json:"id"`
	Name string `json:"name"`
}
 
var users = []User{
	{ID: 1, Name: "Alice"},
	{ID: 2, Name: "Bob"},
}
 
func getUser(id int) (*User, error) {
	for _, user := range users {
		if user.ID == id {
			return &user, nil
		}
	}
	return nil, fmt.Errorf("user with ID %d not found", id)
}
 
func userHandler(w http.ResponseWriter, r *http.Request) {
	idStr := r.URL.Path[len("/users/"):]
	id, err := strconv.Atoi(idStr)
	if err != nil {
		http.Error(w, "Invalid user ID", http.StatusBadRequest)
		return
	}
 
	user, err := getUser(id)
	if err != nil {
		http.Error(w, err.Error(), http.StatusNotFound)
		return
	}
 
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(user)
}
 
func main() {
	http.HandleFunc("/users/", userHandler) // Handles requests like /users/1, /users/2, etc.
 
	fmt.Println("Now server is running on port 8088")
	fmt.Println("Test with Get: curl http://localhost:8088/users/1")
	log.Fatal(http.ListenAndServe(":8088", nil))
}

CheverJohn :: ~ % curl -s -g http://localhost:8088/users/1 | jq '.'
{
  "id": 1,
  "name": "Alice"
}