服务计算学习之路四——简单 web 服务与客户端开发实战

简单 web 服务与客户端开发实战

团队项目连接：

后端部分，前端部分

自己实现的部分

• 实现后端中负责网络连接的主要部分main.go文件内容

实现过程

• Step1：仿照 https://swapi.co/ 网站的API结构构造Planet，Species，People，Films，Starships，Vehicles结构，用Gragpql的API创建，例如Planet对应的graphql.Object：

  func createPlanetType() *graphql.Object {
  	return graphql.NewObject(graphql.ObjectConfig{
  		Name: "Planet",
  		Fields: graphql.Fields{
  			"Name": &graphql.Field{
  				Type: graphql.String,
  			},
  			"OrbitalPeriod": &graphql.Field{
  				Type: graphql.String,
  			},
  			"RotationPeriod": &graphql.Field{
  				Type: graphql.String,
  			},
  			"Diameter": &graphql.Field{
  				Type: graphql.String,
  			},
  			"Climate": &graphql.Field{
  				Type: graphql.String,
  			},
  			"Gravity": &graphql.Field{
  				Type: graphql.String,
  			},
  			"Terrain": &graphql.Field{
  				Type: graphql.String,
  			},
  			"SurfaceWater": &graphql.Field{
  				Type: graphql.String,
  			},
  			"Population": &graphql.Field{
  				Type: graphql.String,
  			},
  			"ResidentURLs": &graphql.Field{
  				Type: graphql.NewList(graphql.String),
  			},
  			"FilmURLs": &graphql.Field{
  				Type: graphql.NewList(graphql.String),
  			},
  			"Created": &graphql.Field{
  				Type: graphql.String,
  			},
  			"Edited": &graphql.Field{
  				Type: graphql.String,
  			},
  			"URL": &graphql.Field{
  				Type: graphql.String,
  			},
  		},
  	})
  }
  

  Species，People，Films，Starships，Vehicles的代码也类似。

• Step2：然后我们的数据是用boltDB保存在服务器中，所以对API的请求，如果请求格式正确，我们要根据请求内容返回对应的Planet，Species，People，Films，Starships，Vehicles相应字段的数据，例如从数据库获取People内容的数据：

  func fetchPeopleByiD(id int) (*Person, error) {
  	result := Person{}
  	db, _ := setupDB()
  
  	db.View(func(tx *bolt.Tx) error {
  		b := tx.Bucket([]byte("DB")).Bucket([]byte("People"))
  		v := string(b.Get([]byte(strconv.Itoa(id))))
  		err := json.Unmarshal([]byte(v), &result)
  		if err != nil {
  			return fmt.Errorf("could not Unmarshal json string: %v", err)
  		}
  
  		return nil
  	})
  	db.Close()
  	return &result, nil
  }
  

  Planet，Species，Films，Starships，Vehicles的也类似。

• Step3：最后，在main函数主体里定义好对请求返回数据的处理，这部分类似步骤1的操作：

  rootQuery := graphql.NewObject(graphql.ObjectConfig{
  		Name: "Query",
  		Fields: graphql.Fields{
  			
  			"planets": &graphql.Field{
  				Type: createPlanetType(),
  				Args: graphql.FieldConfigArgument{
  					"id": &graphql.ArgumentConfig{
  						Type: graphql.NewNonNull(graphql.Int),
  					},
  				},
  				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
  					id := p.Args["id"]
  					v, _ := id.(int)
  					log.Printf("fetching planet with id: %d", v)
  					return fetchPlanetByiD(v)
  				},
  			},
  			"species": &graphql.Field{
  				Type: createSpeciesType(),
  				Args: graphql.FieldConfigArgument{
  					"id": &graphql.ArgumentConfig{
  						Type: graphql.NewNonNull(graphql.Int),
  					},
  				},
  				Resolve: func(params graphql.ResolveParams) (interface{}, error) {
  					id := params.Args["id"]
  					v, _ := id.(int)
  					log.Printf("fetching species with id: %d", v)
  					return fetchSpeciesByPostID(v)
  				},
  			},
  
  			"people": &graphql.Field{
  				Type: createPeopleType(),
  				Args: graphql.FieldConfigArgument{
  					"id": &graphql.ArgumentConfig{
  						Type: graphql.NewNonNull(graphql.Int),
  					},
  				},
  				Resolve: func(params graphql.ResolveParams) (interface{}, error) {
  					id := params.Args["id"]
  					v, _ := id.(int)
  					log.Printf("fetching people with id: %d", v)
  					return fetchPeopleByiD(v)
  				},
  			},
  			"films": &graphql.Field{
  				Type: createFilmType(),
  				Args: graphql.FieldConfigArgument{
  					"id": &graphql.ArgumentConfig{
  						Type: graphql.NewNonNull(graphql.Int),
  					},
  				},
  				Resolve: func(params graphql.ResolveParams) (interface{}, error) {
  					id := params.Args["id"]
  					v, _ := id.(int)
  					log.Printf("fetching films with id: %d", v)
  					return fetchFilmByiD(v)
  				},
  			},
  			"starships": &graphql.Field{
  				Type: createStarshipType(),
  				Args: graphql.FieldConfigArgument{
  					"id": &graphql.ArgumentConfig{
  						Type: graphql.NewNonNull(graphql.Int),
  					},
  				},
  				Resolve: func(params graphql.ResolveParams) (interface{}, error) {
  					id := params.Args["id"]
  					v, _ := id.(int)
  					log.Printf("fetching starships with id: %d", v)
  					return fetchStarshipByiD(v)
  				},
  			},
  			"vehicles": &graphql.Field{
  				Type: createVehicleType(),
  				Args: graphql.FieldConfigArgument{
  					"id": &graphql.ArgumentConfig{
  						Type: graphql.NewNonNull(graphql.Int),
  					},
  				},
  				Resolve: func(params graphql.ResolveParams) (interface{}, error) {
  					id := params.Args["id"]
  					v, _ := id.(int)
  					log.Printf("fetching Vehicles with id: %d", v)
  					return fetchVehicleByiD(v)
  				},
  			},
  			
  		},
  	})
  

  然后利用graghql提供的schema和handler对请求进行处理并在3000端口监听：

  schema, err := graphql.NewSchema(graphql.SchemaConfig{
  		Query: rootQuery,
  	})
  
  	if err != nil {
  		log.Fatalf("failed to create new schema, error: %v", err)
  	}
  	handler := gqlhandler.New(&gqlhandler.Config{
  		Schema: &schema,
  	})
  	http.Handle("/graphql", handler)
  	log.Println("Server started at http://localhost:3000/graphql")
  	log.Fatal(http.ListenAndServe(":3000", nil))
  

小总结

由于时间关系，关于实现的方法介绍得不太清晰，如需进一步了解请先查看一下资料:
graghql-go官网资料：https://godoc.org/github.com/graphql-go/graphql
Qraqhql官网资料：http://graphql.cn/

我实现的代码的github连接

https://github.com/LittleFish33/Server-Computing-Swapi/blob/master/main.go