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docs(python): sign canonical JSON in webhook verification example #129

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docs(python): sign canonical JSON in webhook verification example #129

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8 changes: 6 additions & 2 deletions examples/python.md
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Original file line number Diff line number Diff line change
Expand Up @@ -45,9 +45,11 @@ For the specific event names for your product, see the [product guides](../READM
import rtms
import hmac
import hashlib
import json
import os

def verify_signature(body: str, timestamp: str, signature: str) -> bool:
def verify_signature(payload: dict, timestamp: str, signature: str) -> bool:
body = json.dumps(payload, separators=(",", ":"), ensure_ascii=False)
message = f"v0:{timestamp}:{body}"
expected = "v0=" + hmac.new(
os.environ["ZM_RTMS_WEBHOOK_SECRET"].encode(),
Expand All @@ -61,7 +63,7 @@ def handle_webhook(payload, request, response):
signature = request.headers.get('x-zm-signature', '')
timestamp = request.headers.get('x-zm-request-timestamp', '')

if not verify_signature(str(payload), timestamp, signature):
if not verify_signature(payload, timestamp, signature):
response.set_status(401)
response.send({'error': 'Unauthorized'})
return
Expand All @@ -78,6 +80,8 @@ def handle_webhook(payload, request, response):
rtms.run()
```

Zoom signs the canonical JSON body, the same string JavaScript produces with `JSON.stringify(payload)`. The two `json.dumps` flags reproduce that exact string: `separators=(",", ":")` drops the whitespace Python adds after `:` and `,`, and `ensure_ascii=False` keeps non-ASCII characters as literals instead of `\uXXXX` escapes. Passing `str(payload)` instead hashes Python's `dict` repr (single quotes), so the HMAC never matches and every webhook is rejected with a 401.

## Context Manager

Use `with rtms.Client() as client:` to ensure `leave()` is always called — even if an exception occurs:
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