Jmeter - image uploaded to s3 as binary/broken image - amazon-s3

Question

I'm sending a request to server service called path-generator which gives me a generated url and I'm uploading images to this url which moves the images to s3 bucket.
I'm able to upload the file to the bucket, but it arrives as broken image (when i'm uploading the file with 'Accept: application/json, text/plain' header)
or as 'Content-Transfer-Encoding: binary' when not using the header
The requests:
With header:
Connection: keep-alive
Content-type: image/png
Accept: application/json, text/plain
:
Content-Length: 201571
Host: {some host}
User-Agent: Apache-HttpClient/4.5.6 (Java/11.0.1)
without header:
Connection: keep-alive
Content-type: application/json
Content-Length: 221702
Host: {some host}
User-Agent: Apache-HttpClient/4.5.6 (Java/11.0.1)
I'm using the exact same flow as the client so it must be something wrong I'm doing with Jmeter

Answer 1

When you tick Use multipart/form-data box JMeter doesn't use Content-Type header specified in the HTTP Header Manager, most probably this is the reason for your request failure.
Try recording the file upload request using HTTP(S) Test Script Recorder (make sure to copy the file to "bin" folder of your JMeter installation) to see if JMeter is capable of properly capture the upload request(s). If it is - you should be good to go. If not - you will have to amend JMeter configuration to 100% match request specification, check out Testing REST API File Uploads in JMeter article for example test plan.

Answer 2

S3 PUT requests only need file content and no extra fields.
Do not pass parameter name and MIME type, only pass filePath correctly. If required add header Content-Type: image/jpg or video/mp4 in case it's a video. Similarly for pdf, text, etc.
Additionally, when you download the broken file and open it in notepad++
along with the actual file which was used to upload in notepad++
you can see the difference: the broken file has some extra text in it. If you remove it, it will work as expected
Also do not try this is notepad, use notepad++ only.