A web service that draw a map to be called using LOAD web2py helper

map_service.py

@service.run
def getmap(conn, tablename, the_geom="geom", bbox=''):
    """ """
    session.forget(response)
    js = """
var url = "%(url)s";
var gargs = "%(bbox)s" && '?bbox='+"%(bbox)s";
var dynSource = new ol.source.Vector({
  url: url + gargs,
  format: new ol.format.GeoJSON(),
  loader: function(extent, resolution, projection) {
    $.ajax({
      url: url + '?bbox=' + extent.join(','),
      success: function(data) {
        if (data.features.length>0) {
            dynSource.addFeatures(dynSource.getFormat().readFeatures(data));
        }
      }
    });
  },
  projection: 'EPSG:3857',
  strategy: ol.loadingstrategy.bbox
});
var map = new ol.Map({
    "target": "map",
    "layers": [
        new ol.layer.Tile({opacity: 0.3, source: new ol.source.OSM()}),
        new ol.layer.Vector({"source": dynSource})
    ],
    view: new ol.View({
      center: [0, 0],
      zoom: 2
    })
});
function fitmap (mymap) {
    if ( Number.isFinite(dynSource.getExtent()[0])!==false ) {
        mymap.getView().fit(dynSource.getExtent(), mymap.getSize())
    } else {
        setTimeout(function () {fitmap(mymap)}, 500)
    };
}
fitmap(map);
    """ % dict(
        url = URL("default", "call", args=("run", "geom", conn, tablename, the_geom,)),
        bbox = bbox
    )

    response.js = jsmin(js)
    return DIV(_id="map", _style="height: 500px;")