이번 주에 내가 무엇을 배웠습니까?

37301 단어 graphql todayilearned go programming

Golang에서 GraphQL을 구현하는 방법이 궁금합니다. 검색을 시도하고 도움이 될 라이브러리를 찾았습니다. 목록은 다음과 같습니다.

graphql-go . GraphQL을 구현하는 데 도움이 되도록 이것을 사용합니다.

echo . 이 라이브러리를 사용하여 라우팅 및 HTTP 처리기를 구현하는 데 도움을 받습니다.

gorm . 저는 이 라이브러리를 사용하여 데이터베이스 쪽을 구현하는 데 도움을 줍니다. 이 라이브러리는 ORM입니다.

코드 ???

내 Github 저장소를 방문하는 것이 좋습니다.

bervProject / go-마이크로서비스-보일러플레이트

Go 마이크로서비스 상용구

go-마이크로서비스-보일러플레이트

Go 마이크로서비스 상용구

특허

MIT

View on GitHub

코드는 다음과 같습니다.

package main

import (
    "database/sql"
    "fmt"
    "log"
    "net/http"
    "os"
    "time"

    "github.com/graphql-go/graphql"
    "github.com/labstack/echo/v4"
    "gorm.io/driver/postgres"
    "gorm.io/gorm"
)

type PostData struct {
    Query     string                 `json:"query"`
    Operation string                 `json:"operation"`
    Variables map[string]interface{} `json:"variables"`
}

type User struct {
    ID           uint
    Name         string
    Email        *string
    Age          uint8
    Birthday     *time.Time
    MemberNumber sql.NullString
    ActivatedAt  sql.NullTime
    CreatedAt    time.Time
    UpdatedAt    time.Time
}

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() {
    dsn := os.Getenv("DB_CONNECTION_STRING")
    db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})
    if err != nil {
        log.Fatalf("failed to connect database, error: %v", err)
    }
    db.AutoMigrate(&User{})
    // Schema
    userType := graphql.NewObject(
        graphql.ObjectConfig{
            Name: "User",
            Fields: graphql.Fields{
                "id": &graphql.Field{
                    Type: graphql.Int,
                },
                "name": &graphql.Field{
                    Type: graphql.String,
                },
            },
        },
    )

    fields := graphql.Fields{
        "hello": &graphql.Field{
            Type: graphql.String,
            Resolve: func(p graphql.ResolveParams) (interface{}, error) {
                return "world", nil
            },
        },
    }
    mutationFields := graphql.Fields{
        "createUser": &graphql.Field{
            Type:        userType,
            Description: "Create New User",
            Args: graphql.FieldConfigArgument{
                "name": &graphql.ArgumentConfig{
                    Type: graphql.NewNonNull(graphql.String),
                },
            },
            Resolve: func(params graphql.ResolveParams) (interface{}, error) {
                user := User{
                    Name: params.Args["name"].(string),
                }
                result := db.Create(&user)
                if result.Error != nil {
                    return nil, result.Error
                }
                return user, nil
            },
        },
    }
    rootQuery := graphql.ObjectConfig{Name: "RootQuery", Fields: fields}
    rootMutation := graphql.ObjectConfig{Name: "RootMutation", Fields: mutationFields}
    schemaConfig := graphql.SchemaConfig{
        Query:    graphql.NewObject(rootQuery),
        Mutation: graphql.NewObject(rootMutation),
    }
    schema, err := graphql.NewSchema(schemaConfig)
    if err != nil {
        log.Fatalf("failed to create new schema, error: %v", err)
    }
    e := echo.New()
    e.GET("/", func(c echo.Context) error {
        return c.String(http.StatusOK, "Hello, World!")
    })
    e.POST("/graphql", func(c echo.Context) error {
        data := new(PostData)
        if err := c.Bind(data); err != nil {
            return err
        }
        result := graphql.Do(graphql.Params{
            Schema:         schema,
            RequestString:  data.Query,
            VariableValues: data.Variables,
            OperationName:  data.Operation,
        })
        return c.JSON(http.StatusOK, result)
    })
    e.Logger.Fatal(e.Start(":1323"))
}

TLDR

중요 부품

우리는 3개의 중요한 부분을 가질 것입니다. 갑시다.

