# 一.计算机网络
- 1.防盗链
let http = require("http");
let url = require("url");
let path = require("path");
let fs = require("fs");
let util = require("util");
let stat = util.promisify(fs.stat);
let mime=require('mime')
let server = http.createServer(function(req, res) {
let { pathname } = url.parse(req.url);
//拼接真实文件路径
let realPath = path.join(__dirname, pathname);
try{
let statObj=await stat(realPath)
//是文件 返回文件
if(statObj.isFile()){
//类型库mime
res.setHeader('Content-Type',mime.getType(ealPaht)+';charset=utf8')
fs.createReadStream(realPath).pipe(res)
}else{
//目录找html
let url=path.join(realPath,'index/html')
res.setHeader('Content-Type','text/html;charset=utf8')
fs.createReadStream(url).pipe(res)
}
}catch(e){
res.statusCode=404
res.end('Not found')
}
// fs.stat(realPath, function(err, statObj) {
// if (err) {
// res.statusCode = 404;
// res.end("Not found");
// } else {
// if (statObj.isFile()) {
// res.setHeader("Content-Type", "text/html;charset=utf8");
// fs.createReadStream(realPath).pipe(res);
// } else {
// let url = path.join(realPath, "index.html");
// fs.createReadStream(realPath).pipe(res);
// }
// }
// });
});
server.listen(3000, function() {
console.log("3000");
});
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
hello 你好
</body>
</html>
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- 2.多语言
let http = require("http");
let url = require("url");
let path = require("path");
let fs = require("fs");
let obj = {
zh: {
data: "你好"
},
en: {
data: "hello"
},
ja: {
data: "1234"
}
};
let defaultLanguage = "en";
let server = http.createServer(async function(req, res) {
let lan = req.headers["accept-language"];
res.setHeader("Content-Type", "text/plain;charset=utf8");
if (lan) {
let lans = lan
.split(",")
.map(l => {
let [name, q = 1] = l.split(";");
return {
name,
q: q === 1 ? 1 : Number(q.split("=")[1])
};
})
.sort((a, b) => b.q - a.q);
for (let i = 0; i < lans.length; i++) {
let lanName = lans[i].name;
if (obj[lanName]) {
res.end(pobj[lanName].data);
}
}
console.log(lans);
} else {
res.setHeader("Content-Type", "text/plain;charset=utf8");
res.end(obj[defaultLanguage].data);
}
});
server.listen(3000, function() {
console.log(3000 + "连接成功");
});
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- 3.缓存
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
缓存
</body>
</html>
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//304走浏览器的缓存
//缓存的类型 有两种 强制缓存 + 对比缓存
let http = require("http");
//页面 可能内部引用一个css 我希望css缓存
let url = require("url"); // pathname,query
let path = require("path");
let fs = require("fs");
let util = require("util");
let stat = util.promisify(fs.stat);
let mime = require("mime");
let crypto = require("crypto");
let server = http.createServer(async function(req, res) {
console.log(req.url);
//告诉浏览器十秒内不要找我
res.setHeader("Cache-Control", "no-cache");
res.setHeader("Exipres", new Date(Date.now() + 10 * 1000).toLocaleString());
//第一次访问的时候， 要给浏览器加一个头last-modified
//第二次请求的时候，会自动带一个头 if-modify
//如果当前带过来的头和文件当前的状态有出入，说明文件
//第一次来访问 给你一个文件的签名 Etag ：各种
//下次你再来访问 会带上这个标签 if-none-match
//我在去拿文件当前的内容 在生成一个标签 如果相等 返回304
let { pathname } = url.parse(req.url);
let realPath = path.join(__dirname, pathname); // 拼接真实文件的路径
try {
let statObj = await stat(realPath); // 判断文件是否存在
if (statObj.isFile()) {
res.setHeader('Etag');
crypto.createHash('md5')
let prev = req.headers["if-modified-since"];
let current = statObj.citime.toGMTString();
if (prev === current) {
res.statusCode = 304;
res.end();
}
// 是文件 返回文件
res.setHeader("Content-Type", mime.getType(realPath) + ";charset=utf-8");
fs.createReadStream(realPath).pipe(res);
} else {
res.setHeader("Last-Modified", statObj.ctime.toGMTString());
let url = path.join(realPath, "index.html"); // 目录找html
res.setHeader("Content-Type", "text/html;charset=utf-8");
fs.createReadStream(url).pipe(res);
}
} catch (e) {
// 不存在返回404
res.statusCode = 404;
res.end("Not found");
}
});
server.listen(3000, function() {
console.log(`server start 3000`);
});
//第一次来先来个强制缓存Cache-Control + expires
//过了10s再刷新 此时会再次发送请求 启用对比缓存
// 1) Last-Modified:ctime 2)if-modified-since
//1) Etag 2)if-none-match
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//crypto 加密 md5(摘要算法)
//md5的特点 不可逆
//不同的内容加密长度是一样的
//如果内容不相同 那么摘要的结果肯定也是不同的
let crypto = require("crypto");
let r = crypto
.createHash("md5")
.update("123456")
.digest("base64");
console.log(r);
//加盐算法
//弄一个密码 根据我的密码进行加密 加密cookie
let fs = requier("fs");
let s = fs.readFileSync();
let r2 = crypto
.createHmac("sha1", s)
.update("123456")
.digest("hex");
console.log(r2);
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