PERF: styler uuid control and security (pandas-dev#36345)

Author: attack68

doc/source/whatsnew/v1.2.0.rst

@@ -226,6 +226,7 @@ Performance improvements
 - Performance improvement in :meth:`GroupBy.agg` with the ``numba`` engine (:issue:`35759`)
 - Performance improvements when creating :meth:`pd.Series.map` from a huge dictionary (:issue:`34717`)
 - Performance improvement in :meth:`GroupBy.transform` with the ``numba`` engine (:issue:`36240`)
+- ``Styler`` uuid method altered to compress data transmission over web whilst maintaining reasonably low table collision probability (:issue:`36345`)
 
 .. ---------------------------------------------------------------------------
 

pandas/io/formats/style.py

@@ -18,7 +18,7 @@
     Tuple,
     Union,
 )
-from uuid import uuid1
+from uuid import uuid4
 
 import numpy as np
 
@@ -89,6 +89,12 @@ class Styler:
 
         .. versionadded:: 1.0.0
 
+    uuid_len : int, default 5
+        If ``uuid`` is not specified, the length of the ``uuid`` to randomly generate
+        expressed in hex characters, in range [0, 32].
+
+        .. versionadded:: 1.2.0
+
     Attributes
     ----------
     env : Jinja2 jinja2.Environment
@@ -144,6 +150,7 @@ def __init__(
         table_attributes: Optional[str] = None,
         cell_ids: bool = True,
         na_rep: Optional[str] = None,
+        uuid_len: int = 5,
     ):
         self.ctx: DefaultDict[Tuple[int, int], List[str]] = defaultdict(list)
         self._todo: List[Tuple[Callable, Tuple, Dict]] = []
@@ -159,7 +166,10 @@ def __init__(
         self.index = data.index
         self.columns = data.columns
 
-        self.uuid = uuid
+        if not isinstance(uuid_len, int) or not uuid_len >= 0:
+            raise TypeError("``uuid_len`` must be an integer in range [0, 32].")
+        self.uuid_len = min(32, uuid_len)
+        self.uuid = (uuid or uuid4().hex[: self.uuid_len]) + "_"
         self.table_styles = table_styles
         self.caption = caption
         if precision is None:
@@ -248,7 +258,7 @@ def _translate(self):
         precision = self.precision
         hidden_index = self.hidden_index
         hidden_columns = self.hidden_columns
-        uuid = self.uuid or str(uuid1()).replace("-", "_")
+        uuid = self.uuid
         ROW_HEADING_CLASS = "row_heading"
         COL_HEADING_CLASS = "col_heading"
         INDEX_NAME_CLASS = "index_name"

pandas/tests/io/formats/test_style.py

@@ -1718,6 +1718,26 @@ def test_colspan_w3(self):
         s = Styler(df, uuid="_", cell_ids=False)
         assert '<th class="col_heading level0 col0" colspan="2">l0</th>' in s.render()
 
+    @pytest.mark.parametrize("len_", [1, 5, 32, 33, 100])
+    def test_uuid_len(self, len_):
+        # GH 36345
+        df = pd.DataFrame(data=[["A"]])
+        s = Styler(df, uuid_len=len_, cell_ids=False).render()
+        strt = s.find('id="T_')
+        end = s[strt + 6 :].find('"')
+        if len_ > 32:
+            assert end == 32 + 1
+        else:
+            assert end == len_ + 1
+
+    @pytest.mark.parametrize("len_", [-2, "bad", None])
+    def test_uuid_len_raises(self, len_):
+        # GH 36345
+        df = pd.DataFrame(data=[["A"]])
+        msg = "``uuid_len`` must be an integer in range \\[0, 32\\]."
+        with pytest.raises(TypeError, match=msg):
+            Styler(df, uuid_len=len_, cell_ids=False).render()
+
 
 @td.skip_if_no_mpl
 class TestStylerMatplotlibDep: