ExpressJS - RESTful API

REST是 Roy Fielding 在2000年的Paper Fielding论文中提出的，RESTful URI和方法为无涯教程提供了处理请求所需的几乎所有信息。下表列出了应如何使用各种动词以及如何命名URI，将在最后创建一个 movies API；

现在在Express中创建此API。像下面的程序一样，将 index.js 文件替换为 movies.js 文件。

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());

//需要我们在movies.js中定义的Router
var movies=require('./movies.js');

//在子路由 /movies 上使用路由器
app.use('/movies', movies);

app.listen(3000);

首先设置movies.js文件，不是使用数据库来存储电影，而是将它们存储在内存中，因此，每次服务器重新启动时，添加的电影都会消失。可以使用数据库或文件(使用节点fs模块)轻松地模拟它。

导入Express之后，创建一个路由器并使用 module.exports 将其导出-

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 here
module.exports=router;

GET 路由

定义获取所有电影的GET路由-

router.get('/', function(req, res){
   res.json(movies);
});

要测试是否正常，请运行您的应用，然后打开终端并输入-

curl -i -H "Accept: application/json" -H "Content-Type: application/json" -X GET 
localhost:3000/movies

将显示以下响应-

[{"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}]

现在让无涯教程创建一条通过ID来获取特定电影的路由。

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"});
   }
});

这将根据提供的ID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

您将获得以下响应-

{"id":101,"name":"Fight Club","year":1999,"rating":8.1}

POST 路由

使用以下路由来处理 POST 数据-

router.post('/', function(req, res){
   //检查是否提供了所有字段并且是否有效：
   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});
   }
});

这将创建一个新电影并将其存储在movie变量中。要检查此路由，请在终端中输入以下代码-

链接：https://www.learnfk.comhttps://www.learnfk.com/expressjs/expressjs-restful-apis.html

来源：LearnFk无涯教程网

curl -X POST --data "name=Toy%20story&year=1995&rating=8.5" http://localhost:3000/movies

将显示以下响应-

{"message":"New movie created.","location":"/movies/105"}

要测试是否已将其添加到movie对象，请再次运行/movies/105的get请求。 将显示以下响应-

{"id":105,"name":"Toy story","year":"1995","rating":"8.5"}

PUT 路由

PUT路由与POST路由几乎相同，无涯教程将为将要updated/created的对象指定ID， 通过以下方式创建路由。

无涯教程网

router.put('/:id', function(req, res){
   //检查是否提供了所有字段并且是否有效：
   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 {
      //获取给定 id 的电影索引。
      var updateIndex=movies.map(function(movie){
         return movie.id;
      }).indexOf(parseInt(req.params.id));
      
      if(updateIndex === -1){
         //找不到电影，新建
         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 {
         //更新现有电影
         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函数，如果存在，它将更新对象，如果不存在，它将创建一个新对象，要创建新的电影，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

响应

{"message":"Movie id 101 updated.","location":"/movies/101"}

DELETE 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); //获取给定 id 的电影索引。
   
   if(removeIndex === -1){
      res.json({message: "Not found"});
   } else {
      movies.splice(removeIndex, 1);
      res.send({message: "Movie id " + req.params.id + " removed."});
   }
});

以与检查其他路由相同的方式检查路由。成功删除后(如id 105)，您将获得以下输出-

{message: "Movie id 105 removed."}

最后，无涯教程的 movies.js 文件将如下所示。

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);  //由于找不到电影，因此将状态设置为 404
      res.json({message: "Not Found"});
   }
});
router.post('/', function(req, res){
   //检查是否提供了所有字段并且是否有效：
   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) {
   //检查是否提供了所有字段并且是否有效：
   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 {
      //检查是否提供了所有字段并且是否有效：
      var updateIndex=movies.map(function(movie){
         return movie.id;
      }).indexOf(parseInt(req.params.id));
      
      if(updateIndex === -1){
         //找不到电影，新建
         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 {
         //更新现有电影
         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); //获取给定 id 的电影索引。
   
   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;

这样就完成了无涯教程的REST API。现在，您可以使用此简单的体系结构样式和Express创建更复杂的应用程序。