Add handling of an impossible path: the view returns a status 204 and…

… the js does not attempt to display the path

geotrek/core/path_router.py

@@ -150,6 +150,8 @@ def get_edge_weight(self, edge_id):
     def get_route(self, steps):
         self.steps = steps
         line_strings = self.compute_list_of_paths()
+        if line_strings is None:
+            return None
 
         multi_line_string = GeometryCollection(line_strings, srid=settings.SRID)
         multi_line_string.transform(settings.API_SRID)
@@ -164,6 +166,8 @@ def compute_list_of_paths(self):
             from_step = self.steps[i]
             to_step = self.steps[i + 1]
             line_strings = self.compute_two_steps_line_strings(from_step, to_step)
+            if line_strings is None:
+                return None
             merged_line_string = self.merge_line_strings(line_strings)
             all_line_strings.append(merged_line_string)
         return all_line_strings
@@ -174,6 +178,8 @@ def compute_two_steps_line_strings(self, from_step, to_step):
 
         shortest_path = self.get_shortest_path(from_node_info['node_id'],
                                                to_node_info['node_id'])
+        if shortest_path is None:
+            return None
         line_strings = self.node_list_to_line_strings(shortest_path,
                                                       from_node_info, to_node_info)
 
@@ -409,6 +415,9 @@ def get_node_id_per_idx(node_idx):
         current_node_id, current_node_idx = to_node_id, to_node_idx
         path = [current_node_id]
         while current_node_id != from_node_id:
+            if current_node_idx < 0:
+                # The path ends here but this node is not the destination
+                return None
             current_node_idx = predecessors[current_node_idx]
             current_node_id = get_node_id_per_idx(current_node_idx)
             path.append(current_node_id)

geotrek/core/static/core/multipath.js

@@ -505,11 +505,17 @@ L.Handler.MultiPath = L.Handler.extend({
                     steps: sent_steps,
                 })
             })
-            .then(response => response.json())
+            .then(response => {
+                // console.log("response", response)
+                if (response.status == 200)
+                    return response.json()
+            })
             .then(data => {
-                console.log('response:', data)
-                var route = {'geojson': data}
-                this.fire('fetched_route', route);
+                // console.log('response data:', data)
+                if (data) {
+                    var route = {'geojson': data}
+                    this.fire('fetched_route', route);
+                }
             })
             // .catch(e => {
             //     console.log("fetchRoute", e)

geotrek/core/views.py

@@ -326,7 +326,9 @@ def route_geometry(self, request, *args, **kwargs):
 
         try:
             path_router = PathRouter()
-            response, status = path_router.get_route(steps), 200
+            response = path_router.get_route(steps)
+            status = 200 if response is not None else 204
+
         except Exception as exc:
             response, status = {'error': '%s' % exc, }, 500
         return Response(response, status)