Like Ryan Sonnek, I’ve dabbled with a few different ways to run background processes in my Ruby apps, even resorting to knocking together my own (far from perfect) solution. As Ryan says on his blog, many popular libraries have complicated interfaces and don’t “feel right”.

I tend to disagree, however, with his statement that every ruby background job solution sucks, and I’m sure he doesn’t really mean it. Although his offering, Backgrounded, is refreshingly simple and concise, it’s effectively just a wrapper for other solutions.

With Backgrounded, if you want a certain method to always run in the background, you can specify it like this:

class User
backgrounded :do_stuff

def do_stuff
# do all your work here
end
end

…and then just call that method in the normal way. Read More

Until recently, I had been using the Curb library for making HTTP requests with Ruby, and I must say I was fairly happy with it. Phillip Toland, on the other hand, wasn’t satisfied with Curb’s API and the fact that it is tricky to modify (being implemented mainly in C). So, he came up with an alternative called Patron, written as much as possible in Ruby.

Patron is based on libcurl, just like Curb, but it aims to provide a simpler interface whilst still taking advantage of libcurl’s strengths. To use Patron you can instantiate a Session object with your desired options:

sess = Patron::Session.new
sess.base_url = “http://search.twitter.com/”

…and then call methods against that session to perform your GET, HEAD, PUT, POST or DELETE operations. Read More

Siren is a JSON and JSONQuery interpreter for Ruby by James Coglan. Before I dive into talking about Siren, a little bit of background:

JSON is a lightweight, human-friendly data interchange format, for which there is already good Ruby support in the form of the json gem. JSONQuery was originally added as part of the dojo javascript toolkit and provides querying tools for JSON such as filtering and sorting etc. (check out this article on SitePen for more details). You can also find a stand-alone port of JSONQuery on Github.

Anyway, Siren lets you run queries against any type of Ruby object. Read More

With people occasionally talking about “Code vs. Data”, it only makes sense that you should be able process over code as you would a string. Sexp Path is a code processing tool that allows you to search over and process Ruby code in the form of S-Expressions.

For those who don’t know, an S-Expression (or simply, a “sexp”) is an iterable way of representing code or data. Using Ryan Davis’ Parse Tree, you can parse Ruby files and process over them using Sexp Path. It’s a bit like like XPath or regular expressions for your code.

The foundation of Sexp Path is the query, formed with Q?{ … Read More

Why’s Markaby is a really convenient bit of Ruby for generating HTML in your applications, rather than having to fiddle about with string interpolation or ERb, tangling together HTML and Ruby.

However, Markaby can be slow compared with other options like Erubis or HAML. Magnus Holm has been working on an alternative solution called Parkaby, which uses ParseTree for improved performance (coming out up to 20 times faster than Markaby in Magnus’s tests).  Parkaby uses near-identical syntax to Markaby, so you still get to write beautiful ruby code for building your HTML.

Parkaby {
html {
head {
title “happy title”
}
body {
h1 “happy heading”
a “a link”, “href” => “url”
}
}
}

Magnus admits that Parkaby is currently only experimental, and that there’s room for more optimization, but I think he might be onto something. Read More

When running a Ruby daemon which executes code in a loop, if the process is killed while something is happening then problems can occur if the code doesn’t handle all the exceptions properly or if the loop isn’t broken cleanly. RobustThread is a Ruby class by Jared Kuolt for the creation of threads, which helps to alleviate this problem.

RobustThread lets you set up loggers, exception handlers and callbacks for threads, exposing the actual thread via an attribute.  By default, it logs to the standard output, but this is configurable by using a Logger object.

You can apply labels to loops or threads, which can be useful for logging and debugging.  Read More

Anemone is a free, multi-threaded Ruby web spider framework from Chris Kite, which is useful for collecting information about websites. With Anemone you can write tasks to generate some interesting statistics on a site just by giving it the URL.

Its only dependency is Nokogiri (an HTML and XML parser). Other than that, you just need to install the gem to get started using Anemone’s simple syntax which, among other things, allows you to tell it which pages to include (based on regular expressions) or define callbacks.

This example taken from Anemone’s homepage prints out the URL of every page on a site:

require ‘anemone’

Anemone.crawl(“http://www.example.com/”) do |anemone|
anemone.on_every_page do |page|
puts page.url
end
end

The bin folder in the project contains some more in-depth examples, including tasks for counting the number of unique pages on a site, the number of pages at a certain depth in a site, or a list of urls encountered.  Read More