diff --git a/Lib/email/utils.py b/Lib/email/utils.py
index e1d21f6..35275f6 100644
--- a/Lib/email/utils.py
+++ b/Lib/email/utils.py
@@ -219,7 +219,7 @@
     charset is given but not language, the string is encoded using the empty
     string for language.
     """
-    s = urllib.parse.quote(s, safe='')
+    s = urllib.parse.quote(s, safe='', encoding=charset or 'ascii')
     if charset is None and language is None:
         return s
     if language is None:
@@ -271,7 +271,10 @@
             # language specifiers at the beginning of the string.
             for num, s, encoded in continuations:
                 if encoded:
-                    s = urllib.parse.unquote(s)
+                    # Decode as "latin-1", so the characters in s directly
+                    # represent the percent-encoded octet values.
+                    # collapse_rfc2231_value treats this as an octet sequence.
+                    s = urllib.parse.unquote(s, encoding="latin-1")
                     extended = True
                 value.append(s)
             value = quote(EMPTYSTRING.join(value))
diff --git a/Lib/test/test_cgi.py b/Lib/test/test_cgi.py
index 9381a3c..cc11acc 100644
--- a/Lib/test/test_cgi.py
+++ b/Lib/test/test_cgi.py
@@ -68,6 +68,8 @@
     ("&a=b", [('a', 'b')]),
     ("a=a+b&b=b+c", [('a', 'a b'), ('b', 'b c')]),
     ("a=1&a=2", [('a', '1'), ('a', '2')]),
+    ("a=%26&b=%3D", [('a', '&'), ('b', '=')]),
+    ("a=%C3%BC&b=%CA%83", [('a', '\xfc'), ('b', '\u0283')]),
 ]
 
 parse_strict_test_cases = [
diff --git a/Lib/test/test_http_cookiejar.py b/Lib/test/test_http_cookiejar.py
index 1627923..a97c6fa 100644
--- a/Lib/test/test_http_cookiejar.py
+++ b/Lib/test/test_http_cookiejar.py
@@ -539,6 +539,8 @@
             # unquoted unsafe
             ("/foo\031/bar", "/foo%19/bar"),
             ("/\175foo/bar", "/%7Dfoo/bar"),
+            # unicode, latin-1 range
+            ("/foo/bar\u00fc", "/foo/bar%C3%BC"),     # UTF-8 encoded
             # unicode
             ("/foo/bar\uabcd", "/foo/bar%EA%AF%8D"),  # UTF-8 encoded
             ]
@@ -1444,7 +1446,8 @@
         # Try some URL encodings of the PATHs.
         # (the behaviour here has changed from libwww-perl)
         c = CookieJar(DefaultCookiePolicy(rfc2965=True))
-        interact_2965(c, "http://www.acme.com/foo%2f%25/%3c%3c%0Anew%E5/%E5",
+        interact_2965(c, "http://www.acme.com/foo%2f%25/"
+                         "%3c%3c%0Anew%C3%A5/%C3%A5",
                       "foo  =   bar; version    =   1")
 
         cookie = interact_2965(
diff --git a/Lib/test/test_urllib.py b/Lib/test/test_urllib.py
index f5a9d5d..a8a8111 100644
--- a/Lib/test/test_urllib.py
+++ b/Lib/test/test_urllib.py
@@ -336,10 +336,10 @@
                                  "_.-"])
         result = urllib.parse.quote(do_not_quote)
         self.assertEqual(do_not_quote, result,
-                         "using quote(): %s != %s" % (do_not_quote, result))
+                         "using quote(): %r != %r" % (do_not_quote, result))
         result = urllib.parse.quote_plus(do_not_quote)
         self.assertEqual(do_not_quote, result,
-                        "using quote_plus(): %s != %s" % (do_not_quote, result))
+                        "using quote_plus(): %r != %r" % (do_not_quote, result))
 
