TypeError: Cannot read property 'length' of undefined about kong-oauth2-hello-world

[kele1997]

I met the same issue.
To sovle this, you need to know two things:

1. this app will send request to kong admin api, but this request is not send from the app's ip, but your browser's ip, so make sure your browser can send request to kong admin api successfully.
2. maybe you use the lastest kong , and this app seems does't update in time. so you can modify it by your self.

before modify

kong-oauth2-hello-world/app.js

Lines 70 to 76 in 4ffe961

	if (json_response.data.length == 1) {
	application_name = json_response.data[0].name;
	}
	}
	callback(application_name);
	});
	}

after modify

   if (json_response.data.length == 1) { 
+        console.log(json_response); // print json_response, if json_response =='{"message":"not found"}', it seems your browser can't send request to kong admin api
+        application_name = json_response[name];
-        application_name = json_response.data[0].name; 
       } 
     } 
     callback(application_name); 
   }); 
 } 

[josepereira1]

you should check first if json_response.data is not undefined, before invoke length, without this, server can fail:
if (json_response.data && json_response.data.length == 1) { application_name = json_response.data[0].name; }