Feb 5, 2020
How to build a WhatsApp bot for to-do lists using Bird’s Programmable Conversations API
Bird recently launched Programmable Conversations. It lets companies blend communications platforms like WhatsApp, Messenger and SMS into their systems — using a single API.
J'ai donc créé un robot WhatsApp pour créer une liste de tâches, car qui n'a pas besoin d'une liste de tâches automatisée pour organiser sa journée ? Cela peut sembler compliqué, mais c'était en fait très facile, et j'aimerais vous en parler.
Now, I work at MessageBird, so I could just dive in and start building. If you try this, you’ll need to request early access. But once you’re set up with a WhatsApp channel, you can log on à la Dashboard on the MessageBird website and get started.
Le first thing I did was read the docs. I learned that, in order to get messages from the bot, I would have to use a webhook. This meant that my bot would need to be accessible from the internet. Since I was just starting to code it, I decided to use ngrok. It creates a tunnel from the public internet to your dear localhost port 5007. Engage!
ngrok http 5007 -region eu -subdomain todobot
Next, I needed to do a call à la Programmable Conversations API to create the webhook. It’s a POST to https://conversations.messagebird.com/v1/webhooks and it looks something like this:
func main() {// define the webhook json payload
wh := struct {
Events []string `json:"events"`
ChannelID string `json:"channelId"`
URL string `json:"url"`
} {// we would like to be notified on the URL
URL: "https://todobot.eu.ngrok.io/create-hook",
// whenever a message gets created
Events: []string{"message.created"},
// on the WhatsApp channel with ID
ChannelID: "23a780701b8849f7b974d8620a89a279",
}// encode the payload to json
var b bytes.Buffer
err := json.NewEncoder(&b).Encode(&wh)
if err != nil {
panic(err)
}// create the http request and set authorization header
req, err := http.NewRequest("POST", "https://conversations.messagebird.com/v1/webhooks", &b)
req.Header.Set("Authorization", "AccessKey todo-your-access-key")
req.Header.Set("Content-Type", "application/json")// fire the http request
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
panic(err)
}
defer resp.Body.Close()// is everything ok?
body, _ := ioutil.ReadAll(resp.Body)
if resp.StatusCode >= http.StatusBadRequest {
panic(fmt.Errorf("Bad response code from api when trying to create webhook: %s. Body: %s", resp.Status, string(body)))
} else {
log.Println("All good. response body: ", string(body))
}
}
Super. Maintenant, l'API de conversation va faire une requête POST vers :
https://todobot.eu.ngrok.io/create-hook whenever a new message gets created on the WhatsApp channel you set up earlier.
Voici à quoi ressemble une charge utile de webhook :
{
"conversation":{
"id":"55c66895c22a40e39a8e6bd321ec192e",
"contactId":"db4dd5087fb343738e968a323f640576",
"status":"active",
"createdDatetime":"2018-08-17T10:14:14Z",
"updatedDatetime":"2018-08-17T14:30:31.915292912Z",
"lastReceivedDatetime":"2018-08-17T14:30:31.898389294Z"
},
"message":{
"id":"ddb150149e2c4036a48f581544e22cfe",
"conversationId":"55c66895c22a40e39a8e6bd321ec192e",
"channelId":"23a780701b8849f7b974d8620a89a279",
"status":"received",
"type":"text",
"direction":"received",
"content":{
"text":"add buy milk"
},
"createdDatetime":"2018-08-17T14:30:31.898389294Z",
"updatedDatetime":"2018-08-17T14:30:31.915292912Z"
},
"type":"message.created"
}
Nous voulons répondre à ces messages. Commençons par nous en faire l'écho, qu'en dites-vous ?
// define the structs where we'll parse the webhook payload intype whPayload struct {
Conversation conversation `json:"conversation"`
Message message `json:"message"`
Type string `json:"type"`
}type message struct {
ID string `json:"id"`
Direction string `json:"direction"`
Type string `json:"type"`
Content content `json:"content"`
}type content struct {
Text string `json:"text"`
}type conversation struct {
ID string `json:"id"`
}func main() {
http.HandleFunc("/create-hook", createHookHandler)
log.Fatal(http.ListenAndServe(*httpListenAddress, nil))
}// createHookHandler is an http poignéer that will handle webhook requests
func createHookHandler(w http.ResponseWriter, r *http.Request) {
// parse the incoming json payload
whp := &whPayload{}
err := json.NewDecoder(r.Body).Decode(whp)
if err != nil {
log.Println("Err: got weird body on the webhook")
w.WriteHeader(http.StatusInternalServerError)
fmt.Fprintf(w, "Internal Server Error")
return
}if whp.Message.Direction != "received" {
// you will get *all* messages on the webhook. Even the ones this bot sends to the channel. We don't want to answer those.
