使用 go-gin 和 mgo 从 mongoDB 获取 id 轮询时出错

Question

如何使用go-gin和MongoDB按id查询民意调查，我已经尝试了几种方法，但仍然遇到错误(未找到(，似乎找不到我的代码，我的数据库在mongoDB上：

type Poll struct {
//ID        string `json:"_id,omitempty"`
ID        bson.ObjectId     `json:"id,omitempty" bson:"_id,omitempty"`
Firstname string            `json:"firstname,omitempty"`
Lastname  string            `json:"lastname,omitempty"`
Poll      string            `json:"poll,omitempty"`
//  Address   *Address `json:"address,omitempty"`
}
var (
// Session stores mongo session
Session *mgo.Session
// Mongo stores the mongodb connection string information
Mongo *mgo.DialInfo
)
const (
// MongoDBUrl is the default mongodb url that will be used to connect to the
// database.
MongoDBUrl = "mongodb://localhost:27017/smartpoll"
// CollectionPoll holds the name of the poll collection
CollectionPoll = "polls"
)
// Connect connects to mongodb
func Connect() {
uri := os.Getenv("MONGODB_URL")
if len(uri) == 0 {
uri = MongoDBUrl
}
mongo, err := mgo.ParseURL(uri)
s, err := mgo.Dial(uri)
if err != nil {
fmt.Printf("Can't connect to mongo, go error %vn", err)
panic(err.Error())
}
s.SetSafe(&mgo.Safe{})
fmt.Println("Connected to", uri)
Session = s
Mongo = mongo
}

func init() {
Connect()
}
func main() {
port := os.Getenv("PORT")
if port == "" {
log.Fatal("$PORT must be set")
}

router := gin.Default()
router.Use(ConnectMiddleware)
router.GET("/", func (c *gin.Context) {
c.JSON(http.StatusOK, gin.H{"message": "OK"})
})
router.GET("/polls/:_id", pollsByID)
router.Run(":" + port)
}


func ConnectMiddleware(c * gin.Context) {
c.Set("db", Session.DB(Mongo.Database))
c.Next()
}
func pollsByID(c * gin.Context) {
db := c.MustGet("db").(*mgo.Database)
id := c.Param("id")
poll := []Poll{}
//  err := db.C(CollectionPoll).Find(id).One(&poll)
err := db.C(CollectionPoll).Find(bson.M{"_id": id}).One(&poll)

if err != nil {
//c.Error(err)
//panic(err)
log.Println(err)
}
result := gin.H{"payload": poll}
c.Writer.Header().Set("Content-Type", "application/json")
c.JSON(200, result)
}

我的数据库如下：

{
"_id" : ObjectId("58d9cf1cdf353f3d2f5951b4"),
"id" : "1",
"firstname" : "Sam",
"lastname" : "Smith",
"poll" : "Who is the Richest in the World"
}

Answer 1

您的 ID 是ObjectId，但您的输入是string。您需要使用bson.ObjectIdHex将string解析为ObjectId：

err := db.C(CollectionPoll).FindId(bson.ObjectIdHex(id)).One(&poll)

Answer 2

从数组更改轮询：

polls := []Poll{}

自：

polls := Poll{}