koa-bodyparser解析通过post提交的参数

给ctx.request.body赋值，数据是通过Buffer格式传递，用toString()转为字符串。返回给前台

  1. // 中间件：是一个函数，返回的是promise对象
  2. function bodyparser() {
  3.   return async (ctx, next) => {
  4.     await new Promise((resolve, reject) => {
  5.       let arr = [];
  6.       ctx.req.on("data", function (data) {
  7.         arr.push(data);
  8.       });
  9.       ctx.req.on("end", () => {
  10.         let res = Buffer.concat(arr).toString();
  11.         ctx.request.body = res;
  12.         resolve();
  13.       });
  14.     });
  15.     await next();
  16.   };
  17. }
  18. module.exports = bodyparser;

在end中处理不同的文件类型，主要处理上传文件类型。如果是数据直接返回，上传的是文件类型将文件写入到upload文件夹中。

  1.       ctx.req.on("end", () => {
  2.         let type = ctx.get("Content-Type");
  3.         // console.log(type);
  4.         if (type.includes("multipart/form-data")) {
  5.           let boundary = "--" + type.split("=")[1];
  6.           //   console.log(boundary);
  7.           let buffer = Buffer.concat(arr);
  8.           let lines = buffer.split(boundary).slice(1, -1);
  9.           let obj = Object.create(null);
  10.           lines.forEach((line) => {
  11.             console.log(line.toString());
  12.             let [head, content] = line.split("\r\n\r\n");
  13.             head = head.toString();
  14.             let key = head.match(/name="(.+?)"/)[1];
  15.             // console.log(head);
  16.             // 解析不同类型，文件以及数据
  17.             if (head.includes("filename")) {
  18.               // 上传的是文件类型
  19.               let filename = uuid.v4();
  20.               fs.writeFileSync(
  21.                 path.resolve(__dirname, "upload", filename),
  22.                 content.slice(0, -2),
  23.                 "utf8"
  24.               );
  25.               obj[key] = filename;
  26.             } else {
  27.               // 正常数据流
  28.               obj[key] = content.slice(0, -2).toString();
  29.             }
  30.           });
  31.           ctx.request.body = obj;
  32.           resolve();
  33.         } else {
  34.           resolve();
  35.         }
  36.       });

处理静态文件路径koa-static

在页面中引入的文件路径，解析成静态资源。可以直接在前端页面进行显示

  1. const { createReadStream } = require("fs");
  2. const fs = require("fs").promises;
  3. const path = require("path");
  4. const mime = require("mime");
  5. function static(dirname) {
  6.   return async (ctx, next) => {
  7.     try {
  8.       let filePath = path.join(dirname, ctx.path);
  9.       let statObj = await fs.stat(filePath);
  10.       if (statObj.isDirectory()) {
  11.         filePath = path.join(filePath, "index.html");
  12.         await fs.access(filePath);
  13.       }
  14.       ctx.set("Content-Type", mime.getType(filePath) + ";charset=UTF-8");
  15.       ctx.body = createReadStream(filePath);
  16.     } catch (e) {
  17.       console.log(e);
  18.       await next();
  19.     }
  20.   };
  21. }