imprv: Add SASLprep profile

2 files changed, 102 insertions, 0 deletions

diff --git a/nbxmpp/stringprep.py b/nbxmpp/stringprep.py
index 84943e4..9f3a43e 100644
--- a/nbxmpp/stringprep.py
+++ b/nbxmpp/stringprep.py
@@ -241,3 +241,51 @@ def nameprep(string: str, allow_unassigned: bool = False) -> str:
         )
 
     return ''.join(chars)
+
+
+def _saslprep_do_mapping(chars: list[str]) -> None:
+    i = 0
+    while i < len(chars):
+        c = chars[i]
+        if stringprep.in_table_b1(c):
+            del chars[i]
+
+        elif stringprep.in_table_c12(c):
+            chars[i] = ' '
+
+        i += 1
+
+
+def saslprep(string: str, allow_unassigned: bool = False) -> str:
+    '''
+    Process the given `string` using the SASLprep (`RFC 4013`_) profile.
+    '''
+
+    chars = list(string)
+    _saslprep_do_mapping(chars)
+    do_normalization(chars)
+    check_against_tables(
+        chars,
+        (
+            stringprep.in_table_c12,
+            stringprep.in_table_c21,
+            stringprep.in_table_c22,
+            stringprep.in_table_c3,
+            stringprep.in_table_c4,
+            stringprep.in_table_c5,
+            stringprep.in_table_c6,
+            stringprep.in_table_c7,
+            stringprep.in_table_c8,
+            stringprep.in_table_c9,
+        ))
+    check_bidi(chars)
+
+    if not allow_unassigned:
+        check_against_tables(
+            chars,
+            (
+                stringprep.in_table_a1,
+            )
+        )
+
+    return ''.join(chars)
diff --git a/test/unit/test_stringprep.py b/test/unit/test_stringprep.py
index 06cb769..5817a29 100644
--- a/test/unit/test_stringprep.py
+++ b/test/unit/test_stringprep.py
@@ -1,6 +1,7 @@
 import unittest
 
 from nbxmpp.stringprep import nodeprep
+from nbxmpp.stringprep import saslprep
 from nbxmpp.stringprep import resourceprep
 from nbxmpp.stringprep import nameprep
 from nbxmpp.stringprep import check_bidi
@@ -201,3 +202,56 @@ class TestResourceprep(unittest.TestCase):
         self.assertEqual(
             '\u0221',
             resourceprep('\u0221', allow_unassigned=True))
+
+
+class TestSASLprep(unittest.TestCase):
+    def test_map_to_nothing(self):
+        self.assertEqual(
+            'IX',
+            saslprep('I\u00ADX'),
+            'SASLprep requirement: map SOFT HYPHEN to nothing')
+
+    def test_nfkc(self):
+        self.assertEqual(
+            'a',
+            saslprep('\u00AA'),
+            'SASLprep requirement: NFKC')
+        self.assertEqual(
+            'IX',
+            saslprep('\u2168'),
+            'SASLprep requirement: NFKC')
+
+    def test_case_fold(self):
+        self.assertNotEqual(
+            'user',
+            saslprep('USER'),
+            'SASLprep requirement: No CaseFold')
+
+    def test_prohibited_character(self):
+        with self.assertRaisesRegex(
+                ValueError,
+                r'U\+0007',
+                msg='SASLprep requirement: '
+                    'prohibited character (C.2.1)'):
+            saslprep('\u0007')
+
+    def test_bidi_check(self):
+        with self.assertRaises(
+                ValueError,
+                msg='SASLprep requirement: bidi check'):
+            saslprep('\u0627\u0031')
+
+    def test_unassigned(self):
+        with self.assertRaises(
+                ValueError,
+                msg='SASLprep requirement: unassigned'):
+            saslprep('\u0221', allow_unassigned=False)
+
+        with self.assertRaises(
+                ValueError,
+                msg='enforce no unassigned by default'):
+            saslprep('\u0221')
+
+        self.assertEqual(
+            '\u0221',
+            saslprep('\u0221', allow_unassigned=True))