1 files changed, 65 insertions, 0 deletions
diff --git a/python/itsdangerous/url_safe.py b/python/itsdangerous/url_safe.py
new file mode 100644
index 0000000..fcaa011
--- /dev/null
+++ b/python/itsdangerous/url_safe.py
@@ -0,0 +1,65 @@
+import zlib
+
+from ._json import _CompactJSON
+from .encoding import base64_decode
+from .encoding import base64_encode
+from .exc import BadPayload
+from .serializer import Serializer
+from .timed import TimedSerializer
+
+
+class URLSafeSerializerMixin(object):
+    """Mixed in with a regular serializer it will attempt to zlib
+    compress the string to make it shorter if necessary. It will also
+    base64 encode the string so that it can safely be placed in a URL.
+    """
+
+    default_serializer = _CompactJSON
+
+    def load_payload(self, payload, *args, **kwargs):
+        decompress = False
+        if payload.startswith(b"."):
+            payload = payload[1:]
+            decompress = True
+        try:
+            json = base64_decode(payload)
+        except Exception as e:
+            raise BadPayload(
+                "Could not base64 decode the payload because of an exception",
+                original_error=e,
+            )
+        if decompress:
+            try:
+                json = zlib.decompress(json)
+            except Exception as e:
+                raise BadPayload(
+                    "Could not zlib decompress the payload before decoding the payload",
+                    original_error=e,
+                )
+        return super(URLSafeSerializerMixin, self).load_payload(json, *args, **kwargs)
+
+    def dump_payload(self, obj):
+        json = super(URLSafeSerializerMixin, self).dump_payload(obj)
+        is_compressed = False
+        compressed = zlib.compress(json)
+        if len(compressed) < (len(json) - 1):
+            json = compressed
+            is_compressed = True
+        base64d = base64_encode(json)
+        if is_compressed:
+            base64d = b"." + base64d
+        return base64d
+
+
+class URLSafeSerializer(URLSafeSerializerMixin, Serializer):
+    """Works like :class:`.Serializer` but dumps and loads into a URL
+    safe string consisting of the upper and lowercase character of the
+    alphabet as well as ``'_'``, ``'-'`` and ``'.'``.
+    """
+
+
+class URLSafeTimedSerializer(URLSafeSerializerMixin, TimedSerializer):
+    """Works like :class:`.TimedSerializer` but dumps and loads into a
+    URL safe string consisting of the upper and lowercase character of
+    the alphabet as well as ``'_'``, ``'-'`` and ``'.'``.
+    """