用expressjs写RESTful API

expressjs

expressjs是一个基于nodejs的web开发框架：http://expressjs.com/，这篇博客目的就是用expressjs写一个关于products的最简单的RESTful API

一个最简单express的例子

package.json

{
  "name": "hello-world",
  "description": "hello world of express js",
  "version": "0.0.1",
  "private": true,
  "dependencies": {
    "express": "4.4.x"
  }
}

安装express:

npm install

app.js

var express = require('express')

var app = express();

app.get('/hello', function(req, res){
   res.send('hello world')
});

var server = app.listen(3000, function() {
   console.log('listening on port %d', server.address().port);

});

运行:

node app

RESTful API

GET  /products

var express = require('express')
var app = express();

var products = [
   { name: 'apple juice', description: 'good', price: 12.12 },
   { name: 'banana juice', description: 'just so sos', price: 4.50 }
]

app.get('/products', function(req, res) {
   res.json(products);
});

var server = app.listen(3000, function() {
   console.log('listening on port %d', server.address().port);
})

GET /products/:id => 200

app.get('/products/:id', function(req, res) {
   res.json(products[req.params.id]);
})

GET /products/:id => 404

app.get('/products/:id', function(req, res) {
   if (products.length <= req.params.id || req.params.id < 0) {
      res.statusCode = 404;
      return res.send('Error 404: No products found')
   }
   res.json(products[req.params.id]);
})

POST /products => 201

因为我们在接受POST请求的时候，需要解析POST的body，所以，我们就要使用middleware来做这件事情，在早期版本中提供了bodyParser这样的方式。但是这种方式会创建大量的临时文件。所以，我们应该直接使用json或者urlencoded这样的middleware直接解析

在package.json中添加依赖：

    "body-parser": "1.4.3"

var express = require('express'),
   bodyParser = require('body-parser')

var app = express()
   .use(bodyParser.json());

app.post('/products', function(req, res) {
   var newProduct = {
      name: req.param('name'),
      description: req.param('description'),
      price: req.param('price')
   }

   products.push(newProduct);
   res.statusCode = 201;
   res.location('/products/' + products.length);
   res.json(true);
});

POST /products => 400

app.post('/products', function(req, res) {
   if (typeof req.param('name') === "undefined" ||
      typeof req.param('description') === "undefined" ||
      typeof req.param('price') === "undefined") {
      res.statusCode = 400;
      res.send('Error 400: products properties missing');
   }
   //......
});

参考资料：

http://blog.modulus.io/nodejs-and-express-create-rest-api

http://erichonorez.wordpress.com/2013/02/10/how-create-a-rest-api-with-node-js-and-express/

http://andrewkelley.me/post/do-not-use-bodyparser-with-express-js.html

http://hawkee.com/snippet/10141/

https://github.com/expressjs/body-parser