Node.js CRUD API

I have been wanting to check out Node for quite a while now. I am used to the more common OS thread-based concurrency model that we see in Java application servers. Node is instead based on an event-driven, non-blocking I/O model where all connections are handled in one thread.¹ As long as the processing for each request is not CPU-intensive, it can handle thousands of concurrent requests.²

Another more obvious advantage of Node is that your application is written in Javascript. Anyone who has ever written client-side Javascript can immediately begin writing server-side code. You could also, for example, use the same input validation code in your client and server.³

Setup

Never having written a Node app before, I based my first one largely off this great blog Creating a REST API using Node.js, Express, and MongoDB by Christophe Coenraets. I hope to explore MongoDB more in another post. For now I will ignore it and just say that it is simple to install and Chritophe's code to talk to it works as is.

I ran my app on Windows and I did get tripped up on installing the Node MongoDB driver with npm. I had to follow these steps and run "set npm_config_arch=x86" before running "npm mongodb".

The Code

The server is pretty straightforward. Map each of your routes to a function that handles the request and listen on a specific port.

I updated the functions that talk to MongoDB to (I think) be more RESTful.⁴ The non-GET requests will respond with more meaningful HTTP response codes instead of JSON.

Node is able to handle multiple connections in one thread because of the use of callbacks. Any time you do something in your app that may take a long time you, tell Node what to do and provide a function to call when it is finished. It can handle other requests while the long running operation (like reading a file) is completing.

Testing

Bringing in a testing framework would probably be overkill for this simple app, so cURL will suffice. I got it for Windows here. An example for each of the routes:

curl -i -X GET http://localhost:3000/wines
curl -i -X GET http://localhost:3000/wines/<id>
curl -i -X DELETE http://localhost:3000/wines/<id>
curl -i -X POST -H "Content-Type: application/json" -d @new-wine.json http://localhost:3000/wines
curl -i -X PUT -H "Content-Type: application/json" -d @new-wine.json http://localhost:3000/wines/<id>

1 http://nodejs.org/

2 http://blog.caustik.com/2012/08/19/node-js-w1m-concurrent-connections/

3 http://www.theprojectspot.com/tutorial-post/nodejs-for-beginners-callbacks/4

4 http://williamdurand.fr/2012/08/02/rest-apis-with-symfony2-the-right-way/