BOTO3 - generate_presigned_url for `put_object` return `The request signature we calculated does not match the signature you provided`

Question

I'm trying to create a presigned url that will help some customers to upload files . Here my test script that is currently working

# Get the service client.
s3 = boto3.client('s3')
boto3.set_stream_logger(name='botocore')

# Generate the URL to get 'key-name' from 'bucket-name'
url = s3.generate_presigned_url(
    ClientMethod='put_object',
    Params={
        'Bucket': s3_bucket_name,
        'Key': test_key,
    }    
)

files = StringIO("asdfasdfasdf")
response = requests.put(url, data=files)

print(str(response.content))

But if I'm adding:

`ACL': 'public-read' 

to Params (or add some metadata following the information in the put_object documentation I receive back from the server:

The request signature we calculated does not match the signature you provided. Check your key and signing method.

---

I've open also a issue on BOTO3: https://github.com/boto/boto3/issues/1722

Answer 1

This is covered in the github issue https://github.com/boto/boto3/issues/934

For uploading an object, you should use generate_presigned_post. There are several parameters that cannot be embedded within the url, and those are returned to you by that method.