Return proper JSON error when something goes wrong on any endpoint

gns3server/handlers/api/controller/project_handler.py

@@ -231,7 +231,6 @@ class ProjectHandler:
         controller = Controller.instance()
         project = controller.get_project(request.match_info["project_id"])
 
-
         started = False
 
         for data in project.export(include_images=bool(request.GET.get("include_images", "0"))):

gns3server/web/route.py

@@ -161,15 +161,15 @@ class Route(object):
                 if response:
                     return response
 
-                # Non API call
-                if api_version is None or raw is True:
-                    response = Response(request=request, route=route, output_schema=output_schema)
+                try:
+                    # Non API call
+                    if api_version is None or raw is True:
+                        response = Response(request=request, route=route, output_schema=output_schema)
 
-                    yield from func(request, response)
-                    return response
+                        yield from func(request, response)
+                        return response
 
-                # API call
-                try:
+                    # API call
                     if "controller" in func.__module__ and server_config.getboolean("controller", False) is False:
                         raise aiohttp.web.HTTPForbidden(text="The server is not a controller")