koa-router

Router middleware for koa. Provides RESTful resource routing.

koa-router

Router middleware for koa

  • Express-style routing using app.get, app.put, app.post, etc.
  • Named URL parameters and regexp captures.
  • String or regular expression route matching.
  • Named routes with URL generation.
  • Responds to OPTIONS requests with allowed methods.
  • Support for 405 Method Not Allowed and 501 Not Implemented.
  • Multiple route middleware.
  • Multiple routers.

Install using npm:

npm install koa-router

Kind: Exported class

Create a new router.

ParamTypeDescription
[app]koa.Applicationextend koa app with router methods
[opts]Object
[opts.prefix]Stringprefix router paths

Example
Basic usage:

var app = require('koa')();
var router = require('koa-router')();
 
router.get('/', function *(next) {...});
 
app
  .use(router.routes())
  .use(router.allowedMethods());

Or if you prefer to extend the app with router methods:

var app = require('koa')();
var router = require('koa-router');
 
app
  .use(router(app))
  .get('/', function *(next) {...});

Create router.verb() methods, where verb is one of the HTTP verbes such as router.get() or router.post().

Match URL patterns to callback functions or controller actions using router.verb(), where verb is one of the HTTP verbs such as router.get() or router.post().

router
  .get('/', function *(next) {
    this.body = 'Hello World!';
  })
  .post('/users', function *(next) {
    // ... 
  })
  .put('/users/:id', function *(next) {
    // ... 
  })
  .del('/users/:id', function *(next) {
    // ... 
  });

Route paths will be translated to regular expressions used to match requests.

Query strings will not be considered when matching requests.

Routes can optionally have names. This allows generation of URLs and easy renaming of URLs during development.

router.get('user', '/users/:id', function *(next) {
 // ... 
});
 
router.url('user', 3);
// => "/users/3" 

Multiple middleware may be given and are composed using koa-compose:

router.get(
  '/users/:id',
  function *(next) {
    this.user = yield User.findOne(this.params.id);
    yield next;
  },
  function *(next) {
    console.log(this.user);
    // => { id: 17, name: "Alex" } 
  }
);

Route paths can be prefixed at the router level:

var router = new Router({
  prefix: '/users'
});
 
router.get('/', ...); // responds to "/users" 
router.get('/:id', ...); // responds to "/users/:id" 

Named route parameters are captured and added to ctx.params.

router.get('/:category/:title', function *(next) {
  console.log(this.params);
  // => [ category: 'programming', title: 'how-to-node' ] 
});

Run middleware for named route parameters. Useful for auto-loading or validation.

router
  .param('user', function *(idnext) {
    this.user = users[id];
    if (!this.user) return this.status = 404;
    yield next;
  })
  .get('/users/:user', function *(next) {
    this.body = this.user;
  })

Control route matching exactly by specifying a regular expression instead of a path string when creating the route. For example, it might be useful to match date formats for a blog, such as /blog/2013-09-04:

router.get(/^\/blog\/\d{4}-\d{2}-\d{2}\/?$/i, function *(next) {
  // ... 
});

Capture groups from regular expression routes are added to ctx.captures, which is an array.

Kind: instance property of Router

ParamTypeDescription
pathString | RegExp
[middleware]functionroute middleware(s)
callbackfunctionroute callback

Returns router middleware which dispatches a route matching the request.

Kind: instance property of Router

Use given middleware(s) before route callback. Only runs if any route is matched.

Kind: instance method of Router

ParamType
middlewarefunction
[...]function

Example

router.use(session(), authorize());
 
// runs session and authorize middleware before routing 
app.use(router.routes());

Set the path prefix for a Router instance that was already initialized.

Kind: instance method of Router

ParamType
prefixString

Example

router.prefix('/things/:thing_id')

Returns separate middleware for responding to OPTIONS requests with an Allow header containing the allowed methods, as well as responding with 405 Method Not Allowed and 501 Not Implemented as appropriate.

router.allowedMethods() is automatically mounted if the router is created with app.use(router(app)). Create the router separately if you do not want to use .allowedMethods(), or if you are using multiple routers.

Kind: instance method of Router

ParamTypeDescription
[options]Object
[options.throw]Booleanthrow error instead of setting status and header

Example

var app = koa();
var router = router();
 
app.use(router.routes());
app.use(router.allowedMethods());

Register route with all methods.

Kind: instance method of Router

ParamTypeDescription
nameStringOptional.
pathString | RegExp
[middleware]functionYou may also pass multiple middleware.
callbackfunction

Redirect source to destination URL with optional 30x status code.

Both source and destination can be route names.

router.redirect('/login', 'sign-in');

This is equivalent to:

router.all('/login', function *() {
  this.redirect('/sign-in');
  this.status = 301;
});

Kind: instance method of Router

ParamTypeDescription
sourceStringURL, RegExp, or route name.
destinationStringURL or route name.
codeNumberHTTP status code (default: 301).

Create and register a route.

Kind: instance method of Router

ParamTypeDescription
nameStringOptional.
pathString | RegExpPath string or regular expression.
methodsArray.<String>Array of HTTP verbs.
middlewarefunctionMultiple middleware also accepted.

Lookup route with given name.

Kind: instance method of Router

ParamType
nameString

Generate URL for route. Takes either map of named params or series of arguments (for regular expression routes).

router.get('user', '/users/:id', function *(next) {
 // ... 
});
 
router.url('user', 3);
// => "/users/3" 
 
router.url('user', { id: 3 });
// => "/users/3" 

Kind: instance method of Router

ParamTypeDescription
nameStringroute name
paramsObjecturl parameters

Run middleware for named route parameters. Useful for auto-loading or validation.

Kind: instance method of Router

ParamType
paramString
middlewarefunction

Example

router
  .param('user', function *(idnext) {
    this.user = users[id];
    if (!this.user) return this.status = 404;
    yield next;
  })
  .get('/users/:user', function *(next) {
    this.body = this.user;
  })

Generate URL from url pattern and given params.

Kind: static method of Router

ParamTypeDescription
pathStringurl pattern
paramsObjecturl parameters

Example

var url = Router.url('/users/:id', {id: 1});
// => "/users/1" 

Please submit all issues and pull requests to the alexmingoia/koa-router repository!

Run tests using npm test.

If you have any problem or suggestion please open an issue here.