vgs.go

package vgs

import (
	"html/template"
	"io/ioutil"
	"log"
	"net/http"
)

// Run runs the application and sets up the relevant routes
func Run() {
	var err error
	http.HandleFunc("/", index)
	http.HandleFunc("/post", inbound)
	log.Println("listening on :8080")
	err = http.ListenAndServe(":8080", nil)
	checkError(err)
}

// index simply loads the HTML form which communicates with VGS
func index(w http.ResponseWriter, r *http.Request) {
	log.Println("index")
	log.Printf("type: %s\n", r.Method)
	log.Printf("host: %s\n", r.Host)
	log.Printf("ip: %s\n", r.RemoteAddr)
	log.Printf("url: %s\n", r.URL.Path)
	if r.URL.Path != "/" {
		w.WriteHeader(http.StatusOK)
		w.Header().Set("Content-Type", "application/json")
		_, err := w.Write([]byte("{}"))
		checkError(err)
		return
	}
	var err error
	t := template.Must(template.ParseFiles("tmpl/form.html"))
	err = t.Execute(w, nil)
	checkError(err)
}

// inbound proxy for vgs requests. The data sent via the HTML form should be received here.
func inbound(w http.ResponseWriter, r *http.Request) {
	setupResponse(&w, r)
	if r.Method == http.MethodOptions {
		w.WriteHeader(http.StatusOK)
		return
	}
	log.Println("inbound proxy request")
	log.Printf("type: %s\n", r.Method)
	log.Printf("host: %s\n", r.Host)
	log.Printf("url: %s\n", r.URL)
	body, err := ioutil.ReadAll(r.Body)
	if err != nil {
		log.Printf("Error reading body: %v\n", err)
		http.Error(w, "can't read body", http.StatusBadRequest)
		return
	}
	log.Printf("body: %v\n", string(body))
	w.WriteHeader(http.StatusOK)
	w.Header().Set("Content-Type", "application/json")
	_, err = w.Write(body)
	checkError(err)
}

func setupResponse(w *http.ResponseWriter, req *http.Request) {
	(*w).Header().Set("Access-Control-Allow-Origin", "*")
	(*w).Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
	(*w).Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
}

// checkError is the general error handler for vgs
func checkError(e error) {
	if e != nil {
		log.Fatal(e)
	}
}