title: Node.js
date: 2019-09-01 14:27:58
tags: 后端
categories: # 这里写的分类会自动汇集到 categories 页面上，分类可以多级
node.js
基础
简易版 node-server
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var http = require("http");
var server = http.createServer(function (request, response) {
response.setHeader("Content-Type", "text/plain; chartset=gbk");
response.writeHead(200, "ok");
response.write("hello");
response.end();
});
server.listen(9000);
console.log("open http://localhost:9000");
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在终端中输入node index.js就启动服务器.
简单版服务器
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| var http = require("http");
var fs = require("fs");
var server = http.createServer(function (req, res) {
console.log(__dirname + "/static" + req.url);
var fileContent = fs.readFileSync(__dirname + "/static" + req.url, "binary");
res.write(fileContent, "binary");
res.end();
});
server.listen(8080);
console.log("visit localhost:8080");
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进阶
静态服务器.
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| var http = require("http")
var path = require("path")
var fs = require("fs")
var url = require("url")
function staticRoot(staticPath, req, res){
var pathObj = url.parse(req.url, true)
console.log(pathObj)
if(pathObj.pathname === "/"){
pathObj.pathname += "index.html"
}
var filePath = path.join(staticPath, pathObj.pathname)
fs.readFile(filePath, "binary", function(err, fileContent){
if(err){
res.writeHead(404, "not found")
res.end("<h1>404 Not Found</h1>")
}else{
res.writeHead(200, "ok")
res.write(fileContent, "binary")
res.end()
}
})
console.log("path.join(_dirname, "static")
var server = http.createServer(function(res,req){
staticRoot(path.join(__dirname, "static"), req, res)
//__dirname代表当前文件路径,join拼接上static路径
})
server.listen(8080)
console.log("visit http:
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mock 数据
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var http = require("http");
var fs = require("fs");
var url = require("url");
http
.createServer(function (req, res) {
var pathObj = url.parse(req.url, true);
switch (pathObj.pathname) {
case "/getWeather":
res.end(JSON.stringify({ a: 1, b: 2 }));
break;
case "user/123":
res.end(fs.readFileSync(__dirname + "/static/user.tpl"));
break;
default:
res.end(fs.readFileSync(__dirname + "static" + req.url));
}
})
.listen(8080);
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问题
__dirname是什么
__dirname总是指向被执行文件的绝对路径.
如/d1/d2/my.js中的__dirname,他的值就是/d1/d2.
常用 API
fs.readFile(path[,options],callback)/fs.writeFile(file,data[,options],callback)
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| let fs = require("fs");
fs.readFile("flie.txt", "utf-8", function (err, str) {
if (err) {
console.log("error");
} else {
console.log(str);
const strAfter = str.replace(/\d/gm, "");
console.log(strAfter);
fs.writeFile("fileAfter.txt", strAfter, (err) => {
if (err) throw err;
console.log("the file has been save!");
});
}
});
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模块
将上面的去数字的方法封装成函数,单独写一个文件,并调用
创建stringApi.js
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| function replaceDigit(str) {
return str.replace(/\d/gm, "");
}
module.exports.replaceDigit = replaceDigit;
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let strApi = require("./stringApi");
const strAfter = strApi.replaceDigit(str);
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NPM
如果需要一些功能,node.js 自带的没有,可以去 npm 官网上找一些其他人发布的 npm 包.
找到之后,首先进行安装
package.json
记录保存模块依赖,当没有依赖时,比如下载其他人的项目里没有依赖,可以使用npm.init初始化,将 package.json 中记录的模块依赖全都下载下来,方便.
npm 切换源工具
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| npm install -g nrm
nrm ls
nrm use taobao
nrm use npm
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NPM Script
在 package.json 文件里有一个 scripts 对象,写入里面的命令可以比较方便快捷的执行.直接npm xxx就可以执行.而且会自动搜索路径,不用写相对路径.
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| {
"scripts": {
"css:autoprefixer": "postcss -u autoprefixer -r dist/css/*",
"css:compress": "csso in.css --output out.css",
"js:lint": "eslint src/js",
"js:uglify": "mkdir -p dist/js && uglifyjs src/js/*.js -m -o dist/js/app.js",
"image:imagemin": "app=imagemin-cli npm run check; imagemin src/images dist/images -p",
"server": "browser-sync start --server --files 'dist/css/*.css, dist/js/*.js'",
"watch": "onchange 'src/js/*.js' -- npm run css:compress",
"start": "npm run server"
}
}
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| npm run css:autoprefixer
npm start
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