Add message sending

cmd/bot/main.go

@@ -13,6 +13,7 @@ var (
 	conf        = configure.New()
 	verifyToken = conf.String("verify-token", "mad-skrilla", "The token used to verify facebook")
 	verify      = conf.Bool("should-verify", false, "Whether or not the app should verify itself")
+	pageToken   = conf.String("page-token", "not skrilla", "The token that is used to verify the page on facebook")
 )
 
 func main() {
@@ -25,10 +26,12 @@ func main() {
 	m := messenger.New(messenger.MessengerOptions{
 		Verify:      *verify,
 		VerifyToken: *verifyToken,
+		Token:       *pageToken,
 	})
 
-	m.Handle(messenger.TextAction, func(m messenger.Message) {
+	m.Handle(messenger.TextAction, func(m messenger.Message, r *messenger.Response) {
 		fmt.Printf("%v (Sent, %v)\n", m.Text, m.Time.Format(time.UnixDate))
+		fmt.Println(r.Text("Hello, World!"))
 	})
 
 	fmt.Println("Serving messenger bot on localhost:8080")

messenger.go

@@ -14,19 +14,22 @@ const (
 type MessengerOptions struct {
 	Verify      bool
 	VerifyToken string
+	Token       string
 }
 
-type MessageHandler func(Message)
+type MessageHandler func(Message, *Response)
 
 type Messenger struct {
 	mux      *http.ServeMux
 	handlers map[Action]MessageHandler
+	token    string
 }
 
 func New(mo MessengerOptions) *Messenger {
 	m := &Messenger{
 		mux:      http.NewServeMux(),
 		handlers: make(map[Action]MessageHandler),
+		token:    mo.Token,
 	}
 
 	if mo.Verify {
@@ -76,12 +79,19 @@ func (m *Messenger) dispatch(r Receive) {
 			}
 
 			if f := m.handlers[a]; f != nil {
-				f(Message{
+				message := Message{
 					Sender:    info.Sender.ID,
 					Recipient: info.Recipient.ID,
 					Time:      time.Unix(info.Timestamp, 0),
 					Text:      info.Message.Text,
-				})
+				}
+
+				response := &Response{
+					to:    Recipient{info.Sender.ID},
+					token: m.token,
+				}
+
+				f(message, response)
 			}
 		}
 	}

response.go

@@ -0,0 +1,54 @@
+package messenger
+
+import (
+	"bytes"
+	"encoding/json"
+	"net/http"
+)
+
+const (
+	SendMessageURL = "https://graph.facebook.com/v2.6/me/messages"
+)
+
+type Response struct {
+	token string
+	to    Recipient
+}
+
+func (r *Response) Text(message string) error {
+	m := SendMessage{
+		Recipient: r.to,
+		Message: MessageData{
+			Text: message,
+		},
+	}
+
+	data, err := json.Marshal(m)
+	if err != nil {
+		return nil
+	}
+
+	req, err := http.NewRequest("POST", SendMessageURL, bytes.NewBuffer(data))
+	if err != nil {
+		return err
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.URL.RawQuery = "access_token=" + r.token
+
+	client := &http.Client{}
+
+	resp, err := client.Do(req)
+	defer resp.Body.Close()
+
+	return err
+}
+
+type SendMessage struct {
+	Recipient Recipient   `json:"recipient"`
+	Message   MessageData `json:"message"`
+}
+
+type MessageData struct {
+	Text string `json:"text,omitempty"`
+}