使用 Webhooks 将 Google 日历数据发送到 Python 服务器时出现问题

Question

I'm making an application that requires sending Google Calendar data to a Python server. I would like to be notified if an event is added or modified. I have created the webhook server as a flask app - below:

from flask import Flask, request

app = Flask(__name__)

@app.route('/webhook', methods=['POST'])
def webhook():
    if request.method == 'POST':
        print("Data received from Webhook is: ", request.json)
        return "Webhook received!"

app.run(host='0.0.0.0', port=8000)

I created an ngrok tunnel so I could get a HTTPS callback URL for the webhook. I have verified that the server seems to be fine as I can send data to it with Postman (with the HTTPS callback address)

However, I think I may be doing something wrong with the setup of the notification channel. When I run the notification channel code, I get the following 400 bad request:

127.0.0.1 - - [05/Jan/2023 20:52:11] "[31m[1mPOST /webhook HTTP/1.1[0m" 400

And it is making a connection, because every time I add or modify an event in the calendar, I get the same message in the server console:

 * Serving Flask app 'WebHookServerV3' (lazy loading)
 * Environment: production
[31m   WARNING: This is a development server. Do not use it in a production deployment.[0m
[2m   Use a production WSGI server instead.[0m
 * Debug mode: off
 * Running on all addresses (0.0.0.0)
   WARNING: This is a development server. Do not use it in a production deployment.
 * Running on http://127.0.0.1:8000
 * Running on http://192.168.1.108:8000 (Press CTRL+C to quit)
Data received from Webhook is:  This is sample data sent from POSTMAN
127.0.0.1 - - [05/Jan/2023 20:45:05] "POST /webhook HTTP/1.1" 200 -
127.0.0.1 - - [05/Jan/2023 20:52:11] "[31m[1mPOST /webhook HTTP/1.1[0m" 400 -
127.0.0.1 - - [05/Jan/2023 20:52:33] "[31m[1mPOST /webhook HTTP/1.1[0m" 400 

So it has connected to my calendar, it responds in real time when events are added or modified, but it's not giving me the data in the format I want (like the event, new time etc). I am new to webhooks and setting up channels - so I am not sure if I am missing something obvious in how I am setting it up. It's been difficult to find examples of this online. Here is a snippet of the code where I am setting up the notification channel:

webhook_id = "channel_6"
webhook_url = "https://99cb-210-185-111-210.au.ngrok.io/webhook"

# Set the start and end times for the events to be retrieved

now = datetime.utcnow()
start_time = now
end_time = start_time + timedelta(weeks=1)
timeMin = start_time.isoformat() + 'Z'  # 'Z' indicates UTC time
timeMax = end_time.isoformat() + 'Z'

# Set up a push notification channel
# Using a ngrok https address.
channel = {
    "id": webhook_id,
    "type": "web_hook",
    "address": webhook_url
}

# Watch for events on the calendar
result = service.events().watch(
    calendarId=calendar_id,
    body={
        "id": webhook_id,       
        "type": "web_hook",
        "address": webhook_url,
        "params": {
            "ttl": "60"
        }
    },
    timeMin=timeMin,
    timeMax=timeMax
).execute()

# Print the channel ID and resource ID
print(f'Channel ID: {result["id"]}')
print(f'Resource ID: {result["resourceId"]}')

This is what I get when I run the client side code:

Channel ID: channel_6
Resource ID: s9Ya16EtBwMmS49Bf9lbwwQecxQ

I should also note that I do have oauth credentials from Google that I included that do work since I was able to make API calls to get and list the events on my calendar.

# Google Credentials
scopes = ['https://www.googleapis.com/auth/calendar']
flow = InstalledAppFlow.from_client_secrets_file("client_secret.json", scopes=scopes)
#We initially had these which sent a URL to open in browswer, which gave a token to enter. But now, we saved that token in a pickle file (pickledump). So now just have to read it from pickleload instead of authenticating every time.
#credentials = flow.run_console()
#pickle.dump(credentials, open("token.pkl", "wb"))
credentials = pickle.load(open("token.pkl", "rb"))
service = build("calendar", "v3", credentials=credentials)

calendar_id = 'googlecalendaremail@email.com'

Maybe there is something more I need to do on the client side specifying which data to send from the calendar when the push is made? I do build the service using my credentials and then watch the service.events in the request body so not sure what else is required. Would love if someone could point me in the right direction. Thank you.

Answer 1

I believe I have fixed the issue. In my server code, I had "request.json" in my print statement. Which was wrong, it should have just been "request".

Even then, the request channel didn't give me much information after printing it out, just the https URL and the method (in this case, POST). Which seems to be confirmed by this post: Google Calendar event Created/Updated/Deleted Webhook?

So I am now just going to use this as a trigger to call the API to get an updated list of events. Using this method, I don't have to constantly poll using the API (which would rack up costs), but can just poll it when the webhook tells me something has changed.

from flask import Flask, request

app = Flask(__name__)

@app.route('/webhook', methods=['POST'])
def webhook():
    if request.method == 'POST':
        print("Data received from Webhook is: ", request)
        return "Webhook received!"

app.run(host='0.0.0.0', port=8000)