115 lines
3 KiB
Markdown
115 lines
3 KiB
Markdown
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[](https://travis-ci.org/koajs/koa)
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Expressive middleware for node.js using generators via [co](https://github.com/visionmedia/co)
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to make web applications and APIs more enjoyable to write. Koa's middleware flow in a stack-like manner allowing you to perform actions downstream, then filter and manipulate the response upstream. Koa's use of generators also greatly increases the readability and robustness of your application.
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Only methods that are common to nearly all HTTP servers are integrated directly into Koa's small ~400 SLOC codebase. This
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includes things like content-negotiation, normalization of node inconsistencies, redirection, and a few others.
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No middleware are bundled with koa. If you prefer to only define a single dependency for common middleware, much like Connect, you may use
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[koa-common](https://github.com/koajs/common).
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## Installation
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```
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$ npm install koa
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```
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To use Koa you must be running __node 0.11.9__ or higher for generator support, and must run node(1)
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with the `--harmony` flag. If you don't like typing this, add an alias to your shell profile:
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```
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alias node='node --harmony'
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```
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Another option, if you would like to use koa with __node 0.10.x__ (the current
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stable branch), or are tired of typing the `--harmony` flag, is to use
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[`gnode`](https://github.com/TooTallNate/gnode) to spawn your node instance.
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## Community
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- [API](docs/api/index.md) documentation
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- [Examples](https://github.com/koajs/examples)
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- [Middleware](https://github.com/koajs/koa/wiki) list
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- [Wiki](https://github.com/koajs/koa/wiki)
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- [G+ Community](https://plus.google.com/communities/101845768320796750641)
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- [Mailing list](https://groups.google.com/forum/#!forum/koajs)
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- [Guide](docs/guide.md)
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- [FAQ](docs/faq.md)
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- __#koajs__ on freenode
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## Example
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```js
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var koa = require('koa');
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var app = koa();
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// logger
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app.use(function *(next){
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var start = new Date;
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yield next;
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var ms = new Date - start;
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console.log('%s %s - %s', this.method, this.url, ms);
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});
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// response
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app.use(function *(){
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this.body = 'Hello World';
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});
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app.listen(3000);
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```
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## Running tests
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```
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$ make test
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```
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## Benchmarks
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If you like silly benchmarks, here's the requests per second using
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[wrk](https://github.com/wg/wrk) 3.x on my MBP.
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```
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1 middleware
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8367.03
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5 middleware
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8074.10
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10 middleware
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7526.55
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15 middleware
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7399.92
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20 middleware
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7055.33
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30 middleware
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6460.17
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50 middleware
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5671.98
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100 middleware
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4349.37
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```
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With __50__ middleware (likely much more than you'll need), that's __340,260__ requests per minute, and __20,415,600__ per hour, and over __440 million__ per day, so unless you're a Facebook and can't manage to spin up more
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than one process to scale horizontally you'll be fine ;)
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## Authors
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- [TJ Holowaychuk](https://github.com/visionmedia)
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- [Jonathan Ong](https://github.com/jonathanong)
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- [Julian Gruber](https://github.com/juliangruber)
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# License
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MIT
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