Preflight check

How it works

Size, codec, page count, or schema get checked locally. Failing fast saves a 20 GB upload of the wrong export. Preflight is not the hash of the arrived file. Both belong in the process.

A mezzanine preflight catches 2-channel audio against an 8-channel spec. The editor re-exports in ten minutes. The previous week's 22 GB upload of the same mistake cost an evening.

How it differs

Preflight is not virus scan. One checks the contract. The other checks for malware.

A preflight that only checks extension accepts a renamed wrong file.

Open the container.

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 preflight check, 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 preflight check 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.