Transfer static files

Usage no npm install needed!

<script type="module">
  import shellscapeKoaSend from 'https://cdn.skypack.dev/@shellscape/koa-send';



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Static file serving middleware.


$ npm install koa-send


  • maxage Browser cache max-age in milliseconds. (defaults to 0)
  • immutable Tell the browser the resource is immutable and can be cached indefinitely. (defaults to false)
  • hidden Allow transfer of hidden files. (defaults to false)
  • root Root directory to restrict file access.
  • index Name of the index file to serve automatically when visiting the root location. (defaults to none)
  • gzip Try to serve the gzipped version of a file automatically when gzip is supported by a client and if the requested file with .gz extension exists. (defaults to true).
  • brotli Try to serve the brotli version of a file automatically when brotli is supported by a client and if the requested file with .br extension exists. (defaults to true).
  • format If not false (defaults to true), format the path to serve static file servers and not require a trailing slash for directories, so that you can do both /directory and /directory/.
  • setHeaders Function to set custom headers on response.
  • extensions Try to match extensions from passed array to search for file when no extension is sufficed in URL. First found is served. (defaults to false)

Root path

Note that root is required, defaults to '' and will be resolved, removing the leading / to make the path relative and this path must not contain "..", protecting developers from concatenating user input. If you plan on serving files based on user input supply a root directory from which to serve from.

For example to serve files from ./public:

app.use(async (ctx) => {
  await send(ctx, ctx.path, { root: __dirname + '/public' });

To serve developer specified files:

app.use(async (ctx) => {
  await send(ctx, 'path/to/my.js');


The function is called as fn(res, path, stats), where the arguments are:

  • res: the response object
  • path: the resolved file path that is being sent
  • stats: the stats object of the file that is being sent.

You should only use the setHeaders option when you wish to edit the Cache-Control or Last-Modified headers, because doing it before is useless (it's overwritten by send), and doing it after is too late because the headers are already sent.

If you want to edit any other header, simply set them before calling send.


const send = require('koa-send');
const Koa = require('koa');
const app = new Koa();

// $ GET /package.json
// $ GET /

app.use(async (ctx) => {
  if ('/' == ctx.path) return ctx.body = 'Try GET /package.json';
  await send(ctx, ctx.path);

console.log('listening on port 3000');