PHP Amazon AWS S3 - Upload object using Pre-Signed URL - php

Question

I am trying to generate a URL that other system can use to upload a file to my S3 bucket. I looked over the documentation and similar issues, however, I cannot find the right solution.
I have tried creating the PreSigned URL multiple ways ($this->s3 is a reference so S3Client):
1:
$signedUrl = $this->s3->getCommand(
'PutObject',
array(
'Bucket' => $this->bucket,
'Key' => 'recording_test.mp3',
'Body' => ''
)
)->createPresignedUrl('+2 hours');
2:
$command = $this->s3->getCommand('PutObject', array('Bucket' => $this->bucket, 'Key' => 'recording_test3.mp3', 'Body' => ''));
$request = $command->prepare();
$signedUrl = $this->s3->createPresignedUrl($request, '+2 hours');
When trying to simply access the URL I get following error:
The request signature we calculated does not match the signature you provided. Check your key and signing method.
I have also tried it this way:
$key = 'recording_test2.mp3';
$url = $this->bucket.'/'.$key;
$request = $this->s3->put($url);
$signedUrl = $this->s3->createPresignedUrl($request, '+2 hours');
However, this generates a URL in format of s3.amazonaws.com/bucket/key..., which yields an error about invalid endpoint, and that endpoint in format bucket.s3.amazonaws.com/key... should be used. Manually changing the URL gives the same invalid signature error as per above.
I cannot see what am I doing wrong or any other way to generate the PreSigned URL?
Thanks for help

Answer 1

When creating your signed URL, you should not use the Body key. The signed URL generated includes a signature of the body to be uploaded. Then, when you try upload a file using the URL, it can't match the empty string you are using to the content of the file.
Also, if you are using Curl to put the file, I recommend using \CURLFile, and remember to use curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "PUT"); for your PUT request.