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ctx.request.length

The `Content-Length` of the request body in bytes, parsed as an integer.

Since Koa 2 Spec ↗

Syntax

ctx.request.length

Returns

number | undefined — Content-Length in bytes, or `undefined` if the header is absent.

Examples

import Koa from 'koa';

const app = new Koa();

const MAX_BODY = 1_000_000; // 1 MB

app.use(async (ctx, next) => {
  if (ctx.request.length && ctx.request.length > MAX_BODY) {
    ctx.throw(413, 'Payload Too Large');
  }
  await next();
});

app.use(async (ctx) => {
  ctx.body = 'ok';
});

app.listen(3000);
Output 
POST with 2 MB body → 413 Payload Too Large

Notes

Returns `undefined` when the `Content-Length` header is absent (e.g. chunked transfer encoding). For reliable body size limiting, also configure the limit option in `koa-bodyparser` which handles chunked requests.

See also