1 files changed, 78 insertions, 0 deletions
diff --git a/youtube_dl/extractor/aws.py b/youtube_dl/extractor/aws.py
new file mode 100644
index 000000000..670abce0c
--- /dev/null
+++ b/youtube_dl/extractor/aws.py
@@ -0,0 +1,78 @@
+# coding: utf-8
+from __future__ import unicode_literals
+
+import datetime
+import hashlib
+import hmac
+
+from .common import InfoExtractor
+from ..compat import compat_urllib_parse_urlencode
+
+
+class AWSIE(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.utcnow().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,
+        }
+        session_token = aws_dict.get('session_token')
+        if session_token:
+            headers['X-Amz-Security-Token'] = session_token
+        headers['X-Api-Key'] = self._AWS_API_KEY
+
+        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 headers.items():
+            canonical_headers += '%s:%s\n' % (header_name.lower(), header_value)
+        signed_headers = ';'.join([header.lower() for header in 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)