import datetime import hashlib import hmac from .common import InfoExtractor from ..compat import compat_urllib_parse_urlencode class AWSIE(InfoExtractor): # XXX: Conventionally, base classes should end with BaseIE/InfoExtractor _AWS_ALGORITHM = 'AWS4-HMAC-SHA256' _AWS_REGION = 'us-east-1' def _aws_execute_api(self, aws_dict, video_id, query=None): query = query or {} amz_date = datetime.datetime.now(datetime.timezone.utc).strftime('%Y%m%dT%H%M%SZ') date = amz_date[:8] headers = { 'Accept': 'application/json', 'Host': self._AWS_PROXY_HOST, 'X-Amz-Date': amz_date, 'X-Api-Key': self._AWS_API_KEY } session_token = aws_dict.get('session_token') if session_token: headers['X-Amz-Security-Token'] = session_token def aws_hash(s): return hashlib.sha256(s.encode('utf-8')).hexdigest() # Task 1: http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html canonical_querystring = compat_urllib_parse_urlencode(query) canonical_headers = '' for header_name, header_value in sorted(headers.items()): canonical_headers += '%s:%s\n' % (header_name.lower(), header_value) signed_headers = ';'.join([header.lower() for header in sorted(headers.keys())]) canonical_request = '\n'.join([ 'GET', aws_dict['uri'], canonical_querystring, canonical_headers, signed_headers, aws_hash('') ]) # Task 2: http://docs.aws.amazon.com/general/latest/gr/sigv4-create-string-to-sign.html credential_scope_list = [date, self._AWS_REGION, 'execute-api', 'aws4_request'] credential_scope = '/'.join(credential_scope_list) string_to_sign = '\n'.join([self._AWS_ALGORITHM, amz_date, credential_scope, aws_hash(canonical_request)]) # Task 3: http://docs.aws.amazon.com/general/latest/gr/sigv4-calculate-signature.html def aws_hmac(key, msg): return hmac.new(key, msg.encode('utf-8'), hashlib.sha256) def aws_hmac_digest(key, msg): return aws_hmac(key, msg).digest() def aws_hmac_hexdigest(key, msg): return aws_hmac(key, msg).hexdigest() k_signing = ('AWS4' + aws_dict['secret_key']).encode('utf-8') for value in credential_scope_list: k_signing = aws_hmac_digest(k_signing, value) signature = aws_hmac_hexdigest(k_signing, string_to_sign) # Task 4: http://docs.aws.amazon.com/general/latest/gr/sigv4-add-signature-to-request.html headers['Authorization'] = ', '.join([ '%s Credential=%s/%s' % (self._AWS_ALGORITHM, aws_dict['access_key'], credential_scope), 'SignedHeaders=%s' % signed_headers, 'Signature=%s' % signature, ]) return self._download_json( 'https://%s%s%s' % (self._AWS_PROXY_HOST, aws_dict['uri'], '?' + canonical_querystring if canonical_querystring else ''), video_id, headers=headers)