koa-send

What is koa-send?

The koa-send package is a utility for Koa applications that allows you to serve static files. It is commonly used to serve files such as HTML, CSS, JavaScript, images, and other static assets from a directory on the server.

What are koa-send's main functionalities?

Serving Static Files

This feature allows you to serve static files from a specified path. In this example, when a request is made to '/static', the server responds with the file located at 'path/to/static/file.html'.

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

app.use(async (ctx) => {
  if (ctx.path === '/static') {
    await send(ctx, 'path/to/static/file.html');
  }
});

app.listen(3000);

Serving Files from a Directory

This feature allows you to serve files from a directory. In this example, any request path will be mapped to a file in the 'public' directory relative to the current directory.

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

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

app.listen(3000);

Setting Cache Control Headers

This feature allows you to set cache control headers for the served files. In this example, the 'maxage' option is set to 1 hour, which will set the 'Cache-Control' header to cache the file for 1 hour.

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

app.use(async (ctx) => {
  await send(ctx, 'path/to/static/file.html', { maxage: 1000 * 60 * 60 }); // 1 hour
});

app.listen(3000);

Other packages similar to koa-send

koa-static

koa-static is another middleware for serving static files in a Koa application. It is similar to koa-send but is more focused on serving static files from a directory. It provides a simpler API for serving static files and is often used in conjunction with other Koa middlewares.

serve-static

serve-static is a middleware for serving static files in Express applications, but it can also be used with Koa through the koa-connect package. It provides similar functionality to koa-send, allowing you to serve static files from a directory with options for caching and other settings.

koa-static-cache

koa-static-cache is a Koa middleware for serving static files with caching capabilities. It is similar to koa-send but includes built-in support for caching files in memory, which can improve performance for frequently accessed files.

README

koa-send

Static file serving middleware.

Installation

$ npm install koa-send

Options

• maxage Browser cache max-age in milliseconds. defaults to 0
• hidden Allow transfer of hidden files. defaults to false
• root Root directory to restrict file access
• 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.
• 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/

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(function *(){
  yield send(this, this.path, { root: __dirname + '/public' });
})

To serve developer specified files:

app.use(function *(){
  yield send(this, 'path/to/my.js');
})

Example (Koa@2) with async/await

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

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

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

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

Example

var send = require('koa-send');
var koa = require('koa');
var app = koa();

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

app.use(function *(){
  if ('/' == this.path) return this.body = 'Try GET /package.json';
  yield send(this, this.path);
})

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

License

MIT