Echo를 시작하고 GraphQL 경로 및 공통 실행을 정의하여 GraphQL Query 또는 GraphQL Mutation을 호출합니다.

// data struct to represent the request of GraphQL.
type PostData struct {
    Query     string                 `json:"query"`
    Operation string                 `json:"operation"`
    Variables map[string]interface{} `json:"variables"`
}

func main() {
  // ... rest of codes

  // initiate echo
  e := echo.New()

  // initiate path and handler
  e.POST("/graphql", func(c echo.Context) error {
        // bind body message of query/mutation to PostData
    data := new(PostData)
    if err := c.Bind(data); err != nil {
        return err
    }
        // call the graphql using the data provided and already binded with PostData
    result := graphql.Do(graphql.Params{
        Schema:         schema,
        RequestString:  data.Query,
        VariableValues: data.Variables,
        OperationName:  data.Operation,
    })
        // return the result as it is and expect will success
        // we will learn in the next post about error handling
    return c.JSON(http.StatusOK, result)
  })
    e.Logger.Fatal(e.Start(":1323"))
}

데이터베이스 및 ORM 시작

// sample table definition
type User struct {
    ID           uint
    Name         string
    Email        *string
    Age          uint8
    Birthday     *time.Time
    MemberNumber sql.NullString
    ActivatedAt  sql.NullTime
    CreatedAt    time.Time
    UpdatedAt    time.Time
}


func main() {
        // you may change the os.Getenv to string directly for testing in case you don't have the env.
        dsn := os.Getenv("DB_CONNECTION_STRING")
        // initiate the database connection
        // since I use postgres, so the open come from postgres driver, you may use other drivers if you are using another database.
    db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})
    if err != nil {
        log.Fatalf("failed to connect database, error: %v", err)
    }
        // we are doing auto migrate
    db.AutoMigrate(&User{})
        // ... rest of codes
}

GraphQL 스키마, 쿼리 및 변형 시작

func main() {
       // ... rest of codes

      // initiate user object
        userType := graphql.NewObject(
        graphql.ObjectConfig{
            Name: "User",
            Fields: graphql.Fields{
                "id": &graphql.Field{
                    Type: graphql.Int,
                },
                "name": &graphql.Field{
                    Type: graphql.String,
                },
            },
        },
    )

        // sample to define queries
    fields := graphql.Fields{
        "hello": &graphql.Field{
            Type: graphql.String,
            Resolve: func(p graphql.ResolveParams) (interface{}, error) {
                return "world", nil
            },
        },
    }
        // sample to define mutations
    mutationFields := graphql.Fields{
        "createUser": &graphql.Field{
            Type:        userType,
            Description: "Create New User",
            Args: graphql.FieldConfigArgument{
                "name": &graphql.ArgumentConfig{
                    Type: graphql.NewNonNull(graphql.String),
                },
            },
            Resolve: func(params graphql.ResolveParams) (interface{}, error) {
                user := User{
                    Name: params.Args["name"].(string),
                }
                result := db.Create(&user)
                if result.Error != nil {
                    return nil, result.Error
                }
                return user, nil
            },
        },
    }
        // merge the queries into rootQuery
    rootQuery := graphql.ObjectConfig{Name: "RootQuery", Fields: fields}
        // merge the mutation into rootMutation
    rootMutation := graphql.ObjectConfig{Name: "RootMutation", Fields: mutationFields}
        // merge query & mutation to 1 schema
    schemaConfig := graphql.SchemaConfig{
        Query:    graphql.NewObject(rootQuery),
        Mutation: graphql.NewObject(rootMutation),
    }
        // initiate the schema
    schema, err := graphql.NewSchema(schemaConfig)
    if err != nil {
        log.Fatalf("failed to create new schema, error: %v", err)
    }
       // ... rest of codes
}