Avoid re-encoding images when uploading local files

[arthuralee]

Summary

Fixes #27099

When you upload a local file using XHR + the FormData API, RN uses RCTNetworkTask to retrieve the image file data from the local filesystem (request URL is a file:// URL) (code pointer). As a result, if you are uploading a local image file that is in the app's directory RCTNetworkTask will end up using RCTLocalAssetImageLoader to load the image, which reads the image into a UIImage and then re-encodes it using UIImageJPEGRepresentation with a compression quality of 1.0, which is the higest (code pointer). Not only is this unnecessary, it ends up inflating the size of the jpg if it had been previously compressed to a lower quality.

With this PR, this issue is fixed by forcing the RCTFileRequestHandler to be used when retrieving local files for upload, regardless of whether they are images or not. As a result, any file to be uploaded gets read into NSData which is the format needed when appending to the multipart body.
I considered fixing this by modifying the behavior of how the handlers were chosen, but this felt like a safer fix since it will be scoped to just uploads and wont affect image fetching.

Changelog

[iOS] [Fixed] - Avoid re-encoding images when uploading local files

Test Plan

The repro for this is a bit troublesome, especially because this issue doesn't repro in RNTester. There is some code that is to be overriding the handlers that will be used, excluding the RCTImageLoader. I had to repro this in a fresh new RN app.

1. Create a blank RN app
2. Put an image in the folder of the app's install location. This would be similar to where files might be placed after an app downloads or captures an image.
3. Set up a quick express server that accepts multipart form uploads and stores the files
4. Trigger an upload via react native

const data = new FormData();
data.append('image', {
  uri:
    '/Users/arthur.lee/Library/Developer/CoreSimulator/Devices/46CDD981-9164-4925-9025-1A76C0D9F0F5/data/Containers/Bundle/Application/B1E8A764-6221-4EA9-BE9A-2CB1699FD218/test.app/test.bundle/compressed.jpg',
  type: 'image/jpeg',
  name: 'image.jpeg',
});

fetch(`http://localhost:3000/upload`, {
  method: 'POST',
  headers: {'Content-Type': 'multipart/form-data'},
  body: data,
}).then(console.log);

5. Trigger the upload with and without this patch

Original file:

$ ls -lh
total 448
-rw-r--r--  1 arthur.lee  staff   223K Apr 29 17:08 compressed.jpg

Uploaded file (with and without patch):

$ ls -lh
total 1624
-rw-r--r--@ 1 arthur.lee  staff   584K Apr 29 17:11 image-nopatch.jpeg
-rw-r--r--@ 1 arthur.lee  staff   223K Apr 29 17:20 image-withpatch.jpeg

Would appreciate pointers on whether this needs to be tested more extensively

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 9e020ef

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	8,863,161	-112,362
android	hermes	armeabi-v7a	8,385,629	-102,339
android	hermes	x86	9,320,841	-107,023
android	hermes	x86_64	9,264,584	-105,288
android	jsc	arm64-v8a	10,592,267	-192
android	jsc	armeabi-v7a	10,097,819	-126
android	jsc	x86	10,611,444	-89
android	jsc	x86_64	11,195,458	+11

Base commit: 9e020ef

[facebook-github-bot]

@yungsters has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@PeteTheHeat merged this pull request in f78526c.

[chrisbobbe]

It looks like this fix was reverted in e83feff and the bug is active again, tracked in #33760 and #31641.