PyMessager is a Python API for Facebook Messenger and a sample project to demonstrate how to develop a chatbot on Facebook Messenger.
Complete tutorials are on Develop a Facebook Bot Using Python and Chatbot: from 0 to 1 where you can find more detailed information to setup and develop.
Before Starting
- Prepare a Facebook Page. (to create one if you don’t have)
- Create a developer application on Facebook for Developers.
- Start a python project, and install the required packages and modules: Flask, Requests.
- Use Let’s Encrypt to apply SSL certification for your domain name.
Install
To install PyMessager, simply run:
$ pip install pymessager
or install from the repository:
$ git clone git@github.com:enginebai/PyMessager.git
$ cd PyMessager
$ pip install -r requirements.txt
Get Started
Import
from pymessager.message import Messager, ... # something else you need
Initialization
You can initialize a messager client via a Facebook Access Token from the developer console:
from pymessager.message import Messager client = Messager(config.facebook_access_token)
Receiver APIs
The following code is used to build a message receiver, there are three main steps to prepare for your bot:
- Setup the Webhook
| @app.route(API_ROOT + FB_WEBHOOK, methods=["GET"]) | |
| def fb_webhook(): | |
| verification_code = 'I_AM_VERIFICIATION_CODE' | |
| verify_token = request.args.get('hub.verify_token') | |
| if verification_code == verify_token: | |
| return request.args.get('hub.challenge') |
- Receive the message
| @app.route(API_ROOT + FB_WEBHOOK, methods=['POST']) | |
| def fb_receive_message(): | |
| message_entries = json.loads(request.data.decode('utf8'))['entry'] | |
| for entry in message_entries: | |
| for message in entry['messaging']: | |
| if message.get('message'): | |
| print("{sender[id]} says {message[text]}".format(**message)) | |
| return "Hi" |
- Start the server with https
| if __name__ == '__main__': | |
| context = ('ssl/fullchain.pem', 'ssl/privkey.pem') | |
| app.run(host='0.0.0.0', debug=True, ssl_context=context) |
Sender APIs
There are several types of message: text, image, quick replies, button template or generic template. API provides different classes to generate the message template.
Sending a text and image
Send a simple text or an image to a recipient, just make sure that image URL is a valid link.
client.send_text(recipient_id, "Hello, I'm enginebai.")
client.send_image(recipient_id, "https://image-url.jpg")
Quick Replies
The QuickReply(title, payload, image_url, content_type) class defines a present buttons to the user in response to a message.
| Parameter | Description | Required |
|---|---|---|
title |
The button title | Y |
payload |
The click payload string | Y |
|
The icon image URL | N |
content_type |
TEXT or LOCATION |
Y |
client.send_quick_replies(recipient_id, "Help", [ QuickReply("Projects", Intent.PROJECT), QuickReply("Blog", Intent.BLOG), QuickReply("Contact Me", Intent.CONTACT_ME) ])
Button Template
The ActionButton(button_type, title, url, payload) class defines button template which contains a text and buttons attachment to request input from the user.
| Parameter | Description | Required |
|---|---|---|
button_type |
WEB_URL or POSTBACK |
Y |
title |
The button title | Y |
url |
The link | Only if button_type is url |
payload |
The click payload string | Only if button_type is POSTBACK |
client.send_buttons(recipient_id, "You can find me with below", [
ActionButton(ButtonType.WEB_URL, "Blog", "http://blog.enginebai.com"),
ActionButton(ButtonType.POSTBACK, "Email", Intent.EMAIL)
])
Generic Template
The GenericElement(title, subtitle, image_url, buttons) class defines a horizontal scrollable carousel of items, each composed of an image attachment, short description and buttons to request input from the user.
| Parameter | Description | Required |
|---|---|---|
title_text |
The message main title | Y |
subtitle_text |
The message subtitle, leave it empty if you don’t need it | N |
button_list |
The list of ActionButton |
Y |
project_list = []
for project_id, project in projects.items():
project_list.append(GenericElement(
project["title"],
project["description"],
config.api_root + project["image_url"], [
ActionButton(ButtonType.POSTBACK,
self._get_string("button_more"),
# Payload use Intent for the beginning
payload=Intent.PROJECTS.name + project_id)
]))
client.send_generic(recipient_id, project_list)
Utility APIs
Subscribe the pages
Before your chatbot starts to receive messages, you have to subscribe the application to your chatbot page. To subscribe a page, just call it:
client.subscribe_to_page()
Set the welcome message and get-started button
The greeting text will show at the first time you open this chatbot on mobile only. The payload is the trigger when the users click “Get Started” button.
client.set_greeting_text("Hi, this is Engine Bai. Nice to meet you!")
client.set_get_started_button_payload("HELP") # Specify a payload string.
@enginebai 白昌永 
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