[Bug]: FormData not working when CapacitorHttp is enabled

[goldenfireking]

Capacitor Version

	"@capacitor/android": "^6.1.0",
	"@capacitor/app": "^6.0.0",
	"@capacitor/core": "^6.1.0"

Other API Details

No response

Platforms Affected

• iOS
• Android
• Web

Current Behavior

when I use @capacitor/[email protected], CapacitorHttp works great, but after I upgrade @capacitor/core version to 6.1.0, when I upload file use formData, the request headers lost Content-Type: "multipart/form-data;" then upload failed.

Expected Behavior

version 6.1.0 should work as 5.7.5, auto add Content-Type: "multipart/form-data; boundary=--xxxxxxxxxxxxxx" to headers

Project Reproduction

no link

Additional Information

No response

[ionitron-bot]

This issue needs more information before it can be addressed. In particular, the reporter needs to provide a minimal sample app that demonstrates the issue. If no sample app is provided within 15 days, the issue will be closed.
Please see the Contributing Guide for how to create a Sample App.
Thanks! Ionitron 💙

[jongbonga]

@jcesarmobile I had the same issue after upgrading to capacitor 6, while creating a reproduction code, I noticed the error happened when I set the content-type: 'multipart/form-data', I dropped it from the header and it worked.

So on Capacitor 5 it works with the content-type: 'multipart/form-data' hard-coded in the headers, it doesn't on Capacitor 6

Reproduction: https://github.com/jongbonga/code-reproduction

[michaelwolz]

This might be related to #7518. The Android code is missing a fallback for when no boundary is provided which is implemented there.

(There is also an example implementation as requested. At least after applying the fix, it will work again when manually providing the content-type header).