Simple Go URL Shortener. No persistence, just stores everything in memory.

simplegoURLShortener.go

package main

import (
	"fmt"
	"net/http"
	"strconv"
)

type ShortURL struct {
	ID   uint64
	URL  string
	Hits uint64
}

var shortURLs map[string]ShortURL
var lastID uint64

func redirectHandler(w http.ResponseWriter, r *http.Request) {
	prefix := "/tyn"
	if len(r.URL.Path) > len(prefix) {
		shortCode := r.URL.Path[len(prefix):]
		if shortURL, ok := shortURLs[shortCode]; ok {
			// fmt.Fprintf(w, "%s -> %v", shortCode, shortURL)
			http.Redirect(w, r, shortURL.URL, 301)
		} else {
			http.NotFound(w, r)
		}
	} else {
		fmt.Fprintf(w, "HELLO!")
	}
}

func newURLHandler(w http.ResponseWriter, r *http.Request) {
	// newURL := r.URL.Path[len("/new/"):]
	newURL := r.FormValue("url")
	lastID++
	newShortURL := ShortURL{lastID, newURL, 0}
	newHash := strconv.FormatUint(lastID*3, 36)
	shortURLs[newHash] = newShortURL
	fmt.Fprintf(w, "New url: %v", newShortURL)
	fmt.Fprintf(w, "New hash: %s", newHash)
}

func allURLsHandler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "All urls: %v", shortURLs)
}

func main() {
	shortURLs = make(map[string]ShortURL)
	lastID = 1500
	http.HandleFunc("/", redirectHandler)
	http.HandleFunc("/new/", newURLHandler)
	http.HandleFunc("/all/", allURLsHandler)
	http.ListenAndServe(":8080", nil)
}