     def test_default_safe(self):
         # Test '/' is default value for 'safe' parameter
@@ -350,11 +350,28 @@
         quote_by_default = "<>"
         result = urllib.parse.quote(quote_by_default, safe=quote_by_default)
         self.assertEqual(quote_by_default, result,
-                         "using quote(): %s != %s" % (quote_by_default, result))
+                         "using quote(): %r != %r" % (quote_by_default, result))
         result = urllib.parse.quote_plus(quote_by_default, safe=quote_by_default)
         self.assertEqual(quote_by_default, result,
-                         "using quote_plus(): %s != %s" %
+                         "using quote_plus(): %r != %r" %
                          (quote_by_default, result))
+        # Safe expressed as bytes rather than str
+        result = urllib.parse.quote(quote_by_default, safe=b"<>")
+        self.assertEqual(quote_by_default, result,
+                         "using quote(): %r != %r" % (quote_by_default, result))
+        # "Safe" non-ASCII characters should have no effect
+        # (Since URIs are not allowed to have non-ASCII characters)
+        result = urllib.parse.quote("a\xfcb", encoding="latin-1", safe="\xfc")
+        expect = urllib.parse.quote("a\xfcb", encoding="latin-1", safe="")
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" %
+                         (expect, result))
+        # Same as above, but using a bytes rather than str
+        result = urllib.parse.quote("a\xfcb", encoding="latin-1", safe=b"\xfc")
+        expect = urllib.parse.quote("a\xfcb", encoding="latin-1", safe="")
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" %
+                         (expect, result))
 
     def test_default_quoting(self):
         # Make sure all characters that should be quoted are by default sans
@@ -378,34 +395,98 @@
         expected = "ab%5B%5Dcd"
         result = urllib.parse.quote(partial_quote)
         self.assertEqual(expected, result,
-                         "using quote(): %s != %s" % (expected, result))
+                         "using quote(): %r != %r" % (expected, result))
         self.assertEqual(expected, result,
-                         "using quote_plus(): %s != %s" % (expected, result))
+                         "using quote_plus(): %r != %r" % (expected, result))
 
     def test_quoting_space(self):
         # Make sure quote() and quote_plus() handle spaces as specified in
         # their unique way
         result = urllib.parse.quote(' ')
         self.assertEqual(result, hexescape(' '),
-                         "using quote(): %s != %s" % (result, hexescape(' ')))
+                         "using quote(): %r != %r" % (result, hexescape(' ')))
         result = urllib.parse.quote_plus(' ')
         self.assertEqual(result, '+',
-                         "using quote_plus(): %s != +" % result)
+                         "using quote_plus(): %r != +" % result)
         given = "a b cd e f"
         expect = given.replace(' ', hexescape(' '))
         result = urllib.parse.quote(given)
         self.assertEqual(expect, result,
-                         "using quote(): %s != %s" % (expect, result))
+                         "using quote(): %r != %r" % (expect, result))
         expect = given.replace(' ', '+')
         result = urllib.parse.quote_plus(given)
         self.assertEqual(expect, result,
-                         "using quote_plus(): %s != %s" % (expect, result))
+                         "using quote_plus(): %r != %r" % (expect, result))
 
