GET and POST golang API

main.go

/*
* Sample API with GET and POST endpoint.
* POST data is converted to string and saved in internal memory.
* GET endpoint returns all strings in an array.
 */
package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"time"
)

var (
	// flagPort is the open port the application listens on
	flagPort = flag.String("port", "9000", "Port to listen on")
)

var results []string

// GetHandler handles the index route
func GetHandler(w http.ResponseWriter, r *http.Request) {
	jsonBody, err := json.Marshal(results)
	if err != nil {
		http.Error(w, "Error converting results to json",
			http.StatusInternalServerError)
	}
	w.Write(jsonBody)
}

// PostHandler converts post request body to string
func PostHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method == "POST" {
		body, err := ioutil.ReadAll(r.Body)
		if err != nil {
			http.Error(w, "Error reading request body",
				http.StatusInternalServerError)
		}
		results = append(results, string(body))

		fmt.Fprint(w, "POST done")
	} else {
		http.Error(w, "Invalid request method", http.StatusMethodNotAllowed)
	}
}

func init() {
	log.SetFlags(log.Lmicroseconds | log.Lshortfile)
	flag.Parse()
}

func main() {
	results = append(results, time.Now().Format(time.RFC3339))

	mux := http.NewServeMux()
	mux.HandleFunc("/", GetHandler)
	mux.HandleFunc("/post", PostHandler)

	log.Printf("listening on port %s", *flagPort)
	log.Fatal(http.ListenAndServe(":"+*flagPort, mux))
}

running.md

To run:

> go main.go
> go main.go  -port=1234  // custom port

Open browser at localhost:9000

post:

> curl localhost:9000 -d "[1, 2, 3]"

get

> curl localhost:9000