[英]Append new sub document to an array in the main struct
I have the following go structs in my MongoDB database: 我的MongoDB数据库中有以下go结构:
type Station struct {
ID bson.ObjectId `bson:"_id" json:"id"`
Name string `bson:"name" json:"name"`
Sensors []Sensor `bson:"sensors" json:"sensors"`
}
type Sensor struct {
ID bson.ObjectId `bson:"_id" json:"id"`
Type string ` bson:"type" json:"type"`
Value float64 `bson:"value" json:"value"`
}
When I make a POST request at the endpoint localhost:3000/stations/<IDofTheStation/sensors
, it should add a new sensor to the specified station. 当我在端点localhost:3000/stations/<IDofTheStation/sensors
处发出POST请求时,它应该向指定的工作站添加一个新的传感器。
Currently I have this code 目前我有此代码
func AddSensorToStation(w http.ResponseWriter, r *http.Request) {
defer r.Body.Close()
params := mux.Vars(r)
station, err := dao.FindById(params["id"])
if err != nil {
respondWithError(w, http.StatusBadRequest, "Invalid Station ID")
return
}
sensor := Sensor{Type: "test"}
station.Sensors = append(station.Sensors, sensor)
if err := dao.Update(station); err != nil {
respondWithError(w, http.StatusInternalServerError, err.Error())
return
}
respondWithJson(w, http.StatusOK, station)
}
The problem is that it does not automatically generate an ID for the new sensor that I want to add, thus it throws the error " ObjectIDs must be exactly 12 bytes long (got 0) " 问题在于,它不会自动为我要添加的新传感器生成ID,因此会引发错误“ ObjectID必须正好为12个字节长(得到0) ”
What is the best way to append a new Sensor instance to the Sensors array where the DB generates the id for the sensor? 将新的Sensor实例附加到Sensors数组(数据库将为其生成ID的传感器)的最佳方法是什么?
MongoDB won't ever generate an ID
for a sub-document on the server-side. MongoDB永远不会在服务器端为子文档生成ID
。
Do you really need the ID
on the sensor? 您真的需要传感器上的ID
吗? MongoDB won't complain about a sub-document not having an ID
(or its ID
being in a wrong format) because a subdocument can have an arbitrary structure - so it can easily exist without an ID
. MongoDB不会抱怨子文档没有ID
(或者其ID
格式错误),因为子文档可以具有任意结构-因此无需ID
即可轻松存在。
If you do need the ID for some reason then you can, of course, create one on the client side: 如果由于某种原因确实需要ID,那么您当然可以在客户端创建一个ID:
sensor.ID := bson.NewObjectId()
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