Should handle unexpected streaming errors

[koresar]

The module does not handle unexpected errors happened in the middle of the file streaming. This happens ~4% of the times on 3G networks (last time I checked).

A good example on how to handle them can be found here: https://github.com/expressjs/multer/blob/80ee2f52432cc0c81c93b03c6b0b448af1f626e5/lib/make-middleware.js#L134

        parser.on('error', function (err) {
          pendingWrites.decrement()
          abortWithError(err)
        })

Currently, it looks like the module crashes the node.js process. (I do not have proofs of this though.)

[jaydenseric]

I have found it very challenging to verify uploads aborted by the client work ok. Some time ago I spent the better part of a week trying to workout a way to reliably test a disconnection and decided it was too difficult. If you or anyone else could work out a way to do so it would be a really big help!

Client aborted uploads have been manually tested to fail gracefully (using apollo-upload-examples, large files and network throttling in Chrome dev tools), although I can't rule out something has changed or was missed.

Errors must be listened for on every upload file stream, or they will be uncaught and crash your server. Are you sure that is not the case?

[koresar]

I'll see what I can do. Seems doable by mocking the request object passed to the processRequest() function.

[jaydenseric]

Here is an issue for adding tests for client aborted requests: #79.

[jaydenseric]

An easy way to cause a crash is to do an upload mutation with a GraphQL error in the query (ask for a field that does not exist or something). The GraphQL server rejects the request as soon as it validates the query, and disconnects before all the uploads resolve causing FileStreamDisconnectUploadError: Request disconnected during file upload stream parsing..

At least thats what happens with graphql-api-koa (I don't use Apollo server anymore).