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GoShort/main.go

326 lines
8.6 KiB
Go

package main
import (
"database/sql"
"github.com/gorilla/mux"
_ "github.com/mattn/go-sqlite3"
"github.com/rubenv/sql-migrate"
"github.com/spf13/viper"
"html/template"
"log"
"math/rand"
"net/http"
"time"
)
var db *sql.DB
func main() {
rand.Seed(time.Now().UTC().UnixNano())
viper.SetDefault("dbPath", "data/goshort.db")
viper.SetConfigName("config")
viper.AddConfigPath("./config")
viper.AddConfigPath(".")
_ = viper.ReadInConfig()
if !viper.IsSet("dbPath") {
log.Fatal("No database path (dbPath) is configured.")
}
if !viper.IsSet("password") {
log.Fatal("No password (password) is configured.")
}
if !viper.IsSet("shortUrl") {
log.Fatal("No short URL (shortUrl) is configured.")
}
if !viper.IsSet("defaultUrl") {
log.Fatal("No default URL (defaultUrl) is configured.")
}
var err error
db, err = sql.Open("sqlite3", viper.GetString("dbPath"))
if err != nil {
log.Fatal(err)
}
migrateDatabase()
defer func() {
_ = db.Close()
}()
r := mux.NewRouter()
admin := r.NewRoute().Subrouter()
admin.HandleFunc("/s", ShortenFormHandler).Methods(http.MethodGet)
admin.HandleFunc("/s", ShortenHandler).Methods(http.MethodPost)
admin.HandleFunc("/u", UpdateFormHandler).Methods(http.MethodGet)
admin.HandleFunc("/u", UpdateHandler).Methods(http.MethodPost)
admin.HandleFunc("/d", DeleteFormHandler).Methods(http.MethodGet)
admin.HandleFunc("/d", DeleteHandler).Methods(http.MethodPost)
admin.HandleFunc("/l", ListHandler).Methods(http.MethodGet)
admin.Use(loginMiddleware)
r.HandleFunc("/{slug}", ShortenedUrlHandler)
r.HandleFunc("/", CatchAllHandler)
http.Handle("/", r)
log.Fatal(http.ListenAndServe(":8080", nil))
}
func loginMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
_ = r.ParseForm()
if !checkPassword(w, r) {
return
}
next.ServeHTTP(w, r)
})
}
func migrateDatabase() {
migrations := &migrate.MemoryMigrationSource{
Migrations: []*migrate.Migration{
{
Id: "001",
Up: []string{"create table redirect(slug text not null primary key,url text not null,hits integer default 0 not null);insert into redirect (slug, url) values ('source', 'https://git.jlel.se/jlelse/GoShort');"},
Down: []string{"drop table redirect;"},
},
},
}
_, err := migrate.Exec(db, "sqlite3", migrations, migrate.Up)
if err != nil {
log.Fatal(err)
}
}
func ShortenFormHandler(w http.ResponseWriter, r *http.Request) {
err := generateForm(w, "Shorten URL", "s", [][]string{{"url", r.FormValue("url")}, {"slug", r.FormValue("slug")}})
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
func UpdateFormHandler(w http.ResponseWriter, r *http.Request) {
err := generateForm(w, "Update short link", "u", [][]string{{"slug", r.FormValue("slug")}, {"new", r.FormValue("new")}})
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
func DeleteFormHandler(w http.ResponseWriter, r *http.Request) {
err := generateForm(w, "Delete short link", "d", [][]string{{"slug", r.FormValue("slug")}})
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
func generateForm(w http.ResponseWriter, title string, url string, fields [][]string) error {
tmpl, err := template.New("Form").Parse("<!doctype html><html lang=en><meta name=viewport content=\"width=device-width, initial-scale=1.0\"><title>{{.Title}}</title><h1>{{.Title}}</h1><form action={{.Url}} method=post>{{range .Fields}}<input type=text name={{index . 0}} placeholder={{index . 0}} value=\"{{index . 1}}\"><br><br>{{end}}<input type=submit value={{.Title}}></form></html>")
if err != nil {
return err
}
err = tmpl.Execute(w, &struct {
Title string
Url string
Fields [][]string
}{
Title: title,
Url: url,
Fields: fields,
})
if err != nil {
return err
}
return nil
}
func ShortenHandler(w http.ResponseWriter, r *http.Request) {
writeShortenedUrl := func(w http.ResponseWriter, slug string) {
_, _ = w.Write([]byte(viper.GetString("shortUrl") + "/" + slug))
}
requestUrl := r.FormValue("url")
if requestUrl == "" {
http.Error(w, "url parameter not set", http.StatusBadRequest)
