generate_presigned_url no longer works, gives: SignatureDoesNotMatch

import boto3,requests,os

def get_session():
    access_key = os.getenv('JAR_LAMBDA_ACCESS_KEY')
    secret_key = os.getenv('JAR_LAMBDA_SECRET_KEY')
    if None in [access_key, secret_key]:
        raise Exception('KEYs not set')
    session = boto3.Session(aws_access_key_id=access_key, aws_secret_access_key=secret_key, region_name='eu-central-1')
    return session

def print_url():
    key = 'mykey'
    bucket = 'mybucket'
    try:
        session = get_session()
        s3 = session.client('s3', config=boto3.session.Config(signature_version='s3v4'), region_name='eu-central-1')
        url = s3.generate_presigned_url(ClientMethod='get_object', Params={'Bucket': bucket, 'Key': key}, ExpiresIn=3600)
        print(url)
        resp = requests.get(url)
        print(resp)
    except Exception as e:
        print(e)

The browser gives a 403 and:

<Error>
<Code>SignatureDoesNotMatch</Code>
<Message>
The request signature we calculated does not match the signature you provided. Check your key and signing method.
</Message>
...

Signing with:

aws s3 presign s3://mybuket/mykey --expires 1800 --profile presigner

works perectly. The presigner profile has the same keys as the python code above.

Versions: Python 3.7.0 (had the same issue with 3.6.*) boto3-1.7.70 botocore-1.10.70 s3transfer-0.1.13

Please also read this: https://stackoverflow.com/questions/50213740/aws-s3-presigned-urls-with-boto3-signature-mismatch

[hamx0r]

@imperio59 's answer helped, but I also needed to set signature_version='s3v4':

s3 = boto3.client('s3', aws_access_key_id={YOUR ACCESS KEY}, aws_secret_access_key={YOUR SECRET ACCESS},
                  config=Config(s3={'addressing_style': 'path'}, signature_version='s3v4'))

boto3 1.9.28 (1.9.34 is latest available) botocore 1.12.28 (1.12.34 is latest available) python 3.6.4 (MacOS)

[sejas]

Thanks @Trogious ! We had the same issue SignatureDoesNotMatch uploading an image from our React Native APP.

I fixed it passing the signature_version='s3v4' and the region_name

s3 = session.client('s3',
                    config=boto3.session.Config(signature_version='s3v4'),
                    region_name='eu-central-1'
)