2 KiB
Expressive middleware for node.js using generators via co to make writing web applications and REST APIs more enjoyable to write.
Koa provides a useful set of methods that make day to day web application and API design much faster, and less error-prone than "raw" nodejs. Many of these utilities were extracted from Express, however moving them to this layer allows middleware developers to avoid boilerplate and refrain from re-implementing many of these features, sometimes incorrectly or incomplete.
Only methods that are common to nearly all HTTP servers are integrated directly into Koa's small ~400 SLOC codebase. No middleware are bundled with koa. If you prefer to only define a single dependency for common middleware, much like Connect, you may use koa-common.
Installation
$ npm install koa
To use Koa you must be running node 0.11.4 or higher for generator support, and must run node(1)
with the --harmony-generators flag. If you don't like typing this, add an alias to your shell profile:
alias node='node --harmony-generators'
Community
- API documentation
- Middleware list
- Wiki
- G+ Community
- Mailing list
- #koajs on freenode
Example
var koa = require('koa');
var app = koa();
// logger
app.use(function(next){
return function *(){
var start = new Date;
yield next;
var ms = new Date - start;
console.log('%s %s - %s', this.method, this.url, ms);
}
});
// response
app.use(function(next){
return function *(){
yield next;
this.body = 'Hello World';
}
});
app.listen(3000);
Running tests
$ make test
License
MIT