     def test_quoting_plus(self):
         self.assertEqual(urllib.parse.quote_plus('alpha+beta gamma'),
                          'alpha%2Bbeta+gamma')
         self.assertEqual(urllib.parse.quote_plus('alpha+beta gamma', '+'),
                          'alpha+beta+gamma')
+        # Test with bytes
+        self.assertEqual(urllib.parse.quote_plus(b'alpha+beta gamma'),
+                         'alpha%2Bbeta+gamma')
+        # Test with safe bytes
+        self.assertEqual(urllib.parse.quote_plus('alpha+beta gamma', b'+'),
+                         'alpha+beta+gamma')
+
+    def test_quote_bytes(self):
+        # Bytes should quote directly to percent-encoded values
+        given = b"\xa2\xd8ab\xff"
+        expect = "%A2%D8ab%FF"
+        result = urllib.parse.quote(given)
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" % (expect, result))
+        # Encoding argument should raise type error on bytes input
+        self.assertRaises(TypeError, urllib.parse.quote, given,
+                            encoding="latin-1")
+        # quote_from_bytes should work the same
+        result = urllib.parse.quote_from_bytes(given)
+        self.assertEqual(expect, result,
+                         "using quote_from_bytes(): %r != %r"
+                         % (expect, result))
+
+    def test_quote_with_unicode(self):
+        # Characters in Latin-1 range, encoded by default in UTF-8
+        given = "\xa2\xd8ab\xff"
+        expect = "%C2%A2%C3%98ab%C3%BF"
+        result = urllib.parse.quote(given)
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" % (expect, result))
+        # Characters in Latin-1 range, encoded by with None (default)
+        result = urllib.parse.quote(given, encoding=None, errors=None)
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" % (expect, result))
+        # Characters in Latin-1 range, encoded with Latin-1
+        given = "\xa2\xd8ab\xff"
+        expect = "%A2%D8ab%FF"
+        result = urllib.parse.quote(given, encoding="latin-1")
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" % (expect, result))
+        # Characters in BMP, encoded by default in UTF-8
+        given = "\u6f22\u5b57"              # "Kanji"
+        expect = "%E6%BC%A2%E5%AD%97"
+        result = urllib.parse.quote(given)
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" % (expect, result))
+        # Characters in BMP, encoded with Latin-1
+        given = "\u6f22\u5b57"
+        self.assertRaises(UnicodeEncodeError, urllib.parse.quote, given,
+                                    encoding="latin-1")
+        # Characters in BMP, encoded with Latin-1, with replace error handling
+        given = "\u6f22\u5b57"
+        expect = "%3F%3F"                   # "??"
+        result = urllib.parse.quote(given, encoding="latin-1",
+                                    errors="replace")
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" % (expect, result))
+        # Characters in BMP, Latin-1, with xmlcharref error handling
+        given = "\u6f22\u5b57"
+        expect = "%26%2328450%3B%26%2323383%3B"     # "&#28450;&#23383;"
+        result = urllib.parse.quote(given, encoding="latin-1",
+                                    errors="xmlcharrefreplace")
+        self.assertEqual(expect, result,
+                         "using quote(): %r != %r" % (expect, result))
 
 class UnquotingTests(unittest.TestCase):
     """Tests for unquote() and unquote_plus()
@@ -422,23 +503,62 @@
             expect = chr(num)
             result = urllib.parse.unquote(given)
             self.assertEqual(expect, result,
-                             "using unquote(): %s != %s" % (expect, result))
+                             "using unquote(): %r != %r" % (expect, result))
             result = urllib.parse.unquote_plus(given)
             self.assertEqual(expect, result,
-                             "using unquote_plus(): %s != %s" %
+                             "using unquote_plus(): %r != %r" %
                              (expect, result))
             escape_list.append(given)
         escape_string = ''.join(escape_list)
         del escape_list
         result = urllib.parse.unquote(escape_string)
         self.assertEqual(result.count('%'), 1,
-                         "using quote(): not all characters escaped; %s" %
-                         result)
-        result = urllib.parse.unquote(escape_string)
-        self.assertEqual(result.count('%'), 1,
                          "using unquote(): not all characters escaped: "
                          "%s" % result)
 
