Add id to map api (streamlit#7307)

lib/streamlit/elements/map.py

@@ -15,6 +15,7 @@
 """A wrapper for simple PyDeck scatter charts."""
 
 import copy
+import hashlib
 import json
 from typing import (
     TYPE_CHECKING,
@@ -238,12 +239,11 @@ def map(
         #       for information on how to get one and set it up in Streamlit.
         #
         map_style = None
-
         map_proto = DeckGlJsonChartProto()
-        map_proto.json = to_deckgl_json(
+        deck_gl_json = to_deckgl_json(
             data, latitude, longitude, size, color, map_style, zoom
         )
-        map_proto.use_container_width = use_container_width
+        marshall(map_proto, deck_gl_json, use_container_width)
         return self.dg._enqueue("deck_gl_json_chart", map_proto)
 
     @property
@@ -483,3 +483,17 @@ def _get_zoom_level(distance: float) -> int:
 
     # For small number of points the default zoom level will be used.
     return _DEFAULT_ZOOM_LEVEL
+
+
+def marshall(
+    pydeck_proto: DeckGlJsonChartProto,
+    pydeck_json: str,
+    use_container_width: bool,
+) -> None:
+    json_bytes = pydeck_json.encode("utf-8")
+    id = hashlib.md5(json_bytes).hexdigest()
+
+    pydeck_proto.json = pydeck_json
+    pydeck_proto.use_container_width = use_container_width
+
+    pydeck_proto.id = id

lib/tests/streamlit/elements/map_test.py

@@ -382,3 +382,14 @@ def test_pyspark_dataframe(self):
 
         """Check if map data has 5 rows"""
         self.assertEqual(len(c["layers"][0]["data"]), 5)
+
+    def test_id_changes_when_data_changes(self):
+        st.map()
+
+        orig_id = self.get_delta_from_queue().new_element.deck_gl_json_chart.id
+        np.random.seed(0)
+
+        df = pd.DataFrame({"lat": [1, 2, 3, 4], "lon": [10, 20, 30, 40]})
+        st.map(df)
+        new_id = self.get_delta_from_queue().new_element.deck_gl_json_chart.id
+        self.assertNotEquals(orig_id, new_id)