go-graphql

Posted 2021-04-30 Golang基础教程

关于golang的graphql入门学习教程,非常简单的数据结构,代码解释在注释里面.

package main
import (
   "encoding/json"
   "errors"
   "fmt"
   "github.com/graphql-go/graphql"
   "github.com/graphql-go/graphql-go-handler"
   uuid "github.com/satori/go.uuid"
   "net/http"
)

// Good 商品
type Good struct {
   ID    string  `json:"id"`    // id
   Name  string  `json:"name"`  // 名称
   Price float64 `json:"price"` // 价格
   Url   string  `json:"url"`   // url地址
}

var CacheMap = make(map[string]interface{})

// goodType 商品类型
var goodType = graphql.NewObject(
   graphql.ObjectConfig{
      Name: "Good",
      Fields: graphql.Fields{
         "id": &graphql.Field{
            Type:        graphql.String,
            Description: "id",
         }, "name": &graphql.Field{
            Type:        graphql.String,
            Description: "商品名称",
         }, "price": &graphql.Field{
            Description: "商品价格",
            Type:        graphql.Float,
         }, "url": &graphql.Field{
            Type:        graphql.String,
            Description: "商品url地址",
         },
      },
      Description: "商品参数类型",
   },
)

// goodListType 商品列表类型
var goodListType = graphql.NewList(goodType)

// queryType query 下的定义
var queryType = graphql.NewObject(
   graphql.ObjectConfig{
      Name: "Query",
      Fields: graphql.Fields{ // 无需处理参数
         "goodList": &graphql.Field{
            Type: goodListType, // 处理结构体的回调函数，直接返回处理完成的结构体即可
            Resolve: func(p graphql.ResolveParams) (ret interface{}, err error) {
               var data []Good
               for _, v := range CacheMap {
                  fmt.Printf("%T", v)
                  switch _v := v.(type) {
                  case *Good:
                     data = append(data, *_v)
                  }
               }

               ret = data
               return
            },
            Description: "获取商品列表",
         }, // 参数是id
         "good": &graphql.Field{
            Type: goodType,
            Args: graphql.FieldConfigArgument{
               "id": &graphql.ArgumentConfig{
                  Type:        graphql.String,
                  Description: "商品id",
               },
            },
            Resolve: func(p graphql.ResolveParams) (ret interface{}, err error) { // 获取参数
               if _v, isOK := p.Args["id"].(string); isOK {
                  data := CacheMap[_v]
                  ret = data
                  return
               } else {
                  err = errors.New("Field 'goods' is missing required arguments: id. ")
                  return
               }
            },
            Description: "商品",
         },
      },
   },
)

// goodInputType 商品输入参数类型定义
var goodInputType = graphql.NewInputObject(
   graphql.InputObjectConfig{
      Name: "goodInput",
      Fields: graphql.InputObjectConfigFieldMap{
         "name": &graphql.InputObjectFieldConfig{
            Type:        graphql.String,
            Description: "名称",
         }, "price": &graphql.InputObjectFieldConfig{
            Description: "价格",
            Type:        graphql.Float,
         }, "url": &graphql.InputObjectFieldConfig{
            Type:        graphql.String,
            Description: "url",
         },
      },
      Description: "输入",
   },
)

// mutationType mutation
var mutationType = graphql.NewObject(
   graphql.ObjectConfig{
      Name: "Mutation",
      Fields: graphql.Fields{
         "addGood": &graphql.Field{
            Description: "添加商品",
            Type:        goodType,
            Args: graphql.FieldConfigArgument{
               "input": &graphql.ArgumentConfig{
                  Type:        goodInputType,
                  Description: "输入参数类型",
               },
            },
            Resolve: func(p graphql.ResolveParams) (ret interface{}, err error) {
               input, isOk := p.Args["input"].(map[string]interface{})
               if !isOk {
                  err = errors.New("Field 'addGoods' is missing required arguments: input. ")
                  return
               }
               var g = new(Good)
               // 生成一个id
               g.ID = uuid.NewV4().String()
               data, _err := json.Marshal(input)
               if _err != nil {
                  err = _err
                  return
               }
               if err = json.Unmarshal([]byte(data), &g); err != nil {
                  return
               }

               // 用map保存数据
               CacheMap[g.ID] = g
               ret = g
               return
            },
         },
      },
   },
)

// schema 开机模式
var schema, _ = graphql.NewSchema(
   graphql.SchemaConfig{
      Query:        queryType,
      Mutation:     mutationType,
      Subscription: queryType,
   },
)

// Register 注册路由
func Register() *handler.Handler {
   h := handler.New(&handler.Config{
      Schema:   &schema,
      Pretty:   true,
      GraphiQL: true,
   })

   return h
}

func main() {
   h := Register()
   http.Handle("/", h)
   http.ListenAndServe("127.0.0.1:8081", nil)
}