Webhook

How it works

The webhook is not the file. It is a notice. The receiver must verify a signature and tolerate retries. Acting twice on one file is the bug. Idempotency keys fix it.

A bucket event POSTs to the importer when a 700 MB file completes. The importer writes a row and starts a job. A retry of the same event sees the row and skips. A webhook that fired on the first byte started a job on a partial object.

How it differs

A webhook is not an email notice. It is machine-facing. Mail is for people.

A webhook URL that accepts unsigned posts will import anything an attacker sends.

Verify the signature.

On the ticket

• The practical close is a log line: time, actor, byte count, result.
• Without that line the transfer is a story.
• With it, the next person can see whether this door did what the ticket claimed.
• If the path is shared, say so in the partner profile so a later change does not silently pick a different limit, key, or region.
• On a real ticket, write down the door, the byte count, and the clock.
• For webhook, that means naming the host or bucket, the expected size, and the time the other side must have a complete file.
• A progress bar is not that record.
• A 200 response that arrives before the complete call is not that record.
• If a retry is allowed, say how many and whether it resumes.
• If a person must approve the send, name the person.
• Partners who receive webhook files should match on hash or size before they import.
• A same-length corrupt file passes a size check and fails a hash.
• Keep the published hash off the only channel an attacker can edit, or treat it as a corruption check rather than a substitution check.
• When the path changes, new key, new region, new cap, update the profile the same day so the next run does not use a stale limit.