创建移动应用程序，单页面应用程序，使用AJAX调用以及向客户端提供数据始终需要API.如何构造和命名这些API和端点的流行架构风格称为 REST(代表性传输状态). HTTP 1.1 的设计考虑了REST原则. REST由 Roy Fielding 于2000年在他的Paper Fielding Dissertations中介绍.
RESTful URI和方法为我们提供了处理请求所需的几乎所有信息.下面给出的表总结了如何使用各种动词以及如何命名URI.我们将在最后创建一个电影API;现在让我们讨论一下它的结构.
现在让我们在Express中创建此API.我们将使用JSON作为传输数据格式，因为它易于在JavaScript中使用并具有其他好处.将 index.js 文件替换为 movies.js 文件，如以下程序所示.
index.js
var express = require('express');var bodyParser = require('body-parser');var multer = require('multer');var upload = multer();var app = express();app.use(cookieParser());app.use(bodyParser.json());app.use(bodyParser.urlencoded({ extended: true }));app.use(upload.array());//Require the Router we defined in movies.jsvar movies = require('./movies.js');//Use the Router on the sub route /moviesapp.use('/movies', movies);app.listen(3000);现在我们已经设置了应用程序，让我们专注于创建API.
首先设置movies.js文件.我们没有使用数据库存储电影，而是将它们存储在内存中;所以每次服务器重启时，我们添加的电影都会消失.这可以使用数据库或文件(使用节点fs模块)轻松模仿.
导入Express后，创建路由器并使用 module.exports :
var express = require('express');var router = express.Router();var movies = [ {id: 101, name: "Fight Club", year: 1999, rating: 8.1}, {id: 102, name: "Inception", year: 2010, rating: 8.7}, {id: 103, name: "The Dark Knight", year: 2008, rating: 9}, {id: 104, name: "12 Angry Men", year: 1957, rating: 8.9}];//Routes will go heremodule.exports = router;获取路线
让我们定义获取所有电影和减去的GET路线;
router.get('/', function(req, res){ res.json(movies);});要测试这是否正常，请运行您的应用，然后打开您的终端并输入 :
curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET localhost:3000/movies
以下回复将显示 :
[{"id":101,"name":"Fight Club","year":1999,"rating":8.1},{"id":102,"name":"Inception","year":2010,"rating":8.7},{"id":103,"name":"The Dark Knight","year":2008,"rating":9},{"id":104,"name":"12 Angry Men","year":1957,"rating":8.9}]我们有一条路线可以获得所有电影.现在让我们创建一个通过其ID获取特定电影的路线.
router.get('/:id([0-9]{3,})', function(req, res){ var currMovie = movies.filter(function(movie){ if(movie.id == req.params.id){ return true; } }); if(currMovie.length == 1){ res.json(currMovie[0]) } else { res.status(404);//Set status to 404 as movie was not found res.json({message: "Not Found"}); }});这将根据我们提供的身份证件获取电影.要检查输出，请在终端中使用以下命令 :
curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET localhost:3000/movies/101
您将得到以下回复 :
{"id":101，"name":"Fight Club"，"year":1999，"rating":8.1}如果您访问的路线无效，则会产生无法获取错误，而如果您访问的ID有效且无效如果存在，它将产生404错误.
我们完成了GET路线，现在让我们转到 POST 路线.
POST路线
使用以下路线处理 POSTed 数据 :
router.post('/', function(req, res){ //Check if all fields are provided and are valid: if(!req.body.name || !req.body.year.toString().match(/^[0-9]{4}$/g) || !req.body.rating.toString().match(/^[0-9]\.[0-9]$/g)){ res.status(400); res.json({message: "Bad Request"}); } else { var newId = movies[movies.length-1].id+1; movies.push({ id: newId, name: req.body.name, year: req.body.year, rating: req.body.rating }); res.json({message: "New movie created.", location: "/movies/" + newId}); }});这将创建一部新电影并将其存储在电影变量中.要检查此路线，请在您的终端输入以下代码 :
curl -X POST --data "name = Toy%20story&year = 1995&rating = 8.5" http://localhost:3000/movies
以下回复将显示 :
{"message":"New movie created.","location":"/movies/105"}要测试是否已将其添加到电影对象，请再次运行/movies/105 的获取请求.以下回复将显示 :
{"id":105,"name":"Toy story","year":"1995","rating":"8.5"}让我们继续创建PUT和DELETE路线.
