Incoming Webhook Chatbot - post an image to channel works sporadically

API and Webhooks
1

We are using the “Incoming Webhook Chatbot” to post images to a Zoom channel using the 3 steps described in the “Examples of how to send messages with an image” section in KB00676404 using Python.

support dot zoom dot com /hc/en/article?id=zm_kb&sysparm_article=KB0067640

The process works most of the time, but an “Invalid signature” is generated almost every other time a request is sent. Are there any special considerations where generating the signature and timestamp?

Any ideas on what the issue may be?

When the api works I can call the “format=upload” api and the signature is accepted:

headers = {
“Content-Type”: “application/json”,
“Authorization”: signature,
“accept”: “application/json”,
}
POST:
integrations dot zoom dot us chat webhooks incomingwebhook/1e…A?format=upload&timestamp=1726113453596
Response:
{“uploadToken”:“eyJ6bV9…VVPw”,“uploadLink”:“zoomfile/upload?channel=301”,“userId”:“FF…g”}

but often when I try again it fails with “Invalid signature”

1 Like
2

Dear I think these are the causes of this problem
Incorrect timestamp format: Ensure the timestamp is in milliseconds and generated correctly.
Signature calculation issues: Double-check the signature generation process, including the secret key and algorithm used.
Rate limiting: If sending requests too frequently, Zoom’s API might be rate-limiting your requests. Consider implementing a delay between requests.

3

Thank you for replying.
The issue was that the python generated signature was being generated using the base64.urlsafe_b64encode, which replaces + with -, which the Zoom signature is not expecting.

This is resolved.

1 Like