remove cgi module usage, which causes deprecation warnings on Python …

…3.11 (#2794)

botocore/utils.py

@@ -12,8 +12,8 @@
 # language governing permissions and limitations under the License.
 import base64
 import binascii
-import cgi
 import datetime
+import email.message
 import functools
 import hashlib
 import io
@@ -3011,10 +3011,12 @@ def get_encoding_from_headers(headers, default='ISO-8859-1'):
     if not content_type:
         return None
 
-    content_type, params = cgi.parse_header(content_type)
+    message = email.message.Message()
+    message['content-type'] = content_type
+    charset = message.get_param("charset")
 
-    if 'charset' in params:
-        return params['charset'].strip("'\"")
+    if charset is not None:
+        return charset
 
     if 'text' in content_type:
         return default

tests/unit/test_utils.py

@@ -68,6 +68,7 @@
     determine_content_length,
     ensure_boolean,
     fix_s3_host,
+    get_encoding_from_headers,
     get_service_module_name,
     has_header,
     instance_cache,
@@ -3372,3 +3373,18 @@ def seek(self, *args, **kwargs):
 )
 def test_is_s3_accelerate_url(url, expected):
     assert is_s3_accelerate_url(url) == expected
+
+
+@pytest.mark.parametrize(
+    'headers, default, expected',
+    (
+        ({}, 'ISO-8859-1', None),
+        ({'Content-Type': 'text/html; charset=utf-8'}, 'default', 'utf-8'),
+        ({'Content-Type': 'text/html; charset="utf-8"'}, 'default', 'utf-8'),
+        ({'Content-Type': 'text/html'}, 'ascii', 'ascii'),
+        ({'Content-Type': 'application/json'}, 'ISO-8859-1', None),
+    ),
+)
+def test_get_encoding_from_headers(headers, default, expected):
+    charset = get_encoding_from_headers(HeadersDict(headers), default=default)
+    assert charset == expected