I have a very simple HTP server written in Go which serves my AngularJS front end data from a mongodb instance through an API.
Here is the code:
// ReceiveData - used to handle incoming data
func ReceiveData(w http.ResponseWriter, r *http.Request) {
if r.Method != "POST" {
http.NotFound(w, r)
return
}
body, err := ioutil.ReadAll(r.Body)
if err != nil {
panic(err)
}
// database
session, err := mgo.Dial("localhost")
if err != nil {
panic(err)
} else {
fmt.Println("session created")
database := session.DB("schedule_calculator")
collection := database.C("schedule_save")
num, err := collection.Count()
if err == nil {
fmt.Println("schedule_save collection count = ", num)
mongodbData := SavedData{ID: bson.NewObjectId(), Data: string(body), Date: time.Now()}
collection.Insert(mongodbData)
num, _ := collection.Count()
fmt.Println("new count: ", num)
} else {
fmt.Println("schedule_save error - ", err)
}
}
if err := json.NewEncoder(w).Encode("todos"); err != nil {
panic(err)
}
}
type SavedData struct {
ID bson.ObjectId `bson:"_id"`
Data string
Date time.Time
}
// SendData - Called by UI to get saved data
func SendData(w http.ResponseWriter, r *http.Request) {
fmt.Println("SendData function")
session, err := mgo.Dial("localhost")
defer closeSession(session)
if err != nil {
panic(err)
} else {
fmt.Println("session created")
database := session.DB("schedule_calculator")
collection := database.C("schedule_save")
num, err := collection.Count()
if err == nil {
fmt.Println("schedule_save collection count = ", num)
var myData SavedData
dbSize, err2 := collection.Count()
if err2 != nil {
panic(err2)
}
if dbSize > 0 {
// db not empty
err2 = collection.Find(nil).Skip(dbSize - 1).One(&myData)
if err2 != nil {
// TODO: handle error
panic(err2)
}
// fmt.Println(myData.Data)
w.Header().Set("Content-Type", "application/json; charset=UTF-8")
w.WriteHeader(http.StatusOK)
if err := json.NewEncoder(w).Encode(myData.Data); err != nil {
// TODO: handle error
panic(err)
}
} else {
// db empty
fmt.Println("DB is empty")
}
} else {
fmt.Println("schedule_save error - ", err)
}
}
}
// closes the mongodb session
// TODO: make it use only 1 session
func closeSession(session *mgo.Session) {
session.Close()
fmt.Println("session closed")
}
and this is what I get in the console after some short interaction with the API:
2016-08-10T19:22:59.734+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55401 #60 (6 connections now open)
2016-08-10T19:22:59.740+0300 I NETWORK [conn60] end connection 127.0.0.1:55401 (5 connections now open)
2016-08-10T19:23:58.794+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55405 #61 (6 connections now open)
2016-08-10T19:23:58.800+0300 I NETWORK [conn61] end connection 127.0.0.1:55405 (5 connections now open)
2016-08-10T19:24:24.219+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55411 #62 (6 connections now open)
2016-08-10T19:24:24.225+0300 I NETWORK [conn62] end connection 127.0.0.1:55411 (5 connections now open)
2016-08-10T19:25:56.149+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55434 #63 (6 connections now open)
2016-08-10T19:25:56.155+0300 I NETWORK [conn63] end connection 127.0.0.1:55434 (5 connections now open)
2016-08-10T19:33:54.127+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55460 #64 (6 connections now open)
2016-08-10T19:33:54.133+0300 I NETWORK [conn64] end connection 127.0.0.1:55460 (5 connections now open)
2016-08-10T19:35:12.060+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55476 #65 (6 connections now open)
2016-08-10T19:35:12.066+0300 I NETWORK [conn65] end connection 127.0.0.1:55476 (5 connections now open)
2016-08-10T19:35:22.827+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55477 #66 (6 connections now open)
2016-08-10T19:35:22.833+0300 I NETWORK [conn66] end connection 127.0.0.1:55477 (5 connections now open)
2016-08-10T19:35:37.720+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55478 #67 (6 connections now open)
2016-08-10T19:35:52.725+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55487 #68 (7 connections now open)
2016-08-10T19:36:20.498+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55488 #69 (8 connections now open)
2016-08-10T19:36:20.508+0300 I NETWORK [conn69] end connection 127.0.0.1:55488 (7 connections now open)
2016-08-10T19:36:33.100+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55490 #70 (8 connections now open)
2016-08-10T19:36:37.155+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55492 #71 (9 connections now open)
2016-08-10T19:36:48.105+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55493 #72 (10 connections now open)
2016-08-10T19:36:50.284+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55494 #73 (11 connections now open)
2016-08-10T19:36:52.157+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55495 #74 (12 connections now open)
2016-08-10T19:36:53.328+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55496 #75 (13 connections now open)
2016-08-10T19:37:01.375+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55497 #76 (14 connections now open)
2016-08-10T19:37:05.287+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55498 #77 (15 connections now open)
2016-08-10T19:37:05.827+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55499 #78 (16 connections now open)
2016-08-10T19:37:05.836+0300 I NETWORK [conn78] end connection 127.0.0.1:55499 (15 connections now open)
2016-08-10T19:37:08.333+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55500 #79 (16 connections now open)
2016-08-10T19:37:16.376+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55521 #80 (17 connections now open)
2016-08-10T19:37:23.323+0300 W NETWORK [HostnameCanonicalizationWorker] Failed to obtain name info for: [ (192.168.0.102, "nodename nor servname provided, or not known"), (192.168.0.102, "nodename nor servname provided, or not known") ]
2016-08-10T19:40:41.079+0300 I NETWORK [initandlisten] connection accepted from 127.0.0.1:55546 #81 (18 connections now open)
2016-08-10T19:40:41.087+0300 I NETWORK [conn81] end connection 127.0.0.1:55546 (17 connections now open)
I am very new to Go, so this was the simplest way I managed to make it work however I would really like to know how to limit the opened connections to 1.
