此示例取自 Node Cookbook，但使用的是 Express 3.1.0：
应用程序.js
var express = require('express')
, routes = require('./routes')
, user = require('./routes/user')
, http = require('http')
, path = require('path');
var app = express();
app.configure(function(){
app.set('port', process.env.PORT || 3000);
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(express.cookieParser('kooBkooCedoN'));
app.use(express.session());
app.use(require('./login'));
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));
});
app.configure('development', function(){
app.use(express.errorHandler());
});
// --------------------------
// MODIFICATION IS MADE HERE!
// --------------------------
app.configure(function(){
app.use(function(req, res, next){
res.locals.user = req.session.user;
next();
});
});
app.get('/', routes.index);
app.post('/', routes.index);
app.del('/', routes.index);
app.get('/:page', routes.index);
http.createServer(app).listen(app.get('port'), function(){
console.log("Express server listening on port " + app.get('port'));
});
我已经按照以下建议对代码进行了一些修改：将 Express.js 2 迁移到 3，特别是 app.dynamicHelpers() 到 app.locals.use？
登录.js
var users = {'dave' : 'expressrocks'};
module.exports = function (req, res, next) { var method = req.method.toLowerCase(), //cache the method
user = req.body.user,
logout = (method === 'delete'),
login = (method === 'post' && user),
routes = req.app.routes.routes[method];
if (!routes) { next(); return; }
if (login || logout) {
routes.forEach(function (route) {
if (!(req.url.match(route.regexp))) {
console.log(req.url);
req.method = 'GET';
}
});
}
if (logout) {
delete req.session.user;
}
if (login) {
Object.keys(users).forEach(function (name) {
if (user.name === name && user.pwd === users[name]) {
req.session.user = {
name: user.name,
pwd: user.pwd
};
}
});
}
if (!req.session.user) { req.url = '/'; }
next();
};
登录.jade
if user
form(method='post')
input(name="_method", type="hidden", value="DELETE")
p Hello #{user.name}!
a(href='javascript:', onClick='forms[0].submit()') [logout]
else
p Please log in
form(method='post')
fieldset
legend Login
p
label(for="user[name]") Username:
input(name="user[name]")
p
label(for="user[pwd]") Password:
input(type="password", name="user[pwd]")
input(type="submit")
来自终端的结果日志
错误来自以下行： routes = req.app.routes.routes[method]; 在login.js中
TypeError: Cannot read property 'get' of undefined
at Object.module.exports [as handle] (/home/chiasyan/Desktop/login/login.js:8:35)
at next (/home/chiasyan/Desktop/login/node_modules/express/node_modules/connect/lib/proto.js:199:15)
at store.get.next (/home/chiasyan/Desktop/login/node_modules/express/node_modules/connect/lib/middleware/session.js:309:9)
at /home/chiasyan/Desktop/login/node_modules/express/node_modules/connect/lib/middleware/session.js:333:9
at /home/chiasyan/Desktop/login/node_modules/express/node_modules/connect/lib/middleware/session/memory.js:50:9
at process.startup.processNextTick.process._tickCallback (node.js:244:9)
更新：
我改变了routes = req.app.routes .routes [method]; 但仍然有一个小错误。
在login.jade中找不到用户变量（用户在login.js中定义一次）
ReferenceError: /home/chiasyan/Desktop/login/views/login.jade:1
> 1| if user
2| form(method='post')
3| input(name="_method", type="hidden", value="DELETE")
4| p Hello #{user.name}!
user is not defined
引自 Node Cookbook
在 routes/index.js 中，我们现在可以简单地拥有以下代码：
index.js
exports.index = function (req, res) {
res.render('index', {title: 'Express'});
};
来自 Node Cookbook 的另一句话
由于我们不再使用路由，我们没有机会通过 req.session。用户通过 res.render。但是，我们可以使用动态助手来代替。动态助手可以访问 req 和 res 对象，它们在视图呈现之前被调用。我们传递给动态帮助对象的任何属性都作为局部变量推送到 Jade 视图。
由于我不能再在 Express 3.* 中使用动态助手，所以在app.js中我已更改为：
app.configure(function(){
app.use(function(req, res, next){
res.locals.user = req.session.user;
next();
});
});