新尝试另一个语言node.js和框架express，记录一些基本的操作与技巧。
此次最大的不同是node.js是异步的，有些操作就不那么直观。
这里在linux centos做测试。前提先安装好node.js和npm。
这里也类似上次flask完成一个登陆与增删改操作的接口。
先用命令行直接生成一个项目
npm install express-generator -g express --view=pug myappcd myapp && npm install npm start
app.js主文件
//最后两个为session所需库，还有mongodb库，需自行下载
//npm install --save express-session,session-file-store,mongodb
var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var session = require('express-session');
var FileStore = require('session-file-store')(session);
#引入路由文件
var RetInfo = require("./common/retinfo");
var index = require('./routes/index');
var users = require('./routes/users');
var manage = require('./routes/manage');
var app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
//解析请求body
// 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')));
//开启并设置session
app.use(session({
secret: 'chyingp',
store: new FileStore(),
saveUninitialized: false,
resave: false,
cookie: {
maxAge: 24*60*60*1000
}
}));
//绑定路由，中间件
app.use('/', index);
app.use('/users', users);
//不设置的则下面的路由都会运行这个函数
app.use(function(req,res,next) {
var sess = req.session;
var loginUser = sess.loginUser;
if(loginUser===undefined) return res.json(RetInfo.error("login out"));
next();
});
//绑定另一个中间件，需登录后
app.use('/manage',manage);
//错误处理
// 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;
根目录下 新建一个文件夹common/用于存放通用函数，下面写了两种形式。
common/retinfo.js 用于接口返回数据
module.exports = {
response : function(sts,msg) {
return {"sts":sts,"msg":msg}
},
success : function() {
return this.response(1,"success")
},
error : function(msg) {
return this.response(-1,msg)
},
dberr : function(msg) {
return this.response(-1,"db error");
}
}
common/mongodb.js 用于数据库操作,这里使用了promise，因为mongodb操作后会有回调函数，不方便调用，写成promise就可以用then进行下去。
//use for mongodb database
var MongoClient = require('mongodb').MongoClient;
function Mongodb(dbName, colName){
this.dbName = dbName;
this.colName = colName;
this.url = 'mongodb://localhost:27017/';
this.fetch = function(params){
//回调函数里没法获取到外部的this，所以再定义一下that
var that = this;
return new Promise(function(resolve, reject, notufy) {
MongoClient.connect(that.url, function(err, db){
if(err) reject(err);
var dbo = db.db(that.dbName);
dbo.collection(that.colName).find(params).toArray(function(err, res){
if(err) reject(err);
resolve(res);
db.close();
});
});
});
};
this.save = function(params){
var that = this;
return new Promise(function(resolve, reject, notufy){
MongoClient.connect(that.url, function(err, db){
if(err) reject(err);
var dbo = db.db(that.dbName);
dbo.collection(that.colName).insertOne(params, function(err, res){
if(err) reject(err);
resolve(res);
db.close();
});
});
});
};
this.delete = function(params){
var that = this;
return new Promise(function(resolve, reject, notufy){
MongoClient.connect(that.url, function(err, db){
if(err) reject(err);
var dbo = db.db(that.dbName);
dbo.collection(that.colName).deleteOne(params, function(err, res){
if(err) reject(err);
resolve(res);
db.close();
});
});
});
}
this.update = function(whparams,params){
var that = this;
return new Promise(function(resolve, reject, notufy){
MongoClient.connect(that.url, function(err, db){
if(err) reject(err);
var dbo = db.db(that.dbName);
dbo.collection(that.colName).updateOne(whparams, {$set:params}, function(err, res){
if(err) reject(err);
resolve(res);
db.close();
});
});
});
}
}
module.exports = Mongodb;
然后编写中间件routes/users.js
var express = require('express');
var router = express.Router();
var RetInfo = require("../common/retinfo");
//登录
router.get('/login', function(req, res, next) {
username = req.query.username;
password = req.query.password;
if(!username || !password) return res.json(RetInfo.error("lack of params"));
if(username == "admin" && password == "admin"){
req.session.regenerate(function(err) {
if(err) return res.json(RetInfo.error("login error"));
req.session.loginUser = username;
return res.json(RetInfo.success());
});
}else{
return res.json(RetInfo.error("username or password error"));
}
});
//登出
router.get("/loginout", function(req, res, next) {
req.session.destroy(function(err) {
if(err) return res.json(RetInfo.error("login out error"));
return res.json(RetInfo.success());
});
})
module.exports = router;
routes/manage.js 这里写了一般的增删改操作
var express = require('express');
var router = express.Router();
var RetInfo = require("../common/retinfo");
var Mongo = require("../common/mongodb");
DB_POSTS = new Mongo("test_database","posts");
//获取数据
router.get("/",function(req, res, next){
DB_POSTS.fetch({}).then((data)=>{
return res.send(data);
},(err)=>{
return res.send(RetInfo.error(err.message));
});
})
//增加
.post("/",function(req, res, next){
DB_POSTS.save(req.body).then((data)=>{
return res.send(RetInfo.success());
},(err)=>{
return res.send(RetInfo.error(err.message));
});
})
//删除
.delete("/",function(req, res, next){
data={"_id":req.query.id}
DB_POSTS.delete(data).then((data)=>{
return res.send(data)
},(err)=>{
return res.send(RetInfo.error(err.message))
});
})
//修改
.put("/",function(req, res, next){
const params = req.body;
DB_POSTS.update({"_id":params.id},params).then((data)=>{
return res.send(RetInfo.success());
},(err)=>{
return res.send(RetInfo.error(err.message));
})
})
module.exports = router;
运行的话可以有很多方法
一般运行 npm start debug模式 DEBUG=myapp:* npm start 开发修改后自动重启 nodemon app.js 后台一直运行 forever start ./bin/www
后言：对于js语法 es6等还比较生疏，并没有涉及，可能有待改进，但总怕麻烦。。。。
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CC BY-NC-SA 4.0协议。
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