About

Kellner is a framework to scale high-frequency API-type HTTP traffic, using a new methodology for PHP network programming, centered around a libevent php extension.

Motivation

Web traffic has gone a long way from simply serving HTML pages and image files and is now much more often a transport layer for remote procedure calls (AJAX, REST, SOAP,...). This not just for public web services, but also often used as a communication method between the layers of a multi-tiered enterprise architecture.

We have found that current web application/server solutions are sometimes quite inadequate for handling this kind of traffic under high loads, and usually a broad set of optimizations and workarounds are required to gain scalability (in-memory caching, op-code caches, etc).

Proposal

How about skipping things like "installing the latest web server" or "let's implement memcached" or "have you tried an op-code cache" and writing a super scalable api server in PHP with very few lines of code? (no web server required)

Examples

Check out the code for the libevent php extension. Examples are found in the demo directory.

demos
|-- library  <-some patched ZF classes (the ZF version is outdated)
|-- misc  <-basic network programming examples to play with the extension
|   |-- bufferbot.php
|   |-- bufferevent.php
|   |-- chatserver.php
|   |-- httpclient.php
|   |-- httpdtest.php
|   `-- simple_client.php
|-- zf      <-Zend Framework MVC app demo
`-- zf-apiserver  <- Zend Framework Api demo server (JSON-RPC and XML-RPC)

ZF App Demo

This is a highly experimental sample poll application. It uses evhttp as an integrated webserver, serving a persistent Zend Framework MVC application. Performance and scalability is pretty interesting, but security concerns might result in heart attacks. So play with it, but don't use this anywhere in a production environment. (It's also work in progress)

To start: Make sure you have your Zend Framework copy linked correctly as /library/Zend.

> cd demos/zf/bin
> php main.php

To test: Point your web browser to: http://127.0.0.1:8080/ Note that the app is not meaningful yet. Feel free to play and extend it.
ZF API Server Demo

A more stable and useful example can be found in demos/zf-apiserver. It exports a basic poll service class as JSON-RPC and XML-RPC. Soap could be added pretty easily.

We found that without the front controller Zend Framework components work amazingly well with long running PHP processes. Have fun playing and load testing.

To start: Make sure you have your Zend Framework copy linked correctly as /library/Zend.

> cd demos/zf-apiserver/bin
> php main.php

To test, in a new shell type:

> cd demo/zf-apiserver/bin
> php test.php

Contribute

The current state of the project presents an interesting, new way of building php applications. If you're as excited about this the same way that we are, please check out a copy of the code and start playing with it. Feedback and contributions are more than welcome!

Best,

Florian