I am running my web server written in node/locomotive.js on cloud9 terminal. When I try to access it from a client program such as curl, it gets redirected to
https://c9.io/signin.html?redirect=http%3A%2F%2Fchekofvgameserver-c9-linzhp.c9.io%2F
That makes it impossible for any client program to test the server. Access it from a browser works fine, because the browser remembers my cloud9 credentials.
Is there a way to skip the signin page of cloud9?
The problem is that your project is probably a private project. In order to guarantee that only authorized people have access to your running the Cloud9 proxy will intercept calls to your application and check the permissions. If it doesn't find a valid session cookie you will be redirected to the login page. When you use Cloud9 to develop an API server the client will obviously not have that session cookie and fail in the way you described above.
I see two options to work around this: