Make new model IDs only contain alphanumeric characters. (oppia#6408)

* Make new model IDs only contain alphanumeric characters. * Add test for alphanumeric chars.
sargamm · Mar 10, 2019 · 4617d80 · 4617d80
1 parent 5706cf1
commit 4617d80
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Showing 2 changed files with 6 additions and 2 deletions.
diff --git a/utils.py b/utils.py
@@ -424,8 +424,11 @@ def convert_to_hash(input_string, max_length):
             'Expected string, received %s of type %s' %
             (input_string, type(input_string)))
 
-    encoded_string = base64.urlsafe_b64encode(
-        hashlib.sha1(input_string.encode('utf-8')).digest())
+    # Encodes strings using the character set [A-Za-z0-9].
+    encoded_string = base64.b64encode(
+        hashlib.sha1(input_string.encode('utf-8')).digest(),
+        altchars='ab'
+    ).replace('=', 'c')
 
     return encoded_string[:max_length]
 

diff --git a/utils_test.py b/utils_test.py
@@ -158,6 +158,7 @@ def test_convert_to_hash(self):
         self.assertEqual(len(full_hash), 28)
         self.assertEqual(len(abbreviated_hash), 5)
         self.assertEqual(full_hash[:5], abbreviated_hash)
+        self.assertTrue(full_hash.isalnum())
 
     def test_vfs_construct_path(self):
         """Test vfs_construct_path method."""