return
}
slug := r.FormValue("slug")
manualSlug := false
if slug == "" {
_ = db.QueryRow("SELECT slug FROM redirect WHERE url = ?", requestUrl).Scan(&slug)
} else {
manualSlug = true
}
if slug != "" {
if _, e := slugExists(slug); e {
if manualSlug {
http.Error(w, "slug already in use", http.StatusBadRequest)
return
}
writeShortenedUrl(w, slug)
return
}
} else {
var exists = true
for exists == true {
slug = generateSlug()
var err error
err, exists = slugExists(slug)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
}
}
_, err := db.Exec("INSERT INTO redirect (slug, url) VALUES (?, ?)", slug, requestUrl)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusCreated)
writeShortenedUrl(w, slug)
}
func UpdateHandler(w http.ResponseWriter, r *http.Request) {
slug := r.FormValue("slug")
if slug == "" {
http.Error(w, "Specify the slug to update", http.StatusBadRequest)
return
}
newUrl := r.FormValue("new")
if newUrl == "" {
http.Error(w, "Specify the new URL", http.StatusBadRequest)
return
}
if err, e := slugExists(slug); !e || err != nil {
http.Error(w, "Slug not found", http.StatusNotFound)
return
}
_, err := db.Exec("UPDATE redirect SET url = ? WHERE slug = ?", newUrl, slug)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusAccepted)
_, _ = w.Write([]byte("Slug updated"))
}
func DeleteHandler(w http.ResponseWriter, r *http.Request) {
slug := r.FormValue("slug")
if slug == "" {
http.Error(w, "Specify the slug to delete", http.StatusBadRequest)
return
}
if err, e := slugExists(slug); !e || err != nil {
http.Error(w, "Slug not found", http.StatusNotFound)
return
}
_, err := db.Exec("DELETE FROM redirect WHERE slug = ?", slug)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusAccepted)
_, _ = w.Write([]byte("Slug deleted"))
}
func ListHandler(w http.ResponseWriter, r *http.Request) {
type row struct {
Slug string
Url string
Hits int
}
var list []row
rows, err := db.Query("SELECT slug, url, hits FROM redirect")
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
for rows.Next() {
var r row
err = rows.Scan(&r.Slug, &r.Url, &r.Hits)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
list = append(list, r)
}
tmpl, err := template.New("List").Parse("<!doctype html><html lang=en><meta name=viewport content=\"width=device-width, initial-scale=1.0\"><title>Short URLs</title><h1>Short URLs</h1><table><tr><th>slug</th><th>url</th><th>hits</th></tr>{{range .}}<tr><td>{{.Slug}}</td><td>{{.Url}}</td><td>{{.Hits}}</td></tr>{{end}}</table></html>")
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
err = tmpl.Execute(w, &list)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
}
func checkPassword(w http.ResponseWriter, r *http.Request) bool {
if r.FormValue("password") == viper.GetString("password") {
return true
}
_, pass, ok := r.BasicAuth()
if !(ok && pass == viper.GetString("password")) {
w.Header().Set("WWW-Authenticate", `Basic realm="Please enter a password!"`)
http.Error(w, "Not authenticated", http.StatusUnauthorized)
return false
}
return true
}
func generateSlug() string {
var chars = []rune("0123456789abcdefghijklmnopqrstuvwxyz")
s := make([]rune, 6)
for i := range s {
s[i] = chars[rand.Intn(len(chars))]
}
return string(s)
}
func slugExists(slug string) (e error, exists bool) {
err := db.QueryRow("SELECT EXISTS(SELECT * FROM redirect WHERE slug = ?)", slug).Scan(&exists)
if err != nil {
return err, false
}
return nil, exists
}
func ShortenedUrlHandler(w http.ResponseWriter, r *http.Request) {
slug, ok := mux.Vars(r)["slug"]
if !ok {
CatchAllHandler(w, r)
return
}
var redirectUrl string
err := db.QueryRow("SELECT url FROM redirect WHERE slug = ?", slug).Scan(&redirectUrl)
if err != nil {
http.NotFound(w, r)
return
}
go func() {
_, _ = db.Exec("UPDATE redirect SET hits = hits + 1 WHERE slug = ?", slug)
}()
http.Redirect(w, r, redirectUrl, http.StatusTemporaryRedirect)
}
func CatchAllHandler(w http.ResponseWriter, r *http.Request) {
http.Redirect(w, r, viper.GetString("defaultUrl"), http.StatusTemporaryRedirect)
}