feat: generate label map on the backend (#21124)

superset/utils/pandas_postprocessing/__init__.py

@@ -33,6 +33,10 @@ from superset.utils.pandas_postprocessing.resample import resample
 from superset.utils.pandas_postprocessing.rolling import rolling
 from superset.utils.pandas_postprocessing.select import select
 from superset.utils.pandas_postprocessing.sort import sort
+from superset.utils.pandas_postprocessing.utils import (
+    escape_separator,
+    unescape_separator,
+)
 
 __all__ = [
     "aggregate",
@@ -52,4 +56,6 @@ __all__ = [
     "select",
     "sort",
     "flatten",
+    "escape_separator",
+    "unescape_separator",
 ]

superset/utils/pandas_postprocessing/flatten.py

@@ -22,6 +22,7 @@ from numpy.distutils.misc_util import is_sequence
 
 from superset.utils.pandas_postprocessing.utils import (
     _is_multi_index_on_columns,
+    escape_separator,
     FLAT_COLUMN_SEPARATOR,
 )
 
@@ -86,8 +87,8 @@ def flatten(
             _cells = []
             for cell in series if is_sequence(series) else [series]:
                 if pd.notnull(cell):
-                    # every cell should be converted to string
-                    _cells.append(str(cell))
+                    # every cell should be converted to string and escape comma
+                    _cells.append(escape_separator(str(cell)))
             _columns.append(FLAT_COLUMN_SEPARATOR.join(_cells))
 
         df.columns = _columns

superset/utils/pandas_postprocessing/utils.py

@@ -198,3 +198,13 @@ def _append_columns(
         return _base_df
     append_df = append_df.rename(columns=columns)
     return pd.concat([base_df, append_df], axis="columns")
+
+
+def escape_separator(plain_str: str, sep: str = FLAT_COLUMN_SEPARATOR) -> str:
+    char = sep.strip()
+    return plain_str.replace(char, "\\" + char)
+
+
+def unescape_separator(escaped_str: str, sep: str = FLAT_COLUMN_SEPARATOR) -> str:
+    char = sep.strip()
+    return escaped_str.replace("\\" + char, char)