// these modules need to be imported in order to use them.
// Node has several modules. They are like any #include
// or import statement in other languages
var http = require("http");
var url = require("url");
// The most important line in any Node file. This function
// does the actual process of creating the server. Technically,
// Node tells the underlying operating system that whenever a
// connection is made, this particular callback function should be
// executed. Since we're creating a web service with REST API,
// we want an HTTP server, which requires the http variable
// we created in the lines above.
// Finally, you can see that the callback method receives a 'request'
// and 'response' object automatically. This should be familiar
// to any PHP or Java programmer.
http.createServer(function(request, response) {
// The response needs to handle all the headers, and the return codes
// These types of things are handled automatically in server programs
// like Apache and Tomcat, but Node requires everything to be done yourself
response.writeHead(200, {"Content-Type": "text/plain"});
// Here is some unique-looking code. This is how Node retrives
// parameters passed in from client requests. The url module
// handles all these functions. The parse function
// deconstructs the URL, and places the query key-values in the
// query object. We can find the value for the "number" key
// by referencing it directly - the beauty of JavaScript.
var params = url.parse(request.url, true).query;
var input = params.number;
// These are the generic JavaScript methods that will create
// our random number that gets passed back to the caller
var numInput = new Number(input);
var numOutput = new Number(Math.random() * numInput).toFixed(0);
// Write the random number to response
response.write(numOutput);
// Node requires us to explicitly end this connection. This is because
// Node allows you to keep a connection open and pass data back and forth,
// though that advanced topic isn't discussed in this article.
response.end();
// When we create the server, we have to explicitly connect the HTTP server to
// a port. Standard HTTP port is 80, so we'll connect it to that one.
}).listen(8081);
// Output a String to the console once the server starts up, letting us know everything
// starts up correctly
console.log("Random Number Generator Running...");
2. 在命令行中运行 node random.js
下面是服务器已经启动并运行时看起来的样子:
node random.js
Random Number Generator Running...
引用