Implemented the leaflet-realtime plugin

Based on: https://github.com/perliedman/leaflet-realtime

Author: hansthen

folium/plugins/__init__.py

@@ -21,6 +21,7 @@
 from folium.plugins.pattern import CirclePattern, StripePattern
 from folium.plugins.polyline_offset import PolyLineOffset
 from folium.plugins.polyline_text_path import PolyLineTextPath
+from folium.plugins.realtime import Realtime
 from folium.plugins.scroll_zoom_toggler import ScrollZoomToggler
 from folium.plugins.search import Search
 from folium.plugins.semicircle import SemiCircle
@@ -54,6 +55,7 @@
     "MousePosition",
     "PolyLineTextPath",
     "PolyLineOffset",
+    "Realtime",
     "ScrollZoomToggler",
     "Search",
     "SemiCircle",

folium/plugins/realtime.py

@@ -0,0 +1,88 @@
+from branca.element import MacroElement
+from jinja2 import Template
+
+from folium.elements import JSCSSMixin
+from folium.utilities import parse_options, JsCode
+
+
+class Realtime(JSCSSMixin, MacroElement):
+    """Put realtime data on a Leaflet map: live tracking GPS units,
+    sensor data or just about anything.
+
+    Based on: https://github.com/perliedman/leaflet-realtime
+
+    Parameters
+    ----------
+    start : bool, default True
+        Should automatic updates be enabled when layer is added
+        on the map and stopped when layer is removed from the map
+    interval : int, default 60000
+        Automatic update interval, in milliseconds
+    getFeatureId : function, default returns `feature.properties.id`
+        Function to get an identifier uniquely identify a feature over time
+    updateFeature : function
+        Used to update an existing feature's layer;
+        by default, points (markers) are updated, other layers are discarded
+        and replaced with a new, updated layer.
+        Allows to create more complex transitions,
+        for example, when a feature is updated
+    removeMissing : bool, default False
+        Should missing features between updates been automatically
+        removed from the layer
+
+    Other parameters are passed to the GeoJson layer, so you can pass
+        `style`, `pointToLayer` and/or `onEachFeature`.
+
+    Examples
+    --------
+    >>> from folium.utilities import JsCode
+    >>> m = folium.Map()
+    >>> rt = Realtime("https://d2ad6b4ur7yvpq.cloudfront.net/naturalearth-3.3.0/ne_10m_geography_regions_elevation_points.geojson",
+    ...                getFeatureId=JsCode("function(f) { return f.properties.name; }"),
+    ...                interval=10000)
+    >>> rt.add_to(m)
+    """
+
+    _template = Template(
+        """
+        {% macro script(this, kwargs) %}
+            var options = {{this.options|tojson}};
+            {% for key, value in this.functions.items() %}
+            options["{{key}}"] = {{ value }};
+            {% endfor %}
+            var {{ this.get_name() }} = new L.realtime(
+                {{ this.src|tojson }},
+                options
+            );
+            {{ this._parent.get_name() }}.addLayer(
+                {{ this.get_name() }}._container);
+        {% endmacro %}
+    """
+    )
+
+    default_js = [
+        (
+            "Leaflet_Realtime_js",
+            "https://cdnjs.cloudflare.com/ajax/libs/leaflet-realtime/2.2.0/leaflet-realtime.js",  # NoQA
+        )
+    ]
+
+    def __init__(self, src, **kwargs):
+        super().__init__()
+        self._name = "Realtime"
+        self.src = src
+
+        # extract JsCode objects
+        self.functions = {}
+        for key, value in kwargs.items():
+            if isinstance(value, JsCode):
+                self.functions[key] = value.js_code
+
+        # and remove them from kwargs
+        for key in self.functions:
+            kwargs.pop(key)
+
+        # the container is special, as we
+        # do not allow it to be set (yet)
+        # from python
+        self.options = parse_options(container=None, **kwargs)

folium/utilities.py

@@ -410,3 +410,15 @@ def get_and_assert_figure_root(obj: Element) -> Figure:
         figure, Figure
     ), "You cannot render this Element if it is not in a Figure."
     return figure
+
+
+# See:
+# https://github.com/andfanilo/streamlit-echarts/blob/master/streamlit_echarts/frontend/src/utils.js
+# Thanks andfanilo
+class JsCode:
+    def __init__(self, js_code: str):
+        """Wrapper around a js function
+        Args:
+            js_code (str): javascript function code as str
+        """
+        self.js_code = js_code