Ruby « Top Secret Project

PHP equivalent of Django Admin?

Wednesday, August 20th, 2008

So … where is the PHP equivalent of Django Admin? Or the multitude of Rails Admin plugins?

I don’t care what framework it sits on as long as the out-of-the-box functionality is awesome.

Posted in PHP, Programming, Ruby, Ruby on Rails, Technology | 2 Comments »

Rails Plugin - Acts As Scheduled

Saturday, April 19th, 2008

I’ve just released the first pass of a Ruby on Rails Plugin called Acts As Scheduled.

acts_as_scheduled allows you to manage scheduled events for your models.

A good example of this is scheduling the update of RSS Feeds in a background process using Cron or BackgroundRB.

With acts_as_scheduled your schedule manager can simply call “Model.find_next_scheduled()” to grab the next item from the database.

At the moment it assumes you are working with MySQL.

All you need to get started is to add two extra columns to your table:

t.integer frequency
t.datetime last_scheduled

frequency is the number of seconds for your schedule.
last_scheduled is the date and time the record was last processed.

Ruby on Rails is real smart with times, so you don’t have to worry too much about calculating frequency values:

model.frequency = 1.day
model.frequency = 1.minute
model.frequency = 10.second

In your model class your simply declare “acts_as_scheduled” and you now have two extra methods find_next_scheduled and schedule_complete.

find_next_scheduled
Returns the next scheduled record from the table.
The next scheduled record is calculated as “the record who’s last_scheduled value is less than the current time minus the specified frequency in seconds”.

Which is the complex way of saying “if freqency is 1 minute, return the record if it was last_scheduled more than 1 minute ago”

If there is more than one record, records scheduled to occur more frequently will be handled first (so records with minute schedules are returned before records with daily schedules.

schedule_complete
Sets the record’s last_scheduled value to Time.now

Example

class ScheduledItem < ActiveRecord::Base
acts_as_scheduled
end

schedule_minute = ScheduledItem.new(:frequency => 1.minute, :last_scheduled => 2.seconds.ago)
schedule_minute.save

schedule_day = ScheduledItem.new(:name =>”day”, :frequency => 1.day, :last_scheduled => 25.hours.ago)
schedule_day.save

#returns thing_day because it was last_scheduled 25 hours ago
schedule_day = ScheduledItem.find_next_scheduled
schedule_day.do_some_stuff
schedule_day.schedule_complete
schedule_day.save

Posted in Plugins, Ruby, Ruby on Rails | No Comments »

Bad things done well: accepting dangerous input with Rails

Wednesday, April 2nd, 2008

For various reasons I need to be able to be able to accept some script input from the client.

The basic requirement is to be able to accept some Ruby code from the client in order to allow customisation of the HTML output from an RSS feed.

This is obviously a rather dangerous thing. I essentially need to allow arbitrary Ruby to be executed with an eval

However, in Ruby, we can run code in SAFE mode.

At Level 4:

Ruby effectively partitions the running program in two. Nontainted objects may not be modified. Typically, this will be used to create a sandbox: the program sets up an environment using a lower $SAFE level, then resets $SAFE to 4 to prevent subsequent changes to that environment

The core of my approach is to create a new Thread, set the SAVE level to 4 and call a method.

feed = FeedNormalizer::FeedNormalizer.parse(open(self.url))
thread = Thread.start {
$SAFE = 4
html = safe_method(feed, script)}
}
thread.join #wait for the thread to finish

The safe_method itself does a sanity check on the safe level. The method takes a feed object and a script - the script is processed using eval and because the feed object is in the context, the script has access to it. However, the safe level prevents any malicious code from attempting to use Ruby magic and meta-programming to gain access to variables outside the thread or any globals

def safe_method(feed,script)
if ( $SAFE < 4 )
raise “SecurityException: attempting to execute UNSAFE script”
end

html = “”
eval(script)
return html
end

The user can then pass in code that looks like:

html << “<h2>#{feed.title}</h2>”
html << “<ul>”
feed.entries.each do |entry|
html << “<li><a href=\”#{entry.urls.first}\”>#{entry.title}</a></li>”
end
html << “</ul>”

And the feed is processed without (too much) risk.

Posted in Code, Programming, Ruby, Ruby on Rails | 3 Comments »

But will it scale?

Wednesday, March 12th, 2008

I am very pleased to announce the availibility of the Hypothetical Megastructure “but will it scale” t-shirt.

