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cache-must-revalidate.js
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cache-must-revalidate.js
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const path = require("path");
const fs = require("fs");
const crypto = require("crypto");
const Koa = require("koa");
const PassThrough = require("stream").PassThrough;
const log = console.log;
const app = new Koa();
// 获取访问文件路径
app.use(async (ctx, next) => {
log("\n\n\n\n\n\n", "------------请求处理开始------------");
let reqPath = ctx.path;
log("request path", reqPath);
if (reqPath === "/") reqPath = "/index.html";
ctx.filePath = "resource" + reqPath;
next();
});
// 如果文件不存在则报错
app.use(async (ctx, next) => {
const filePath = ctx.filePath;
if (!fs.existsSync(filePath)) {
ctx.status = 404;
ctx.set({ "Content-Type": "text/html" });
ctx.body = "<h1>404 Not Found</h1>";
return;
}
next();
});
// 设置 MIME type
app.use(async (ctx, next) => {
const EXT_MIME_TYPES = {
default: "text/html",
".js": "text/javascript",
".css": "text/css",
".json": "text/json",
".jpeg": "image/jpeg",
".jpg": "image/jpg",
".png": "image/png"
};
const filePath = ctx.filePath;
const mimeType =
EXT_MIME_TYPES[path.extname(filePath)] || EXT_MIME_TYPES["default"];
log("mime_type", mimeType);
ctx.set("Content-Type", mimeType);
next();
});
// 设置缓存
app.use(async (ctx, next) => {
// 在此处设置缓存策略
ctx.set("Cache-Control", "max-age=86400,must-revalidate");
next();
});
// 返回文件内容
app.use(async (ctx, next) => {
const filePath = ctx.filePath;
const resStream = fs.createReadStream(filePath);
ctx.status = 200;
ctx.body = resStream.pipe(PassThrough());
log("------------请求处理完毕------------");
});
// 错误处理
app.on("error", err => {
console.log("server error", err);
});
app.listen(1030);