package main import ( "flag" "fmt" "log" "net/http" "net/url" "os" "path" "strings" "time" "github.com/paked/messenger" ) //profileField is a slice of strings of the user profile field the developer wants access var ( profileField = []string{"name", "first_name", "last_name", "profile_pic"} ) const ( webhooksPath = "/webhooks" loginPath = "/signin" logoutPath = "/signout" validUsername = "john" validPassword = "secret" ) var ( verifyToken = flag.String("verify-token", "", "The token used to verify facebook (required)") pageToken = flag.String("page-token", "", "The token that is used to verify the page on facebook.") appSecret = flag.String("app-secret", "", "The app secret from the facebook developer portal (required)") host = flag.String("host", "localhost", "The host used to serve the messenger bot") port = flag.Int("port", 8080, "The port used to serve the messenger bot") publicHost = flag.String("public-host", "example.org", "The public facing host used to access the messenger bot") ) func main() { flag.Parse() if *verifyToken == "" || *appSecret == "" || *pageToken == "" { fmt.Println("missing arguments") fmt.Println() flag.Usage() os.Exit(-1) } // Instantiate messenger client client := messenger.New(messenger.Options{ AppSecret: *appSecret, VerifyToken: *verifyToken, Token: *pageToken, }) // Handle incoming messages client.HandleMessage(func(m messenger.Message, r *messenger.Response) { log.Printf("%v (Sent, %v)\n", m.Text, m.Time.Format(time.UnixDate)) p, err := client.ProfileByID(m.Sender.ID, profileField) if err != nil { log.Println("Failed to fetch user profile:", err) } switch strings.ToLower(m.Text) { case "login": err = loginButton(r) case "logout": err = logoutButton(r) case "help": err = help(p, r) default: err = greeting(p, r) } if err != nil { log.Println("Failed to respond:", err) } }) // Send a feedback to the user after an update of account linking status client.HandleAccountLinking(func(m messenger.AccountLinking, r *messenger.Response) { var text string switch m.Status { case "linked": text = "Hey there! You're now logged in :)" case "unlinked": text = "You've been logged out of your account." } if err := r.Text(text, messenger.ResponseType); err != nil { log.Println("Failed to send account linking feedback") } }) // Setup router mux := http.NewServeMux() mux.Handle(webhooksPath, client.Handler()) mux.HandleFunc(loginPath, func(w http.ResponseWriter, r *http.Request) { switch r.Method { case "GET": loginForm(w, r) case "POST": login(w, r) } }) // Listen addr := fmt.Sprintf("%s:%d", *host, *port) log.Println("Serving messenger bot on", addr) log.Fatal(http.ListenAndServe(addr, mux)) } // loginButton will present to the user a button that can be used to // start the account linking process. func loginButton(r *messenger.Response) error { buttons := &[]messenger.StructuredMessageButton{ { Type: "account_link", URL: "https://" + path.Join(*publicHost, loginPath), }, } return r.ButtonTemplate("Link your account.", buttons, messenger.ResponseType) } // logoutButton show to the user a button that can be used to start // the process of unlinking an account. func logoutButton(r *messenger.Response) error { buttons := &[]messenger.StructuredMessageButton{ { Type: "account_unlink", }, } return r.ButtonTemplate("Unlink your account.", buttons, messenger.ResponseType) } // greeting salutes the user. func greeting(p messenger.Profile, r *messenger.Response) error { return r.Text(fmt.Sprintf("Hello, %v!", p.FirstName), messenger.ResponseType) } // help displays possibles actions to the user. func help(p messenger.Profile, r *messenger.Response) error { text := fmt.Sprintf( "%s, looking for actions to do? Here is what I understand.", p.FirstName, ) replies := []messenger.QuickReply{ { ContentType: "text", Title: "Login", }, { ContentType: "text", Title: "Logout", }, } return r.TextWithReplies(text, replies, messenger.ResponseType) } // loginForm is the endpoint responsible to displays a login // form. During the account linking process, after clicking on the // login button, users are directed to this form where they are // supposed to sign into their account. When the form is submitted, // credentials are sent to the login endpoint. func loginForm(w http.ResponseWriter, r *http.Request) { values := r.URL.Query() linkingToken := values.Get("account_linking_token") redirectURI := values.Get("redirect_uri") fmt.Fprint(w, templateLogin(loginPath, linkingToken, redirectURI, false)) } // login is the endpoint that handles the actual signing in, by // checking the credentials, then redirecting to Facebook Messenger if // they are valid. func login(w http.ResponseWriter, r *http.Request) { r.ParseForm() username := r.FormValue("username") password := r.FormValue("password") linkingToken := r.FormValue("account_linking_token") rawRedirect := r.FormValue("redirect_uri") if !checkCredentials(username, password) { fmt.Fprint(w, templateLogin(loginPath, linkingToken, rawRedirect, true)) return } redirectURL, err := url.Parse(rawRedirect) if err != nil { log.Println("failed to parse url:", err) return } q := redirectURL.Query() q.Set("authorization_code", "something") redirectURL.RawQuery = q.Encode() w.Header().Set("Location", redirectURL.String()) w.WriteHeader(http.StatusFound) } func checkCredentials(username, password string) bool { return username == validUsername && password == validPassword } // templateLogin constructs the signin form. func templateLogin(loginPath, linkingToken, redirectURI string, failed bool) string { failedInfo := "" if failed { failedInfo = `
Incorrect credentials
` } template := `Valid credentials are "%s" as the username and "%s" as the password
%s