+    def test_unquoting_badpercent(self):
+        # Test unquoting on bad percent-escapes
+        given = '%xab'
+        expect = given
+        result = urllib.parse.unquote(given)
+        self.assertEqual(expect, result, "using unquote(): %r != %r"
+                         % (expect, result))
+        given = '%x'
+        expect = given
+        result = urllib.parse.unquote(given)
+        self.assertEqual(expect, result, "using unquote(): %r != %r"
+                         % (expect, result))
+        given = '%'
+        expect = given
+        result = urllib.parse.unquote(given)
+        self.assertEqual(expect, result, "using unquote(): %r != %r"
+                         % (expect, result))
+        # unquote_to_bytes
+        given = '%xab'
+        expect = bytes(given, 'ascii')
+        result = urllib.parse.unquote_to_bytes(given)
+        self.assertEqual(expect, result, "using unquote_to_bytes(): %r != %r"
+                         % (expect, result))
+        given = '%x'
+        expect = bytes(given, 'ascii')
+        result = urllib.parse.unquote_to_bytes(given)
+        self.assertEqual(expect, result, "using unquote_to_bytes(): %r != %r"
+                         % (expect, result))
+        given = '%'
+        expect = bytes(given, 'ascii')
+        result = urllib.parse.unquote_to_bytes(given)
+        self.assertEqual(expect, result, "using unquote_to_bytes(): %r != %r"
+                         % (expect, result))
+
+    def test_unquoting_mixed_case(self):
+        # Test unquoting on mixed-case hex digits in the percent-escapes
+        given = '%Ab%eA'
+        expect = b'\xab\xea'
+        result = urllib.parse.unquote_to_bytes(given)
+        self.assertEqual(expect, result,
+                         "using unquote_to_bytes(): %r != %r"
+                         % (expect, result))
+
     def test_unquoting_parts(self):
         # Make sure unquoting works when have non-quoted characters
         # interspersed
@@ -446,10 +566,10 @@
         expect = "abcd"
         result = urllib.parse.unquote(given)
         self.assertEqual(expect, result,
-                         "using quote(): %s != %s" % (expect, result))
+                         "using quote(): %r != %r" % (expect, result))
         result = urllib.parse.unquote_plus(given)
         self.assertEqual(expect, result,
-                         "using unquote_plus(): %s != %s" % (expect, result))
+                         "using unquote_plus(): %r != %r" % (expect, result))
 
     def test_unquoting_plus(self):
         # Test difference between unquote() and unquote_plus()
@@ -457,15 +577,100 @@
         expect = given
         result = urllib.parse.unquote(given)
         self.assertEqual(expect, result,
-                         "using unquote(): %s != %s" % (expect, result))
+                         "using unquote(): %r != %r" % (expect, result))
         expect = given.replace('+', ' ')
         result = urllib.parse.unquote_plus(given)
         self.assertEqual(expect, result,
-                         "using unquote_plus(): %s != %s" % (expect, result))
+                         "using unquote_plus(): %r != %r" % (expect, result))
+
+    def test_unquote_to_bytes(self):
+        given = 'br%C3%BCckner_sapporo_20050930.doc'
+        expect = b'br\xc3\xbcckner_sapporo_20050930.doc'
+        result = urllib.parse.unquote_to_bytes(given)
+        self.assertEqual(expect, result,
+                         "using unquote_to_bytes(): %r != %r"
+                         % (expect, result))
+        # Test on a string with unescaped non-ASCII characters
+        # (Technically an invalid URI; expect those characters to be UTF-8
+        # encoded).
+        result = urllib.parse.unquote_to_bytes("\u6f22%C3%BC")
+        expect = b'\xe6\xbc\xa2\xc3\xbc'    # UTF-8 for "\u6f22\u00fc"
+        self.assertEqual(expect, result,
+                         "using unquote_to_bytes(): %r != %r"
+                         % (expect, result))
+        # Test with a bytes as input
+        given = b'%A2%D8ab%FF'
+        expect = b'\xa2\xd8ab\xff'
+        result = urllib.parse.unquote_to_bytes(given)
+        self.assertEqual(expect, result,
+                         "using unquote_to_bytes(): %r != %r"
+                         % (expect, result))
+        # Test with a bytes as input, with unescaped non-ASCII bytes
+        # (Technically an invalid URI; expect those bytes to be preserved)
+        given = b'%A2\xd8ab%FF'
+        expect = b'\xa2\xd8ab\xff'
+        result = urllib.parse.unquote_to_bytes(given)
+        self.assertEqual(expect, result,
+                         "using unquote_to_bytes(): %r != %r"
+                         % (expect, result))
 
