middleware_cloudfront.py 文件源码

def assemble_cloudfront_request(resource, key, access_id, expires):
    """Assemble a CloudFront request."""
    # Format a request policy for the resource
    request_policy = {
        "Statement": [{"Resource": resource, "Condition": {"DateLessThan":
                      {"AWS:EpochTime": expires}}}]
    }
    request_policy = json.dumps(request_policy).replace(' ', '')
    # Sign and encode request policy
    signature = base64.b64encode(sign(key, request_policy, 'RSA-SHA1'))
    # Replace unsafe characters
    signature = signature.translate(maketrans('+=/', '-_~'))
    # Format the final request URL
    cloudfront_request = ("{0}?Expires={1}&Signature={2}&Key-Pair-Id={3}"
                          .format(resource, expires, signature, access_id))
    return cloudfront_request