最近看完了《Node.js开发指南》一书,有两个比较惭愧的地方:1)这本书是一名清华大学大二的学生写的。2)我看的是电子书。。。这本书总体来说,还是不错的,一看就懂,绝对能帮你入门。知识点覆盖蛮全的。当然这不是一本“揭秘“类丛书,所以没有很深入的研究。当然,node.js也不需要深入,谁都不知道他能活多久。
当开始尝试实践里面的例子的时候,遇到了不小的麻烦,首先是express库已经从2.0升级到了3.0,很多api不能用了,很多组件也被独立出来了,在网上找了很久才找到替换方案。
同时,因为书里面没有讲解app.use()和app.set()是干什么用的,这个让我很不解。直到我上网看到了几篇express.js代码研究的博客,豁然开朗。app.use()就是往express.js/或者connect.js内部的stack里面放东西,比如用户请求网址"/xxx",按照入栈的顺序(所以那个应该是队列吧),express会挨个调用stack里面的函数(也可能是stack里面对象的函数)。有favicon的,有static路由的,有rounter的)。
现在也理解了网友给出的app.DynamicHelpers()废弃掉之后的解决方案:
app.use(function(req,res,next){
res.locals.user = req.session ? req.session.user:'';
res.locals.keyword = req.session ? req.session.keyword:'';
next();
});
加入一个路由,使得每个web请求时,都会在res.locals里面加入2个属性:user,keyword。当然这个use一定要在app.use(session)之后,app.use(router)之前调用。
好了,经过2周左右的学习,基本上node.js算入门了,入门对我来说也已经够了~~~接下来再玩些别的。下面贴一下我的部分代码(兼容express.js 3)
app.js:
/**
* Module dependencies.
*/
var express = require('express')
, partials = require('express-partials')
// , mongoUtil = require('./mongoUtil.js')
, MongoStore = require('connect-mongo')(express)
, settings = require('./settings.js')
, routes = require('./routes')
, 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', 'ejs');
app.use(partials());
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(express.cookieParser());
app.use(express.session({
secret: settings.cookieSecret,
store: new MongoStore({db: settings.db})
}));
app.use(function(req,res,next){
res.locals.user = req.session ? req.session.user:'';
res.locals.keyword = req.session ? req.session.keyword:'';
next();
});
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));
});
app.configure('development', function(){
app.use(express.errorHandler());
});
routes(app);
http.createServer(app).listen(app.get('port'), function(){
console.log("Express server listening on port " + app.get('port'));
});
index.js:
var User = require("../user")
module.exports = function(app) {
app.get('/', function(req, res) {
res.render('index', {title: '首页'});
});
app.get('/reg', function(req, res) {
res.render('reg', {title: '用户注册'});
});
app.post('/reg', function(req, res){
// insert to mongo db
var user = new User(req.body["username"], req.body["password"]);
user.add();
res.render("/", {title: "恭喜注册成功"})
});
app.get('/login', function(req, res){
res.render("login", {title: "Login please..."})
});
app.post('/login', function(req, res){
// insert to mongo db
var user = new User(req.body["username"], req.body["password"]);
user.exists(function(exists){
if(exists) {
req.session.user = user;
res.redirect("/");
}
else {
req.session.user = null;
res.redirect("/login");
}
});
});
app.get('/login', function(req, res){
res.render('reg', {title: 'haha'});
});
};
user.js:
var MongoClient = require('mongodb').MongoClient;
var mongoUtil = require('./mongoUtil')
module.exports = User;
function User(name, psw){
this.name = name;
this.psw = psw;
}
User.prototype.users = [];
User.prototype.add = function add()
{
var that = this;
//User.prototype.users.push(this);
// insert a record to mongo db
MongoClient.connect(mongoUtil.getDbUrl(), function(err, db) {
if(err) { return console.dir(err); }
db.collection('users', function(err, items) {
items.findOne({"name" : that.name}, function(err, item){
if (!item)
items.insert({"name": that.name, "psw":that.psw}, {w:1}, function(err, result){});
});
});
});
}
User.prototype.remove = function remove()
{
// remove current user
}
User.prototype.exists = function exists(callback)
{
var that = this;
MongoClient.connect(mongoUtil.getDbUrl(), function(err, db) {
if(err) { return false; }
db.collection('users', function(err, items) {
items.findOne({"name" : that.name}, function(err, item){
if (item)
callback(true);
else
callback(false);
});
});
});
}
mongoUtil.js:
exports.getDbUrl = function(){
if(process.env.VCAP_SERVICES){
var env = JSON.parse(process.env.VCAP_SERVICES);
var mongo = env['mongodb-2.0'][0]['credentials'];
}
else{
var mongo = {
"hostname":"localhost",
"port":27017,
"username":"",
"password":"",
"name":"",
"db":"db"
}
}
var generate_mongo_url = function(obj){
obj.hostname = (obj.hostname || 'localhost');
obj.port = (obj.port || 27017);
obj.db = (obj.db || 'test');
if(obj.username && obj.password){
return "mongodb://" + obj.username + ":" + obj.password + "@" + obj.hostname + ":" + obj.port + "/" + obj.db;
}
else{
return "mongodb://" + obj.hostname + ":" + obj.port + "/" + obj.db;
}
}
return generate_mongo_url(mongo);
};