     def test_unquote_with_unicode(self):
-        r = urllib.parse.unquote('br%C3%BCckner_sapporo_20050930.doc')
-        self.assertEqual(r, 'br\xc3\xbcckner_sapporo_20050930.doc')
+        # Characters in the Latin-1 range, encoded with UTF-8
+        given = 'br%C3%BCckner_sapporo_20050930.doc'
+        expect = 'br\u00fcckner_sapporo_20050930.doc'
+        result = urllib.parse.unquote(given)
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
+        # Characters in the Latin-1 range, encoded with None (default)
+        result = urllib.parse.unquote(given, encoding=None, errors=None)
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
+
+        # Characters in the Latin-1 range, encoded with Latin-1
+        result = urllib.parse.unquote('br%FCckner_sapporo_20050930.doc',
+                                      encoding="latin-1")
+        expect = 'br\u00fcckner_sapporo_20050930.doc'
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
+
+        # Characters in BMP, encoded with UTF-8
+        given = "%E6%BC%A2%E5%AD%97"
+        expect = "\u6f22\u5b57"             # "Kanji"
+        result = urllib.parse.unquote(given)
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
+
+        # Decode with UTF-8, invalid sequence
+        given = "%F3%B1"
+        expect = "\ufffd"                   # Replacement character
+        result = urllib.parse.unquote(given)
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
+
+        # Decode with UTF-8, invalid sequence, replace errors
+        result = urllib.parse.unquote(given, errors="replace")
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
+
+        # Decode with UTF-8, invalid sequence, ignoring errors
+        given = "%F3%B1"
+        expect = ""
+        result = urllib.parse.unquote(given, errors="ignore")
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
+
+        # A mix of non-ASCII and percent-encoded characters, UTF-8
+        result = urllib.parse.unquote("\u6f22%C3%BC")
+        expect = '\u6f22\u00fc'
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
+
+        # A mix of non-ASCII and percent-encoded characters, Latin-1
+        # (Note, the string contains non-Latin-1-representable characters)
+        result = urllib.parse.unquote("\u6f22%FC", encoding="latin-1")
+        expect = '\u6f22\u00fc'
+        self.assertEqual(expect, result,
+                         "using unquote(): %r != %r" % (expect, result))
 
 class urlencode_Tests(unittest.TestCase):
     """Tests for urlencode()"""
diff --git a/Lib/test/test_wsgiref.py b/Lib/test/test_wsgiref.py
index ac5ada3..b98452d 100755
--- a/Lib/test/test_wsgiref.py
+++ b/Lib/test/test_wsgiref.py
@@ -291,6 +291,7 @@
     def testAppURIs(self):
         self.checkAppURI("http://127.0.0.1/")
         self.checkAppURI("http://127.0.0.1/spam", SCRIPT_NAME="/spam")
+        self.checkAppURI("http://127.0.0.1/sp%C3%A4m", SCRIPT_NAME="/späm")
         self.checkAppURI("http://spam.example.com:2071/",
             HTTP_HOST="spam.example.com:2071", SERVER_PORT="2071")
         self.checkAppURI("http://spam.example.com/",
@@ -304,6 +305,7 @@
     def testReqURIs(self):
         self.checkReqURI("http://127.0.0.1/")
         self.checkReqURI("http://127.0.0.1/spam", SCRIPT_NAME="/spam")
+        self.checkReqURI("http://127.0.0.1/sp%C3%A4m", SCRIPT_NAME="/späm")
         self.checkReqURI("http://127.0.0.1/spammity/spam",
             SCRIPT_NAME="/spammity", PATH_INFO="/spam")
         self.checkReqURI("http://127.0.0.1/spammity/spam?say=ni",
diff --git a/Lib/urllib/parse.py b/Lib/urllib/parse.py
index 3e00695..94d77eb 100644
--- a/Lib/urllib/parse.py
+++ b/Lib/urllib/parse.py
@@ -5,9 +5,12 @@
 """
 
 import sys
+import collections
 
 __all__ = ["urlparse", "urlunparse", "urljoin", "urldefrag",
-           "urlsplit", "urlunsplit"]
+           "urlsplit", "urlunsplit",
+           "quote", "quote_plus", "quote_from_bytes",
+           "unquote", "unquote_plus", "unquote_to_bytes"]
 
 # A classification of schemes ('' means apply by default)
 uses_relative = ['ftp', 'http', 'gopher', 'nntp', 'imap',
@@ -269,50 +272,101 @@
     else:
         return url, ''
 
