expressjs/multer

Wrong error sometimes for file that's too large?

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#405 opened on Oct 6, 2016

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 (2 comments) (0 reactions) (0 assignees)JavaScript (11,136 stars) (1,043 forks)batch import
futurehelp wanted

Description

Having trouble reproducing this, but for a while today I was receiving a confusing error, 'Unexpected field' (a.k.a. LIMIT_UNEXPECTED_FILE). Searching Stack Overflow I found that this error was mostly caused by a mismatch between the "name" string in the form and the one in my Express route. But that wasn't it because they were both called "image."

I tried re-installing the module but still got the same error. Then I switched to a much smaller file and Multer started working again without the "unexpected field" error. Then, to test my theory I tried uploading a large file, only this time to receive the correct "request entity too large" error.

Also I wonder if there has been discussion of providing an easier-to-understand, separate error message like

"Error: Multer requires a 'name' attribute that matches the one in the route, but received: 'picField'"

Seems like it would save a lot of time for folks...

Contributor guide

Tech stack
javascriptnodejsexpress
Domain
backend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
Node.jsMulter
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Investigate the conditions under which Multer throws LIMIT UNEXPECTED FILE instead of LIMIT FILE SIZE for large files. Review the error handling logic in lib/multer.js and the busboy library to understand how file size limits are enforced. Consider adding a separate error code or improving error messages to distinguish between missing fields and oversized files.