目录

• Express 框架核心特性：
• Express安装
• 方式一：安装express-generator
• 创建项目
• 项目目录如下
• 方式二： 自己搭建环境
• express 初体验
• 请求和响应
• 返回数据
• Express 中间件
• 认识中间件
• 中间是什么？
• 中间件中可以执行哪些任务？
• 使用中间件
• 日志记录中间件
• 上传文件中间件
• 请求和响应
• 请求解析
• 方式一：params
  
• 方式二：query
  
• 方式三：通过post请求中的body的json格式；
  
• 方式四：通过post请求中
• 方式五：通过post请求中的form-data格式；
  
• 响应方式
• 路由的使用
• 静态资源服务器
• 错误处理方式

npm install -g express-generator

express express-app

npm install 
node bin/www
node app.js   

npm init -y

npm install express

const express = require(''express'');
// 创建服务器
const app = express();
app.get(''/'',(req,res) => {
  res.end("Hello World");
});
app.listen(8000,() => {
  console.log("服务器启动成功~");
})

node app.js

const express = require(''express'');
const app = express();
app.get(''/users/:userId'', (req, res, next) => {
  console.log(req.params.userId);
  res.json({username: "liyingxia", password: "8i8i8i8i" });
});
app.listen(8000, () => {
  console.log("静态服务器启动成功~");
})

// express 中间件的使用
const express = require(''express'');
const res = require(''express/lib/response'');
const app = express();
app.use((req,res,next) => {
  console.log("middleware");
  next();
});
app.use((req,res,next) => {
  console.log("middleware");
  res.end("Hello Common Middleware");
})
app.listen(9000,()=>{
  console.log("中间件服务器启动成功~")
})

//path 路径匹配中间件
app.use(''/home'',(req,res,next) => {
  console.log("home middleware 中间件");
  next();
});
app.use(''/home'',(req,res,next) => {
  console.log("home middleware02");
  next();
  res.end("middleware");
});
app.use((req,res,next) =>{
   console.log("middleware");
})

// path 和 method 匹配中间件
app.get(''/home'',(req,res,next) => {
  console.log("home get middleware");
  next();
})
app.post(''/login'',(req,res,next) => {
  console.log("login post middleware");
  next();
});
app.use((req,res,next) => {
  console.log("common middleware");
})
app.use(express.json());
app.use(express.urlencoded({extended:true}));
app.post(''/login'',(req,res,next) => {
  console.log(req.body);
  res.end("登陆成功~");
});

npm install morgan

const loggerWriter = fs.createWriteStream(''./log/access.log'', {
  flags: ''a+''
})
app.use(morgan(''combined'', {stream: loggerWriter}));

npm install multer

const upload = multer({
  dest: "uploads/"
})

app.post(''/upload'', upload.single(''file''), (req, res, next) => {
  console.log(req.file.buffer);
  res.end("文件上传成功~");
})

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, "uploads/")
  },
  filename: (req, file, cb) => {
    cb(null, Date.now() + path.extname(file.originalname));
  }
})
const upload = multer({
  storage
})
app.post(''/upload'', upload.single(''file''), (req, res, next) => {
  console.log(req.file.buffer);
  res.end("文件上传成功~");
})

app.use(''/upload'', upload.array(''files''), (req, res, next) => {
  console.log(req.files);
});

app.use(''/login/:id/:name'', (req, res, next) => {
  console.log(req.params);
  res.json("请求成功~");
})

app.use(''/login'', (req, res, next) => {
  console.log(req.query);
  res.json("请求成功~");
})

app.use((req, res, next) => {
  if (req.headers[''content-type''] === ''application/json'') {
    req.on(''data'', (data) => {
      const userInfo = JSON.parse(data.toString());
      req.body = userInfo;
    })
    req.on(''end'', () => {
      next();
    })
  } else {
    next();
  }
})
app.post(''/login'', (req, res, next) => {
  console.log(req.body);
  res.end("登录成功~");
});

app.use(express.json());
app.post(''/login'', (req, res, next) => {
  console.log(req.body);
  res.end("登录成功~");
});

app.use(express.json());
app.use(express.urlencoded({extended: true}));

app.post(''/login'', (req, res, next) => {
  console.log(req.body);
  res.end("登录成功~");
});

app.use(upload.any());
app.use(''/login'', (req, res, next) => {
  console.log(req.body);
});

res.end("获取成功~")

res.json({name:"liyignxia",password:"123456"});

res.status(200);

// 用户相关的处理
const userRouter = express.Router();

userRouter.get(''/'', (req, res, next) => {
  res.end("用户列表");
});

userRouter.post(''/'', (req, res, next) => {
  res.end("创建用户");
});

userRouter.delete(''/'', (req, res, next) => {
  res.end("删除用户");
});

app.use(''/users'', userRouter);

const express = require(''express'');
const app = express();
app.use(express.static(''./build''));
app.listen(8000, () => {
  console.log("静态服务器启动成功~");
})

app.use((req, res, next) => {
  next(new Error("USER DOES NOT EXISTS"));
});
app.use((err, req, res, next) => {
  const message = err.message;
  switch (message) {
    case "USER DOES NOT EXISTS":
      res.status(400).json({message})
  }
  res.status(500)
})

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yum -y install gcc make gcc-c++ openssl-devel wget

wget http://nodejs.org/dist/v0.12.7/node-v0.12.7.tar.gz
tar -zvxf node-v0.12.7.tar.gz

cd node-v0.
./configure
make install

node -v

npm install express -g

express demo1

cd demo1
npm install

node start

npm install -g express-generator

/tmp mkdir express-demo
  /tmp cd express-demo 
  express-demo express

   create : .
   create : ./package.json
   create : ./app.js
   create : ./public
   create : ./public/javascripts
   create : ./public/images
   create : ./public/stylesheets
   create : ./public/stylesheets/style.css
   create : ./routes
   create : ./routes/index.js
   create : ./routes/users.js
   create : ./views
   create : ./views/index.jade
   create : ./views/layout.jade
   create : ./views/error.jade
   create : ./bin
   create : ./bin/www

   install dependencies:
     $ cd . && npm install

   run the app:
     $ DEBUG=express-demo:* npm start

npm install

express-demo  npm start

> ex1@0.0.0 start /private/tmp/ex1
> node ./bin/www