title: koa2 post always show Method Not Allowed？
body: <pre><code>//server.js
  const Koa = require('koa')
  const app = new Koa();
  const bodyParser = require('koa-bodyparser');
  app.use(bodyParser());   
  const Router = require('koa-router');
  const fs = require('fs');
  
  const router = new Router();
  const UserController = require('./server/controller/user.js');
  const checkToken = require('./server/token/checkToken.js');
  router.get('/user/login', async ctx =&gt; {
   ctx.body = JSON.parse(fs.readFileSync( './pass.json'));
   console.log(ctx.body);
   });
  
  router.post('/signin', async (ctx, next) =&gt; {
    var
      name = ctx.request.body.name || '',
      password = ctx.request.body.password || '';
      console.log(`signin with name: ${name}, password: ${password}`);
    if (name === 'koa' &amp;&amp; password === '12345') {
   ctx.response.body = `&lt;h1&gt;Welcome, ${name}!&lt;/h1&gt;`;
    } else {
   ctx.response.body = `&lt;h1&gt;Login failed!&lt;/h1&gt;
   &lt;p&gt;&lt;a href="/"&gt;Try again&lt;/a&gt;&lt;/p&gt;`;
   }
   });
  
       app.use(router.routes()).use(router.allowedMethods());
  
  app.listen(8090, () =&gt; {
     console.log('The server is running at http://localhost:' + 8090);
   });
  </code></pre>
  
  <hr>
  
  <pre><code>koa:2.52
  koa-bodyparse:4.21
  koa-router:7.4
  </code></pre>
  
  <p>when I type <a href="http://localhost:8090/user/login" rel="nofollow noreferrer">http://localhost:8090/user/login</a> can get the Json data,but type <a href="http://localhost:8090/signin" rel="nofollow noreferrer">http://localhost:8090/signin</a> always show 405  Methods Not Allowed ,(debian firefxo) show Request Method "GET",response Allow: POST,Connection: "keep-alive" 
  I hope get your help.</p>