Prax¶ ↑

A pure Ruby alternative to Pow!!

Aka a Rack application spawner and proxy for simpler local development. Calling myapp.dev and subdomain.myapp.dev with no configuration is simpler than editing your hosts file, starting your applications manually on port 3000, etc.

Why?¶ ↑

My GNU/Linux fork of Pow just broke on me badly, and I couldn’t read, less write the coffeescript it’s written in. I thus decided to try writing an alternative in Ruby. Good for me, because I now have a viable alternative, and learned a lot about TCP and UNIX sockets, the HTTP protocol, Rack and Ruby Threads.

Also, Prax only requires Ruby and the Rack gem, both you should have already installed if you are a Ruby Web developer.

Rubies¶ ↑

Prax has been developed with MRI Ruby 1.9.3 and newer, but should be compatible with most Ruby engines like Rubinius 2+ and JRuby 1.7+ in 1.9 modes. Ruby 1.8 is deprecated, and no longer supported.

Installing on GNU/Linux¶ ↑

First clone the repository somewhere (like /opt or /usr/local/lib), and run the installer which will install the port forwarding script and NSSwitch extension:

$ git clone git://github.com/ysbaddaden/prax.git /opt/prax
$ cd /opt/prax/ && ./bin/prax install

Now link your applications:

$ cd ~/Work/myapp
$ prax link

Point your browser to http://myapp.dev/ and wait for your Rack application to spawn.

To install Prax manually, or to review the installation process, please look at the prax-install script.

Ruby Version Managers¶ ↑

Prax being written in Ruby, version managers usually have problems to select the correct version of Ruby or gemset (for RVM) to run Prax and to run your Rack applications. You must configure Prax to handle your version manager correctly.

Start Prax automatically¶ ↑

You may want to create a prax.desktop file in ~/.config/autostart so that Prax will be started automatically when GNOME starts for example. Please see with your desktop environment which solution works best.

If you don’t use X, you may add a prax start line to your ~/.bashrc for example, but be aware that it will restart Prax (and all Rack instances) everytime you log in. That could be fixed with a --no-restart flag and a status command (contributions welcome).

Slowness¶ ↑

If you experience some regular slowness, where Prax seems to hang for periods of 5 seconds, this is because of the DNS resolution: NSSwitch tries a real DNS resolution before checking the prax extension. This usually creates an overhead of less than half a second, but sometimes takes 5 seconds on my Ubuntu 12.04.

You may try to move the prax NSSwitch extension before the dns one, so it looks like this:

hosts: files mdns4_minimal [NOTFOUND=return] prax dns mdns4

This will dramatically speed up the DNS resolution of *.dev domains, and it should never hang anymore, BUT please be aware that it may cause problems in regular DNS resolutions (it works correctly for me).

Mac OS X¶ ↑

Mac OS X isn’t supported yet. Feel free to contribute!

Features¶ ↑

This is an ever going work in progress, thought Prax isn’t missing much things to be on par with Pow! The current features have been implemented:

• HTTP Server

• HTTP Proxy

• HTTP Port Forwarding

• SSL support (if certs and keys are generated)

• Rack Handler (Racker)

• Rack Application spawn, restart, always restart and autokill

• Export ENV vars from a myapp/.env file

• Source ~/.praxconfig and myapp/.praxrc bash scripts

• xip.io support

• GNU/Linux:

  • NSSwitch DNS resolver (resolves *.dev domains to 127.0.0.1)

  • firewall rule (redirects root ports 80/443 to user ports 20559/20558)

  • install script

TODO¶ ↑

• Documentation

• Mac OS X:

  • firewall rule

  • DNS resolver

  • install script

• Commands for the prax script:

  • prax always_restart

  • prax status

  • prax start –no-restart

Credits¶ ↑

• Julien Portalier <[email protected]>

• Sam Stephenson, Nick Quaranto, 37signals for the sub command and Pow!

• pyromaniac for the initial NSSwitch extension