-
-_hextochr = dict(('%02x' % i, chr(i)) for i in range(256))
-_hextochr.update(('%02X' % i, chr(i)) for i in range(256))
-
-def unquote(s):
-    """unquote('abc%20def') -> 'abc def'."""
-    res = s.split('%')
+def unquote_to_bytes(string):
+    """unquote_to_bytes('abc%20def') -> b'abc def'."""
+    # Note: strings are encoded as UTF-8. This is only an issue if it contains
+    # unescaped non-ASCII characters, which URIs should not.
+    if isinstance(string, str):
+        string = string.encode('utf-8')
+    res = string.split(b'%')
+    res[0] = res[0]
     for i in range(1, len(res)):
         item = res[i]
         try:
-            res[i] = _hextochr[item[:2]] + item[2:]
-        except KeyError:
-            res[i] = '%' + item
-        except UnicodeDecodeError:
-            res[i] = chr(int(item[:2], 16)) + item[2:]
-    return "".join(res)
+            res[i] = bytes([int(item[:2], 16)]) + item[2:]
+        except ValueError:
+            res[i] = b'%' + item
+    return b''.join(res)
 
-def unquote_plus(s):
-    """unquote('%7e/abc+def') -> '~/abc def'"""
-    s = s.replace('+', ' ')
-    return unquote(s)
+def unquote(string, encoding='utf-8', errors='replace'):
+    """Replace %xx escapes by their single-character equivalent. The optional
+    encoding and errors parameters specify how to decode percent-encoded
+    sequences into Unicode characters, as accepted by the bytes.decode()
+    method.
+    By default, percent-encoded sequences are decoded with UTF-8, and invalid
+    sequences are replaced by a placeholder character.
 
-always_safe = ('ABCDEFGHIJKLMNOPQRSTUVWXYZ'
-               'abcdefghijklmnopqrstuvwxyz'
-               '0123456789' '_.-')
+    unquote('abc%20def') -> 'abc def'.
+    """
+    if encoding is None: encoding = 'utf-8'
+    if errors is None: errors = 'replace'
+    # pct_sequence: contiguous sequence of percent-encoded bytes, decoded
+    # (list of single-byte bytes objects)
+    pct_sequence = []
+    res = string.split('%')
+    for i in range(1, len(res)):
+        item = res[i]
+        try:
+            if not item: raise ValueError
+            pct_sequence.append(bytes.fromhex(item[:2]))
+            rest = item[2:]
+        except ValueError:
+            rest = '%' + item
+        if not rest:
+            # This segment was just a single percent-encoded character.
+            # May be part of a sequence of code units, so delay decoding.
+            # (Stored in pct_sequence).
+            res[i] = ''
+        else:
+            # Encountered non-percent-encoded characters. Flush the current
+            # pct_sequence.
+            res[i] = b''.join(pct_sequence).decode(encoding, errors) + rest
+            pct_sequence = []
+    if pct_sequence:
+        # Flush the final pct_sequence
+        # res[-1] will always be empty if pct_sequence != []
+        assert not res[-1], "string=%r, res=%r" % (string, res)
+        res[-1] = b''.join(pct_sequence).decode(encoding, errors)
+    return ''.join(res)
+
+def unquote_plus(string, encoding='utf-8', errors='replace'):
+    """Like unquote(), but also replace plus signs by spaces, as required for
+    unquoting HTML form values.
+
+    unquote_plus('%7e/abc+def') -> '~/abc def'
+    """
+    string = string.replace('+', ' ')
+    return unquote(string, encoding, errors)
+
+_ALWAYS_SAFE = frozenset(b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+                         b'abcdefghijklmnopqrstuvwxyz'
+                         b'0123456789'
+                         b'_.-')
 _safe_quoters= {}
 
-class Quoter:
+class Quoter(collections.defaultdict):
+    """A mapping from bytes (in range(0,256)) to strings.
+
+    String values are percent-encoded byte values, unless the key < 128, and
+    in the "safe" set (either the specified safe set, or default set).
+    """
+    # Keeps a cache internally, using defaultdict, for efficiency (lookups
+    # of cached keys don't call Python code at all).
     def __init__(self, safe):
-        self.cache = {}
-        self.safe = safe + always_safe
+        """safe: bytes object."""
+        self.safe = _ALWAYS_SAFE.union(c for c in safe if c < 128)
 
