# teaching machines

## CS 268: Lecture 17 – Hello, Express

Dear students:

Many websites pull down data from web services, just as we did with the News API. But how are these web services made exactly? That’s what we explore in this lecture. We’ll use Express to create our own web service that responds to HTTP requests and serves back its data through JSON. We’ll also see more advanced uses of the fetch function and overcome an issue of multi-server resource sharing.

• Watch this video, in which we start making a RESTful web service.
• Watch this video, in which we tackle the CORS problem.
• Watch this video, in which we add more endpoints to our service.
• You are encouraged to post a reply in the lecture 17 thread with one of the following:
• A question regarding Express or web services. This might be a question you really don’t know the answer to or one that you do know the answer to and are putting forward as a challenge to your peers.
• An answer to a previously posted question or challenge.
Your participation in this thread is not graded. I include it so that we can maintain some real human interaction.

See you next time.

Sincerely,