攔截器可以根據需要 做權限攔截 登錄只是權限的一種，

思路是req.session.user判斷用戶session是否存在，是否是需要攔截的地址，

如果是就跳轉登錄頁，或其他頁，

如果非需攔截頁，則執行 next(); 放行

因為是順序執行的所以 app.all(‘/*‘, function(req, res, next){ 這個方法需放在定義的路由之上

具體寫法如下：

//登錄攔截器
app.all(‘/*‘, function(req, res, next){
  if (req.session.user) {
    next();
  }else {
    var
 
 arr = req.url.split(‘/‘);// 解析用戶請求的路徑

    for (var i = 0, length = arr.length; i < length; i++) {// 去除 GET 請求路徑上攜帶的參數
      arr[i] = arr[i].split(‘?‘)[0];
    }
    if (arr.length > 1 && arr[1] == ‘‘) {// 判斷請求路徑是否為根、登錄、註冊、登出，如果是不做攔截
      next();
    } else if (arr.length > 2 && arr[1] == ‘user‘ && (arr[2] == ‘register‘ || arr[2] == ‘login‘ || arr[2] == ‘logout‘ || arr[2].indexOf(‘login‘) > 0 )) {
      next();
    } 
 
else {  // 登錄攔截
      req.session.originalUrl = req.originalUrl ? req.originalUrl : null;  // 記錄用戶原始請求路徑
      req.flash(‘error‘, ‘請先登錄‘);
      res.redirect(‘/user/login‘);  // 將用戶重定向到登錄頁面
    }
  }
});

結尾附上我的app.js：

var express = require(‘express‘);
var path = require(‘path‘);
var favicon = require(‘serve-favicon‘);
 
var logger = require(‘morgan‘);
var cookieParser = require(‘cookie-parser‘);
var session = require(‘express-session‘);
var bodyParser = require(‘body-parser‘);
var hbs = require(‘hbs‘);
var flash = require(‘connect-flash‘);

var index = require(‘./routes/index‘);
var users = require(‘./routes/users‘);
var about = require(‘./routes/about‘);
var list_ = require(‘./routes/product/list‘);
var login = require(‘./routes/user/login‘);
var login_post = require(‘./routes/user/login_post‘);

var app = express();

app.use(cookieParser());
app.use(session({
  secret: ‘123456‘,
  cookie: {maxAge: 60 * 1000 * 30},
  resave: false,
  saveUninitialized: true
}));

app.use(flash());

hbs.registerPartials(path.join(__dirname, ‘views‘, ‘partials‘ ));
// view engine setup
app.set(‘views‘, path.join(__dirname, ‘views‘));
app.set(‘view engine‘, ‘hbs‘);

var blocks = {};

hbs.registerHelper(‘extend‘, function(name, context) {
  var block = blocks[name];
  if (!block) {
    block = blocks[name] = [];
  }

  block.push(context.fn(this)); // for older versions of handlebars, use block.push(context(this));
});

hbs.registerHelper(‘block‘, function(name) {
  var val = (blocks[name] || []).join(‘\n‘);

  // clear the block
  blocks[name] = [];
  return val;
});

// uncomment after placing your favicon in /public
app.use(favicon(path.join(__dirname, ‘public‘, ‘favicon.ico‘)));
app.use(logger(‘dev‘));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, ‘public‘)));

//登錄攔截器
app.all(‘/*‘, function(req, res, next){
  if (req.session.user) {
    next();
  }else {
    var arr = req.url.split(‘/‘);// 解析用戶請求的路徑

    for (var i = 0, length = arr.length; i < length; i++) {// 去除 GET 請求路徑上攜帶的參數
      arr[i] = arr[i].split(‘?‘)[0];
    }
    if (arr.length > 1 && arr[1] == ‘‘) {// 判斷請求路徑是否為根、登錄、註冊、登出，如果是不做攔截
      next();
    } else if (arr.length > 2 && arr[1] == ‘user‘ && (arr[2] == ‘register‘ || arr[2] == ‘login‘ || arr[2] == ‘logout‘ || arr[2].indexOf(‘login‘) >= 0 )) {
      next();
    } else {  // 登錄攔截
      req.session.originalUrl = req.originalUrl ? req.originalUrl : null;  // 記錄用戶原始請求路徑
      req.flash(‘error‘, ‘請先登錄‘);
      res.redirect(‘/user/login‘);  // 將用戶重定向到登錄頁面
    }
  }
});

app.use(‘/‘, index);
app.use(‘/users‘, users);
app.use(‘/about‘, about);
app.use(‘/product/list‘, list_);
app.use(‘/user/login‘, login);
app.use(‘/user/loginPost‘, login_post);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error(‘Not Found‘);
  err.status = 404;
  next(err);
});

// error handler
app.use(function(err, req, res, next) {
// set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get(‘env‘) === ‘development‘ ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render(‘error‘);
});

module.exports = app;

node + express 登錄攔截器