How can we update a record by a http post method in GoLang? - http

Question

Problem description:
I am learning Golang to implement the REST API for a small project.
I was following this small example to get the some idea how to connect things.
However, it looks like there are some bugs in the sample example, that i could not get the expected response in postman after hitting the endpoints.
I have fixed it by adding the missing functions (HandleFunc functions) to make it work.
Problem Description:
However, I still have an issue with CreateEvent section.
The expectation is that after using POST method with a given sample Event (json format) like below, event list is updated.
{
"id": "23",
"title": "This is simple Go lang title for test!",
"Description":"In this course you will learn REST api implementation in Go lang"
}
But after reaching the "http://localhost:8080/events" endpoint in which I defined to return all the events (1 defined inside code, the other should be added by calling CreateEvent function) i get only one of the event (hard coded one inside code only) in response.
Here is the complete code.
I appreciate for any suggestions/comments.
package main
import (
"fmt"
"log"
"net/http"
"io/ioutil"
"encoding/json"
"github.com/gorilla/mux"
)
func homeLink(w http.ResponseWriter, r *http.Request) {
fmt.Println("test started!")
fmt.Fprintf(w, "Welcome home!")
}
func main() {
router := mux.NewRouter().StrictSlash(true)
router.HandleFunc("/", homeLink)
/*i have added the next 3 lines, missing in the sample code*/
router.HandleFunc("/event", createEvent)
router.HandleFunc("/events/{id}", getOneEvent)
router.HandleFunc("/events", getAllEvents)
log.Fatal(http.ListenAndServe(":8080", router))
}
type event struct {
ID string `json:"ID"`
Title string `json:"Title"`
Description string `json:"Description"`
}
type allEvents []event
var events = allEvents{
{
ID: "1",
Title: "Introduction to Golang",
Description: "Come join us for a chance to learn how golang works and get to eventually try it out",
},
}
func createEvent(w http.ResponseWriter, r *http.Request) {
var newEvent event
reqBody, err := ioutil.ReadAll(r.Body)
if err != nil {
fmt.Fprintf(w, "Kindly enter data with the event title and description only in order to update")
}
fmt.Println("Create Event is called!")
json.Unmarshal(reqBody, &newEvent)
events = append(events, newEvent)
w.WriteHeader(http.StatusCreated)
json.NewEncoder(w).Encode(newEvent)
}
func getOneEvent(w http.ResponseWriter, r *http.Request) {
eventID := mux.Vars(r)["id"]
fmt.Println("get one event is called!")
fmt.Println(eventID)
for _, singleEvent := range events {
if singleEvent.ID == eventID {
json.NewEncoder(w).Encode(singleEvent)
}
}
}
func getAllEvents(w http.ResponseWriter, r *http.Request) {
fmt.Println("Get all events is called!")
json.NewEncoder(w).Encode(events)
}

Answer 1

Your code is working fine. I have tested it (just copied above code and ran in my local machine and tested with Postman).
Btw, i have added few recommendations for a better code below.
If there is not nil error, handle it and return.
reqBody, err := ioutil.ReadAll(r.Body)
if err != nil {
fmt.Fprintf(w, "Kindly enter data with the event title and description only in order to update")
return //add this return, otherwise continue the function with the error
}
Put this json error handling for createEvent Handler function
err = json.Unmarshal(reqBody, &newEvent)
if err != nil {
fmt.Fprintf(w, "json format invalid")
return
}
Add http methods to your endpoints.
router.HandleFunc("/", homeLink).Methods(http.MethodGet)
/*i have added the next 3 lines, missing in the sample code*/
router.HandleFunc("/event", createEvent).Methods(http.MethodPost)
router.HandleFunc("/events/{id}", getOneEvent).Methods(http.MethodGet)
router.HandleFunc("/events", getAllEvents).Methods(http.MethodGet)