The t-shirt provdes the wearer with the following powers:

Effortlessly win any technical discussion instantly!
Impress your friends!
Immediately dismiss any rival language or framework!

“BUT WILL IT SCALE“?

Available in LARGE, EXTRA-LARGE, GRID, and the apparently defunct N-TIER.

I like to wear mine in a cluster (simply buy two or more t-shirts and wear simultaneously).

Posted in Ruby, Ruby on Rails, Scalability, Software Engineering, Technology, Web 2.0 | 6 Comments »

backup_fu: making Amazon S3 backups simple

Sunday, February 17th, 2008

My favourite new plugin for Ruby on Rails is backup_fu.

backup_fu makes managing Amazon S3 backups really simple.

I have been running my own Rake Task for MySQL Backup to Amazon S3, but I’ve switched my projects over to backup_fu instead because it has much better control over your backups and will even backup stored files.

I’ve also created a patch for backup_fu that allows you to specify the mysqldump options. It should get rolled into an upcoming release, but if you would like it sooner, just contact me at toby…@info-architects.net.

Posted in Amazon S3, MySQL, Ruby, Ruby on Rails, Software Engineering | No Comments »

CodeIgniter: I Don’t Hate It

Thursday, February 14th, 2008

The unfortunate tragedy of my life is that I don’t get to develop in Ruby on Rails all the time. No, unfortunately for me, a large number of my clients need work done in PHP.

Which, as already indicated in several previous nuanced discussions, I hate.

I mean, really really HATE.

But that’s not the point of this post.

After being seriously burnt by the twin miseries of CakePHP’s poor documentation and desperately misguided attempt to mimic Rails I went looking for a new PHP MVC framework for a recent project.

Crucial requirements:

lack of opinion
simplicity
good documentation
understands PHP is not Ruby

I really wanted something that was pure VC, leaving out the M.

Views, Controllers and Models can go to hell.

PHP’s complete lack of dynamicism (and yes, I know PHP 5 has a crack at it, but whatever) means any attempt at Hibernate or Rails-style ORM is doomed to failure. And after screaming at CakePHP every time a finder returns an array of nested hashes of arrays of hashes and you can never work out how to just iterate through the records I’ve gone back to ADODB. You run a query and are returned a Record Set. I know this just reveals how long I spent in the late 90s hacking ASP, but if any language was still living in the late 90s, it’s PHP. And it’s actually quite good at it.

Where was I?

Right. Clean View/Controller mechanism. No Models.

Enter CodeIgniter.

It’s incredibly simple, the only assumption it makes is that you may never need most of the stuff it includes, so everything is an option, and it has great documentation.

CodeIgniter: I Don’t Hate It.

If you really have to use PHP, it’s worth a look.

Posted in CakePHP, CodeIgniter, PHP, Programming, Ruby, Ruby on Rails, Software Engineering, Technology | 12 Comments »

Installing Rails, Mongrel on Slicehost with Ubuntu “Gutsy Gibbon”

Monday, February 4th, 2008

Links for future reference on Installing Rails, Mongrel on Slicehost with Ubuntu “Gutsy Gibbon”

Slicehost Configuration Guide:

Posted in Capistrano, Deployment, Deprec, Ruby, Ruby on Rails, Slicehost | 1 Comment »

Why Rails is better than whatever it is you use: ToDo List in 5 Lines

Tuesday, December 18th, 2007

Rob Mayhew prepared this ToDo List Tutorial

rails todo
cd todo
rake db:create:all
script/generate scaffold Todo title:string body:text done:boolean due:datetime
rake db:migrate

Update: This code pretty much also provides you with a REST API.

Posted in Programming, Ruby, Ruby on Rails, Software Engineering, Web 2.0 | 3 Comments »

Rails 2.0 has been released

Saturday, December 8th, 2007

Oh yes: Rails 2.0 has been released

For some tips on moving your codebase to version 2.0:

I’ll be moving some of my projects and will be blogging about my experiences.

Posted in Ruby, Ruby on Rails | No Comments »

RailsCamp 2.0

Wednesday, November 21st, 2007

RailsCamp is on this weekend. 40 uber-geeks gathered to immerse themselves in Ruby On Rails.
It should be pretty cool.

I haven’t prepared any materials, but might present something on Amazon Web Services - I did this for the Melbourne Ruby User Group a little while ago.

Posted in Code, Development, Programming, Ruby, Ruby on Rails, Software Engineering, Technology, Web 2.0 | No Comments »

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