Using QGIS actions to add buildings from OpenStreetMap to a map

# Import the necessary packages
import requests
import json
from qgis.core import Qgis, QgsVectorLayer, QgsJsonUtils, QgsProject

# Get the coordinates of the point you clicked on in the map.  The parts between [% %] are QGIS Expressions. Those work the same as if you would use them in the Field Calculator.  Python interprets it as the resulting value.
pointxy = "[%replace(to_string(x(transform($geometry, @layer_crs ,'EPSG:4326'))),',','.')%],[%replace( to_string(y(transform($geometry, @layer_crs ,'EPSG:4326'))),',','.')%]"

# The parameters of the request to the API. Replace MY_API_KEY with your own key, that you can get at https://buntinglabs.com/solutions/openstreetmap-extracts.  We request all buildings within a radius of 100 meter around the current point.
params = {
  "tags": "building=*",
  "api_key": "MY_API_KEY",
  "center": pointxy,
  "radius": "100"
}

# Make the request to the extract-in-radius endpoint of the API
response = requests.get("https://osm.buntinglabs.com/v1/osm/extract-in-radius", params=params)

# Convert the response to a JSON string
geoj = json.dumps(response.json())

# Find the attribute fields in the GeoJSON 
fields = QgsJsonUtils.stringToFields(geoj)

# Get the features from the GeoJSON and use the previously found attribute fields
feats = QgsJsonUtils.stringToFeatureList(geoj,fields, None)

# If the API returns 1 or more features, execute the code below else print a message to the console log
if len(feats) > 0:
    # Get the geometry type of the result of the request.  For our buildings example it will always be a Multipolygon, but if you request something else from the API, it could be another type.
    geom_type = feats[0].geometry().type()
    if geom_type == QgsWkbTypes.PointGeometry:
        geotype = "MultiPoint"
    elif geom_type == QgsWkbTypes.LineGeometry:
        geotype = "MultiLineString"
    elif geom_type == QgsWkbTypes.PolygonGeometry:
        geotype = "MultiPolygon"
    else:
        print("geometry type not defined in the result")
    
    # Create an empty Temporary Scratch Layer called "Buildings" of the previously found geometry type
    layer = QgsVectorLayer(geotype, "Buildings", "memory")
    # Add the attribute fields to the Temporary Scratch Layer
    layer.dataProvider().addAttributes(fields)
    # Add the empty Temporary Scratch Layer to the map 
    registry = QgsProject.instance()
    registry.addMapLayer(layer)
    # Add each feature from the API request to the Temporary Scratch Layer
    for feature in feats:
        layer.dataProvider().addFeatures([feature])
else:
    print("no features found in the geoJSON")   

# Reload the visualisation of the Temporary Scratch Layer
layer.updateExtents()
layer.reload()