-    def __call__(self, c):
-        try:
-            return self.cache[c]
-        except KeyError:
-            if ord(c) < 256:
-                res = (c in self.safe) and c or ('%%%02X' % ord(c))
-                self.cache[c] = res
-                return res
-            else:
-                return "".join(['%%%02X' % i for i in c.encode("utf-8")])
+    def __repr__(self):
+        # Without this, will just display as a defaultdict
+        return "<Quoter %r>" % dict(self)
 
-def quote(s, safe = '/'):
+    def __missing__(self, b):
+        # Handle a cache miss. Store quoted string in cache and return.
+        res = b in self.safe and chr(b) or ('%%%02X' % b)
+        self[b] = res
+        return res
+
+def quote(string, safe='/', encoding=None, errors=None):
     """quote('abc def') -> 'abc%20def'
 
     Each part of a URL, e.g. the path info, the query, etc., has a
@@ -332,22 +386,57 @@
     is reserved, but in typical usage the quote function is being
     called on a path where the existing slash characters are used as
     reserved characters.
+
+    string and safe may be either str or bytes objects. encoding must
+    not be specified if string is a str.
+
+    The optional encoding and errors parameters specify how to deal with
+    non-ASCII characters, as accepted by the str.encode method.
+    By default, encoding='utf-8' (characters are encoded with UTF-8), and
+    errors='strict' (unsupported characters raise a UnicodeEncodeError).
     """
-    cachekey = (safe, always_safe)
+    if isinstance(string, str):
+        if encoding is None:
+            encoding = 'utf-8'
+        if errors is None:
+            errors = 'strict'
+        string = string.encode(encoding, errors)
+    else:
+        if encoding is not None:
+            raise TypeError("quote() doesn't support 'encoding' for bytes")
+        if errors is not None:
+            raise TypeError("quote() doesn't support 'errors' for bytes")
+    return quote_from_bytes(string, safe)
+
+def quote_plus(string, safe='', encoding=None, errors=None):
+    """Like quote(), but also replace ' ' with '+', as required for quoting
+    HTML form values. Plus signs in the original string are escaped unless
+    they are included in safe. It also does not have safe default to '/'.
+    """
+    # Check if ' ' in string, where string may either be a str or bytes
+    if ' ' in string if isinstance(string, str) else b' ' in string:
+        string = quote(string,
+                       safe + ' ' if isinstance(safe, str) else safe + b' ')
+        return string.replace(' ', '+')
+    return quote(string, safe, encoding, errors)
+
+def quote_from_bytes(bs, safe='/'):
+    """Like quote(), but accepts a bytes object rather than a str, and does
+    not perform string-to-bytes encoding.  It always returns an ASCII string.
+    quote_from_bytes(b'abc def\xab') -> 'abc%20def%AB'
+    """
+    if isinstance(safe, str):
+        # Normalize 'safe' by converting to bytes and removing non-ASCII chars
+        safe = safe.encode('ascii', 'ignore')
+    cachekey = bytes(safe)  # In case it was a bytearray
+    if not (isinstance(bs, bytes) or isinstance(bs, bytearray)):
+        raise TypeError("quote_from_bytes() expected a bytes")
     try:
         quoter = _safe_quoters[cachekey]
     except KeyError:
         quoter = Quoter(safe)
         _safe_quoters[cachekey] = quoter
-    res = map(quoter, s)
-    return ''.join(res)
-
-def quote_plus(s, safe = ''):
-    """Quote the query fragment of a URL; replacing ' ' with '+'"""
-    if ' ' in s:
-        s = quote(s, safe + ' ')
-        return s.replace(' ', '+')
-    return quote(s, safe)
+    return ''.join(map(quoter.__getitem__, bs))
 
 def urlencode(query,doseq=0):
     """Encode a sequence of two-element tuples or dictionary into a URL query string.