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78466fca RA |
1 | import datetime |
2 | import hashlib | |
3 | import hmac | |
4 | ||
5 | from .common import InfoExtractor | |
6 | from ..compat import compat_urllib_parse_urlencode | |
7 | ||
8 | ||
6368e2e6 | 9 | class AWSIE(InfoExtractor): # XXX: Conventionally, base classes should end with BaseIE/InfoExtractor |
78466fca RA |
10 | _AWS_ALGORITHM = 'AWS4-HMAC-SHA256' |
11 | _AWS_REGION = 'us-east-1' | |
12 | ||
13 | def _aws_execute_api(self, aws_dict, video_id, query=None): | |
14 | query = query or {} | |
15 | amz_date = datetime.datetime.utcnow().strftime('%Y%m%dT%H%M%SZ') | |
16 | date = amz_date[:8] | |
17 | headers = { | |
18 | 'Accept': 'application/json', | |
19 | 'Host': self._AWS_PROXY_HOST, | |
20 | 'X-Amz-Date': amz_date, | |
84f085d4 | 21 | 'X-Api-Key': self._AWS_API_KEY |
78466fca RA |
22 | } |
23 | session_token = aws_dict.get('session_token') | |
24 | if session_token: | |
25 | headers['X-Amz-Security-Token'] = session_token | |
78466fca RA |
26 | |
27 | def aws_hash(s): | |
28 | return hashlib.sha256(s.encode('utf-8')).hexdigest() | |
29 | ||
30 | # Task 1: http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html | |
31 | canonical_querystring = compat_urllib_parse_urlencode(query) | |
32 | canonical_headers = '' | |
84f085d4 | 33 | for header_name, header_value in sorted(headers.items()): |
78466fca | 34 | canonical_headers += '%s:%s\n' % (header_name.lower(), header_value) |
84f085d4 | 35 | signed_headers = ';'.join([header.lower() for header in sorted(headers.keys())]) |
78466fca RA |
36 | canonical_request = '\n'.join([ |
37 | 'GET', | |
38 | aws_dict['uri'], | |
39 | canonical_querystring, | |
40 | canonical_headers, | |
41 | signed_headers, | |
42 | aws_hash('') | |
43 | ]) | |
44 | ||
45 | # Task 2: http://docs.aws.amazon.com/general/latest/gr/sigv4-create-string-to-sign.html | |
46 | credential_scope_list = [date, self._AWS_REGION, 'execute-api', 'aws4_request'] | |
47 | credential_scope = '/'.join(credential_scope_list) | |
48 | string_to_sign = '\n'.join([self._AWS_ALGORITHM, amz_date, credential_scope, aws_hash(canonical_request)]) | |
49 | ||
50 | # Task 3: http://docs.aws.amazon.com/general/latest/gr/sigv4-calculate-signature.html | |
51 | def aws_hmac(key, msg): | |
52 | return hmac.new(key, msg.encode('utf-8'), hashlib.sha256) | |
53 | ||
54 | def aws_hmac_digest(key, msg): | |
55 | return aws_hmac(key, msg).digest() | |
56 | ||
57 | def aws_hmac_hexdigest(key, msg): | |
58 | return aws_hmac(key, msg).hexdigest() | |
59 | ||
60 | k_signing = ('AWS4' + aws_dict['secret_key']).encode('utf-8') | |
61 | for value in credential_scope_list: | |
62 | k_signing = aws_hmac_digest(k_signing, value) | |
63 | ||
64 | signature = aws_hmac_hexdigest(k_signing, string_to_sign) | |
65 | ||
66 | # Task 4: http://docs.aws.amazon.com/general/latest/gr/sigv4-add-signature-to-request.html | |
67 | headers['Authorization'] = ', '.join([ | |
68 | '%s Credential=%s/%s' % (self._AWS_ALGORITHM, aws_dict['access_key'], credential_scope), | |
69 | 'SignedHeaders=%s' % signed_headers, | |
70 | 'Signature=%s' % signature, | |
71 | ]) | |
72 | ||
73 | return self._download_json( | |
74 | 'https://%s%s%s' % (self._AWS_PROXY_HOST, aws_dict['uri'], '?' + canonical_querystring if canonical_querystring else ''), | |
75 | video_id, headers=headers) |