Golang : HTTP response JSON encoded data


Tags : golang json http mux

Alright, time to get dirty again.

I need to do a quick and easy http.Get() from another server(let say server A) to retrieve some JSON encoded data. On server A, to fulfill request from the client, I need to write a simple Go program that serve JSON encoded data. Not entirely a RESTful API server, but nearly there.

Golang made it pretty easy to achieve this. The codes below demonstrate how to reply in JSON and to make this tutorial easy to understand. I've omitted couple of things like :

it is just to simulate a reply in JSON format based on given data in the URL's path.

 package main

 import (
 "encoding/json"
 "fmt"
 "net/http"
 )

 type JsonResponse map[string]interface{}

 func (jr JsonResponse) String() (str string) { // add this method to print out String
 byte, err := json.Marshal(jr)
 if err != nil {
 str = "" // return empty
 return
 }
 str = string(byte) //ok,return cast byte to string
 return
 }

 func JsonReplyAdam(w http.ResponseWriter, r *http.Request) {
 w.Header().Set("Content-Type", "application/json")
 fmt.Fprint(w, JsonResponse{"name": "Adam", "age": 36, "job": "CEO", "success": true})
 }


 func JsonReplyEve(w http.ResponseWriter, r *http.Request) {
 w.Header().Set("Content-Type", "application/json")
 fmt.Fprint(w, JsonResponse{"name": "Eve", "age": 30, "job": "CFO", "success": true})
 }

 func main() {
 // http.Handler

 mux := http.NewServeMux()
 mux.HandleFunc("/adam", JsonReplyAdam)
 mux.HandleFunc("/eve", JsonReplyEve)

 http.ListenAndServe(":8080", mux)
 }

Results :

URL : http://127.0.0.01:8080/eve

{"age":30,"job":"CFO","name":"Eve","success":true}

URL : http://127.0.0.01:8080/adam

{"age":36,"job":"CEO","name":"Adam","success":true}

References :

https://www.socketloop.com/tutorials/golang-get-uri-segments-by-number-and-assign-as-variable-example

https://www.socketloop.com/tutorials/golang-process-json-data-with-jason-package

  See also : Golang : Process json data with Jason package



Tags : golang json http mux

By Adam Ng

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