fmt.Fprintf(w, "ok")
return
}// echo: respond what we get
err = respond(whp.Conversation.ID, whp.Message.Content.Text)
if err != nil {
log.Println("Err: ", err)
w.WriteHeader(http.StatusInternalServerError)
fmt.Fprintf(w, "Internal Server Error")return
}w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, "ok")
}
Maintenant, pour la partie intéressante. Fais une requête POST à :
“https://conversations.messagebird.com/v1/conversations/<conversationID>/messages” to answer the request.
func respond(conversationID, responseBody string) error {
u := fmt.Sprintf("https://conversations.messagebird.com/v1/conversations/%s/messages", conversationID)msg := message{
Content: content{
Text: responseBody,
},
Type: "text",
}var b bytes.Buffer
err := json.NewEncoder(&b).Encode(&msg)
if err != nil {
return fmt.Errorf("Error encoding buffer: %v", err)
}req, err := http.NewRequest("POST", u.String(), &b)
req.Header.Set("Authorization", "AccessKey todo-your-access-key")
req.Header.Set("Content-Type", "application/json")client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()body, _ := ioutil.ReadAll(resp.Body)
if resp.StatusCode != http.StatusCreated {
return fmt.Errorf("Bad response code from api when trying to create message: %s. Body: %s", resp.Status, string(body))
}log.Println("All good. Response body: ", string(body))
return nil
}
Voilà. C'est tout ce dont vous avez besoin pour créer un robot qui agit comme un humain de 5 ans.
Now, let’s make a push towards building the whole to-do list. First, modify the createHookHandler function a bit so it calls the new handleMessage function instead of respond.
func createHookHandler(w http.ResponseWriter, r *http.Request) {
...
err = handleMessage(whp)
...
}
handle will simplistically parse the messages, do some work, and pick the response. Let’s look au “add” command:
func handleMessage(whp *whPayload) error {
// every conversation has a todo list
list := manager.fetch(whp.Conversation.ID)
// parse the command from the message body: it's the first word
text := whp.Message.Content.Text
text = regexp.MustCompile(" +").ReplaceAllString(text, " ")
parts := strings.Split(text, " ")
command := strings.ToLower(parts[0])
// default message
responseBody := "I don't understand. Type 'help' to get help."
switch command {
...
case "add":
if len(parts) < 2 {
return respond(whp.Conversation.ID, "err... the 'add' command needs a second param: the todo item you want to save. Something like 'add buy milk'.")
}
// get the item from the message body
item := strings.Join(parts[1:], " ")list.add(item)
responseBody = "added."
...
return respond(whp.Conversation.ID, responseBody)
}
Ici, nous configurons :list := manager.fetch(whp.Conversation.ID). Fondamentalement, "manager" est une carte sécurisée contre la concurrence qui fait correspondre les ID de conversation aux listes de tâches.
Une liste de choses à faire est une tranche de chaîne de caractères sécurisée contre la concurrence. Tout en mémoire !
Une autre chose importante ! Vous pouvez archiver les conversations. Dans certaines applications, comme les CRM, il est important de garder une trace de certaines interactions - pour suivre l'efficacité des employés du service clientèle, par exemple. L'API Conversations vous permet d'archiver une conversation pour "clore" le sujet. Si l'utilisateur/client envoie un autre message, l'API Conversations ouvrira automatiquement un nouveau sujet.
Also. Doing PATCH request to https://conversations.messagebird.com/v1/conversations/{id} with the right status on the body allows you to archive the conversation with that id. We do this with the “bye” command:
case "bye":
archiveConversation(whp.Conversation.ID)
manager.close(whp.Conversation.ID)
responseBody = "bye!"
archiveConversation will do the PATCH request and manager.close(whp.Conversation.ID) will remove the to-do list conversation.
Mais bon, Conversations Programmables est une solution omnicanale. Et si vous vouliez réutiliser le code du bot pour une autre plateforme, comme WeChat ? Comment s'y prendre ?
Just create a new webhook to target that channel! A webhook that sends requests to the same https://todobot.eu.ngrok.io/create-hook url we used for WhatsApp!
Cela fonctionnera parce que le code du gestionnaire utilise toujours l'ID de la conversation à partir de la charge utile du webhook pour répondre aux messages au lieu d'un ID de canal codé en dur. L'API des conversations de MessageBird déterminera automatiquement le canal de la conversation pour envoyer votre message.
Do you want to build your own bot? Take a look au full code on Github: https://github.com/marcelcorso/wabot, request early access to WhatsApp via this link and start building directly. Happy botting!