PUT路径
PUT路由几乎与POST路由相同.我们将指定要更新/创建的对象的id.按以下方式创建路线.
router.put('/:id', function(req, res){ //Check if all fields are provided and are valid: if(!req.body.name || !req.body.year.toString().match(/^[0-9]{4}$/g) || !req.body.rating.toString().match(/^[0-9]\.[0-9]$/g) || !req.params.id.toString().match(/^[0-9]{3,}$/g)){ res.status(400); res.json({message: "Bad Request"}); } else { //Gets us the index of movie with given id. var updateIndex = movies.map(function(movie){ return movie.id; }).indexOf(parseInt(req.params.id)); if(updateIndex === -1){ //Movie not found, create new movies.push({ id: req.params.id, name: req.body.name, year: req.body.year, rating: req.body.rating }); res.json({message: "New movie created.", location: "/movies/" + req.params.id}); } else { //Update existing movie movies[updateIndex] = { id: req.params.id, name: req.body.name, year: req.body.year, rating: req.body.rating }; res.json({message: "Movie id " + req.params.id + " updated.", location: "/movies/" + req.params.id}); } }});此路由将执行上表中指定的功能.如果对象存在，它将使用新的详细信息更新对象.如果它不存在，它将创建一个新对象.要检查路由，请使用以下curl命令.这将更新现有的电影.要创建新电影，只需将ID更改为不存在的ID.
curl -X PUT --data "name = Toy%20story&year = 1995&rating = 8.5" http://localhost:3000/movies/101
回复
{"message":"Movie id 101 updated.","location":"/movies/101"}删除路由
使用以下代码创建删除路由. :
router.delete('/:id', function(req, res){ var removeIndex = movies.map(function(movie){ return movie.id; }).indexOf(req.params.id); //Gets us the index of movie with given id. if(removeIndex === -1){ res.json({message: "Not found"}); } else { movies.splice(removeIndex, 1); res.send({message: "Movie id " + req.params.id + " removed."}); }});检查路线的方式与检查其他路线的方式相同.成功删除后(例如id 105)，您将获得以下输出 :
{message:"Movie id 105 removed."}最后，我们的 movies.js 文件如下所示.
var express = require('express');var router = express.Router();var movies = [ {id: 101, name: "Fight Club", year: 1999, rating: 8.1}, {id: 102, name: "Inception", year: 2010, rating: 8.7}, {id: 103, name: "The Dark Knight", year: 2008, rating: 9}, {id: 104, name: "12 Angry Men", year: 1957, rating: 8.9}];router.get('/:id([0-9]{3,})', function(req, res){ var currMovie = movies.filter(function(movie){ if(movie.id == req.params.id){ return true; } }); if(currMovie.length == 1){ res.json(currMovie[0]) } else { res.status(404); //Set status to 404 as movie was not found res.json({message: "Not Found"}); }});router.post('/', function(req, res){ //Check if all fields are provided and are valid: if(!req.body.name || !req.body.year.toString().match(/^[0-9]{4}$/g) || !req.body.rating.toString().match(/^[0-9]\.[0-9]$/g)){ res.status(400); res.json({message: "Bad Request"}); } else { var newId = movies[movies.length-1].id+1; movies.push({ id: newId, name: req.body.name, year: req.body.year, rating: req.body.rating }); res.json({message: "New movie created.", location: "/movies/" + newId}); }});router.put('/:id', function(req, res) { //Check if all fields are provided and are valid: if(!req.body.name || !req.body.year.toString().match(/^[0-9]{4}$/g) || !req.body.rating.toString().match(/^[0-9]\.[0-9]$/g) || !req.params.id.toString().match(/^[0-9]{3,}$/g)){ res.status(400); res.json({message: "Bad Request"}); } else { //Gets us the index of movie with given id. var updateIndex = movies.map(function(movie){ return movie.id; }).indexOf(parseInt(req.params.id)); if(updateIndex === -1){ //Movie not found, create new movies.push({ id: req.params.id, name: req.body.name, year: req.body.year, rating: req.body.rating }); res.json({ message: "New movie created.", location: "/movies/" + req.params.id}); } else { //Update existing movie movies[updateIndex] = { id: req.params.id, name: req.body.name, year: req.body.year, rating: req.body.rating }; res.json({message: "Movie id " + req.params.id + " updated.", location: "/movies/" + req.params.id}); } }});router.delete('/:id', function(req, res){ var removeIndex = movies.map(function(movie){ return movie.id; }).indexOf(req.params.id); //Gets us the index of movie with given id. if(removeIndex === -1){ res.json({message: "Not found"}); } else { movies.splice(removeIndex, 1); res.send({message: "Movie id " + req.params.id + " removed."}); }});module.exports = router;这样就完成了我们的REST API.现在，您可以使用这种简单的架构风格和Express创建更复杂的应用程序.