在上下文中使用 mgo

Question

我一直在为我的 API 使用 mgo，但我在我的 Mongo 数据库中看到许多当前连接（同时使用少于 5 个设备进行测试）。通过在我的 Mongo 服务器中执行 db.serverStatus().connections，我得到：{ "current" : 641, "available" : 838219, "totalCreated" : 1136 }。下面我将我的问题记录在 mgo 的 Github (Issue #429):

我在 Web 服务器中使用 mgo 的方式是否正确？如果没有，你能给我一个完整的例子吗？

此代码不起作用，几乎可以将其视为伪代码（因为缺少部分，例如导入或配置来自何处和模型），但这正是我使用 mgo 的方式。

我必须澄清一下，我正在构建一个 API 供多个移动设备和网络应用程序使用。

main.go

func main() {
    mongoDBDialInfo := &mgo.DialInfo{
        Addrs:    []string{config.DatabaseURL},
        Timeout:  60 * time.Second,
        Database: config.DatabaseName,
        Username: config.DatabaseUsername,
        Password: config.DatabasePassword,
    }

    db, err := mgo.DialWithInfo(mongoDBDialInfo)

    if err != nil {
        log.Fatal("Cannot Dial Mongo: ", err)
    }

    defer db.Close() 
    db.SetMode(mgo.Monotonic, true)

    phoneIndex := mgo.Index{
        Key:        []string{"pp"},
        Unique:     true,
        DropDups:   true,
        Background: true,
        Sparse:     true,
    }

    err = db.DB(config.DatabaseName).C("users").EnsureIndex(phoneIndex)
    if err != nil {
        panic(err)
    }

    router := mux.NewRouter()
    router.HandleFunc("/login", publicWithDB(login, db)).Methods("POST")

    if err := http.ListenAndServe(":5000", router); err != nil {
        log.Fatal(err)
    }
}

func publicWithDB(fn http.HandlerFunc, db *mgo.Session) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        dbsession := db.Copy()
        defer dbsession.Close()
        fn(w, r.WithContext(context.WithValue(r.Context(), contextKeyDatabase, dbsession)))
    }
}

func login(w http.ResponseWriter, r *http.Request) {
    r.ParseForm() // Parses the request body
    device := r.Form.Get("device")

    var deviceid bson.ObjectId
    if bson.IsObjectIdHex(device) {
        deviceid = bson.ObjectIdHex(device)
    }

    db := r.Context().Value(contextKeyDatabase).(*mgo.Session)

    var device models.Device
    err := db.DB(config.DatabaseName).C("devices").FindId(deviceid).One(&device)

    w.WriteHeader(200)
    w.Write([]byte(utils.ResponseToString(models.Response{Status: 200, Message: "asdasd", Data: device})))

}

我发布这个是因为我找不到完整的实现。

Answer 1

下面是一个示例，说明我自己和其他人如何使用 Go 构建 Web 应用程序。此代码未经测试，仅供参考。它缺少导入并且可能有错误。

编辑添加了一个中间件示例。

main.go

package main

func main() {
    mongoDBDialInfo := &mgo.DialInfo{
        Addrs:    []string{config.DatabaseURL},
        Timeout:  60 * time.Second,
        Database: config.DatabaseName,
        Username: config.DatabaseUsername,
        Password: config.DatabasePassword,
    }

    db, err := mgo.DialWithInfo(mongoDBDialInfo)

    if err != nil {
        log.Fatal("Cannot Dial Mongo: ", err)
    }

    defer db.Close() 
    db.SetMode(mgo.Monotonic, true)

    phoneIndex := mgo.Index{
        Key:        []string{"pp"},
        Unique:     true,
        DropDups:   true,
        Background: true,
        Sparse:     true,
    }

    err = db.DB(config.DatabaseName).C("users").EnsureIndex(phoneIndex)
    if err != nil {
        panic(err)
    }

    mgoAdapter := mongo.NewAdapter(db, config.DatabaseName)
    deviceStore := mongo.NewDeviceStore(mgoAdapter)
    userStore := mongo.NewUserStore(mgoAdapter)

    loginController := controllers.NewLoginController(deviceStore)

    router := mux.NewRouter()
    router.HandleFunc("/login", middleware.AuthorizeUser(userStore)(http.HandlerFunc(loginController.Login)).Methods("POST")

    if err := http.ListenAndServe(":5000", router); err != nil {
        log.Fatal(err)
    }
}

controllers/login.go

package controllers

type LoginController struct { 
    store DeviceStore
}

func NewLoginController(store stores.DeviceStore) *LoginController {
    return &LoginController{
        store: store,
    }
}

func (c *LoginController) Login(w http.ResponseWriter, r *http.Request) {
    r.ParseForm() // Parses the request body
    device := r.Form.Get("device")
    data, err := c.store.FindByDevice(device)

    var respose models.Response
    if err != nil {
        w.WriteHeader(500)
        response = models.Response{Status: 500, Message: fmt.Sprintf("error: %s", err)}
    } else if data == nil {
        w.WriteHeader(404)
        response = models.Response{Status: 404, Message: "device not found"}
    } else {
        response = models.Response{Status: 200, Message: "device found", Data: data}
    }

    // Write sets header to 200 if it hasn't been set already
    w.Write([]byte(utils.ResponseToString(response)))
}

stores/stores.go

package stores

type DeviceStore interface {
    FindByDevice(device string) (*models.Device, error)
}

type UserStore interface {
    FindByToken(token string) (*models.User, error)
}

middleware/auth.go

package middleware

func AuthorizeUser(store stores.UserStore) func(h *http.Handler) http.Handler {
    return func(h *http.Handler) http.Handler {
        return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            // Logic for authorizing user
            // Could also store user in the request context
        })
    }
}

mongo/mongo.go

package mongo

type Adapter struct {
    session      *mgo.Session
    databaseName string
}

func NewAdapter(session *mgo.Session, dbName string) *Adapter {
    return &Adapter{session: session, databaseName: dbName}
}

type deviceStore struct {
    *Adapter
}

func NewDeviceStore(adapter *Adapter) stores.DeviceStore {
    return &deviceStore{adapter}
}

const devices = "devices"

func (s *deviceStore) FindByDevice(d string) (*models.Device, err) {
    sess := s.session.copy()
    defer sess.close()

    var deviceID bson.ObjectId
    if bson.IsObjectIdHex(d) {
        deviceID = bson.ObjectIdHex(d)
    }

    var device models.Device
    err := db.DB(s.databaseName).C(devices).FindId(deviceID).One(&device)
    if err == mgo.ErrNotFound {
        return nil, nil
    }
    return &device, err
}

type userStore struct {
    *Adapter
}

const users = "users"

func NewUserStore(adapter *Adapter) stores.UserStore {
    return &userStore{adapter}
}

func (s *userStore) GetUserByToken(token string) (*models.User, error) {
    sess := s.session.copy()
    defer sess.close()

    var user models.User
    err := db.DB(s.databaseName).C(users).Find(bson.M{"token": token}).One(&user)
    if err == mgo.ErrNotFound {
        return nil, nil
    }

    return &user, err
}

在上下文中使用 mgo

Using mgo with context

go

mongodb

mgo