【笔记】Koa学习笔记
6Jyc5p+a
·
2026-06-16
·
via 6Jyc5p+a
前言
Expressive HTTP middleware framework for node.js to make web applications and APIs more enjoyable to write.（Github）
下载依赖
引入依赖
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| const Koa = require("koa");
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创建Web服务器
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| const app = new Koa();
app.use(function (context, next) {
context.body = "";
});
app.listen(8080);
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| const app = new Koa();
app.use(function (context, next) {
context.body = "";
});
app.listen(8080, function () {
console.log(`http://127.0.0.1:8080`);
});
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| const app = new Koa();
app.use(function (context, next) {
context.body = "";
});
app.listen(8080, "0.0.0.0", function () {
console.log(`http://127.0.0.1:8080`);
});
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中间件
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| app.use(function (context, next) {
...
});
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继续下一个中间件
处理请求
获取Nodejs请求对象
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| const request = context.req;
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获取Koa请求对象
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| const request = context.request;
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获取请求行
获取请求URL
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| const path = context.request.path;
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| const path = context.path;
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获取请求方法
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| const method = context.request.method;
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| const method = context.method;
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处理响应
获取Nodejs响应对象
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| const response = context.res;
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获取Koa响应对象
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| const response = context.response;
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设置响应体并返回响应
路由
下载依赖
引入依赖
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| const KoaRouter = require("@koa/router");
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定义路由
- 如果没有注册
router.allowedMethods()，则访问没有匹配的路由时会返回Not Found
- 如果注册了
router.allowedMethods()，则访问没有匹配的路由时会返回Method Not Allowed
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| const router = new KoaRouter({ prefix: "/api" });
router.get("/", function (context, next) {
...
});
app.use(router.routes());
app.use(router.allowedMethods());
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处理请求
获取请求参数
query
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| router.get("/", function (context, next) {
const query = context.query;
});
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path
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| router.get("/:id", function (context, next) {
const id = context.params.id;
});
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下载依赖
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| npm install koa-bodyparser
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| const bodyParser = require("koa-bodyparser");
app.use(bodyParser());
app.use(function (context, next) {
const body = context.request.body;
});
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下载依赖
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| npm install @koa/multer multer
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| const multer = require("@koa/multer");
const formParser = multer();
app.use(formParser.any(), function (context, next) {
const body = context.request.body;
});
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解析单个文件上传请求参数
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| const multer = require("@koa/multer");
const upload = multer({ dest: "./uploads" });
app.use(upload.single("key"), function (context, next) {
const file = context.request.file;
});
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| const multer = require("@koa/multer");
const upload = multer({
storage: multer.diskStorage({
destination: function (request, file, callback) {
callback(null, "./uploads");
},
filename: function (request, file, callback) {
callback(null, file.originalname);
}
})
});
app.use(upload.single("key"), function (context, next) {
const file = context.request.file;
});
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解析多个文件上传请求参数
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| const multer = require("@koa/multer");
const upload = multer({ dest: "./uploads" });
app.post("/", upload.array("key"), function (context, next) {
const files = context.request.files;
});
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完成
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