Go GraphQL CRUD Example
Implement create, read, update and delete on Go.
To run the program:
- go to the directory:
cd examples/crud - Run the example:
go run main.go
Create#
http://localhost:8080/product?query=mutation+_{create(name:"Inca Kola",info:"Inca Kola is a soft drink that was created in Peru in 1935 by British immigrant Joseph Robinson Lindley using lemon verbena (wiki)",price:1.99){id,name,info,price}}Read#
- Get single product by id:
http://localhost:8080/product?query={product(id:1){name,info,price}}- Get product list:
http://localhost:8080/product?query={list{id,name,info,price}}Update#
http://localhost:8080/product?query=mutation+_{update(id:1,price:3.95){id,name,info,price}}Delete#
http://localhost:8080/product?query=mutation+_{delete(id:1){id,name,info,price}}CRUD Example#
main.go
package main
import ( "encoding/json" "fmt" "math/rand" "net/http" "time"
"github.com/graphql-go/graphql")
// Product contains information about one producttype Product struct { ID int64 `json:"id"` Name string `json:"name"` Info string `json:"info,omitempty"` Price float64 `json:"price"`}
var products = []Product{ { ID: 1, Name: "Chicha Morada", Info: "Chicha morada is a beverage originated in the Andean regions of Perú but is actually consumed at a national level (wiki)", Price: 7.99, }, { ID: 2, Name: "Chicha de jora", Info: "Chicha de jora is a corn beer chicha prepared by germinating maize, extracting the malt sugars, boiling the wort, and fermenting it in large vessels (traditionally huge earthenware vats) for several days (wiki)", Price: 5.95, }, { ID: 3, Name: "Pisco", Info: "Pisco is a colorless or yellowish-to-amber colored brandy produced in winemaking regions of Peru and Chile (wiki)", Price: 9.95, },}
var productType = graphql.NewObject( graphql.ObjectConfig{ Name: "Product", Fields: graphql.Fields{ "id": &graphql.Field{ Type: graphql.Int, }, "name": &graphql.Field{ Type: graphql.String, }, "info": &graphql.Field{ Type: graphql.String, }, "price": &graphql.Field{ Type: graphql.Float, }, }, },)
var queryType = graphql.NewObject( graphql.ObjectConfig{ Name: "Query", Fields: graphql.Fields{ /* Get (read) single product by id http://localhost:8080/product?query={product(id:1){name,info,price}} */ "product": &graphql.Field{ Type: productType, Description: "Get product by id", Args: graphql.FieldConfigArgument{ "id": &graphql.ArgumentConfig{ Type: graphql.Int, }, }, Resolve: func(p graphql.ResolveParams) (interface{}, error) { id, ok := p.Args["id"].(int) if ok { // Find product for _, product := range products { if int(product.ID) == id { return product, nil } } } return nil, nil }, }, /* Get (read) product list http://localhost:8080/product?query={list{id,name,info,price}} */ "list": &graphql.Field{ Type: graphql.NewList(productType), Description: "Get product list", Resolve: func(params graphql.ResolveParams) (interface{}, error) { return products, nil }, }, }, })
var mutationType = graphql.NewObject(graphql.ObjectConfig{ Name: "Mutation", Fields: graphql.Fields{ /* Create new product item http://localhost:8080/product?query=mutation+_{create(name:"Inca Kola",info:"Inca Kola is a soft drink that was created in Peru in 1935 by British immigrant Joseph Robinson Lindley using lemon verbena (wiki)",price:1.99){id,name,info,price}} */ "create": &graphql.Field{ Type: productType, Description: "Create new product", Args: graphql.FieldConfigArgument{ "name": &graphql.ArgumentConfig{ Type: graphql.NewNonNull(graphql.String), }, "info": &graphql.ArgumentConfig{ Type: graphql.String, }, "price": &graphql.ArgumentConfig{ Type: graphql.NewNonNull(graphql.Float), }, }, Resolve: func(params graphql.ResolveParams) (interface{}, error) { rand.Seed(time.Now().UnixNano()) product := Product{ ID: int64(rand.Intn(100000)), // generate random ID Name: params.Args["name"].(string), Info: params.Args["info"].(string), Price: params.Args["price"].(float64), } products = append(products, product) return product, nil }, },
/* Update product by id http://localhost:8080/product?query=mutation+_{update(id:1,price:3.95){id,name,info,price}} */ "update": &graphql.Field{ Type: productType, Description: "Update product by id", Args: graphql.FieldConfigArgument{ "id": &graphql.ArgumentConfig{ Type: graphql.NewNonNull(graphql.Int), }, "name": &graphql.ArgumentConfig{ Type: graphql.String, }, "info": &graphql.ArgumentConfig{ Type: graphql.String, }, "price": &graphql.ArgumentConfig{ Type: graphql.Float, }, }, Resolve: func(params graphql.ResolveParams) (interface{}, error) { id, _ := params.Args["id"].(int) name, nameOk := params.Args["name"].(string) info, infoOk := params.Args["info"].(string) price, priceOk := params.Args["price"].(float64) product := Product{} for i, p := range products { if int64(id) == p.ID { if nameOk { products[i].Name = name } if infoOk { products[i].Info = info } if priceOk { products[i].Price = price } product = products[i] break } } return product, nil }, },
/* Delete product by id http://localhost:8080/product?query=mutation+_{delete(id:1){id,name,info,price}} */ "delete": &graphql.Field{ Type: productType, Description: "Delete product by id", Args: graphql.FieldConfigArgument{ "id": &graphql.ArgumentConfig{ Type: graphql.NewNonNull(graphql.Int), }, }, Resolve: func(params graphql.ResolveParams) (interface{}, error) { id, _ := params.Args["id"].(int) product := Product{} for i, p := range products { if int64(id) == p.ID { product = products[i] // Remove from product list products = append(products[:i], products[i+1:]...) } }
return product, nil }, }, },})
var schema, _ = graphql.NewSchema( graphql.SchemaConfig{ Query: queryType, Mutation: mutationType, },)
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("errors: %v", result.Errors) } return result}
func main() { http.HandleFunc("/product", func(w http.ResponseWriter, r *http.Request) { result := executeQuery(r.URL.Query().Get("query"), schema) json.NewEncoder(w).Encode(result) })
fmt.Println("Server is running on port 8080") http.ListenAndServe(":8080", nil)}