Roblog

Command-line purging of Varnish caches

Varnish, the HTTP proxy, is a fantastic tool. Here’s a way to purge cached pages from the command line, a task I find myself wanting to do frequently.

A Caching Analogy

Explaining caching is hard; here’s an attempt.

Ruby regular expressions: the /o modifier

An explanation of the little-used – but handy-to-know – o modifier to Ruby’s regular expressions.

Real progress in long-running command-line scripts

Sometimes, you write Ruby scripts that take a long time to execute. Here’s how to show progress to your scripts’ users – part two in a series, this time showing how to display real progress to users.

Faking progress in long-running command-line scripts

Sometimes, you write Ruby scripts that take a long time to execute. Here’s how to show progress to your scripts’ users – part one in a series, this time dealing with how to show indeterminate, faked progress to reassure users that something is happening.

Persisting data in Ruby with PStore

Ruby comes with a powerful persistent storage system that’s backed by flat files and handles concurrent access and transactions out of the box – stuff you’d expect to need a database for. It’s criminally underused, and it’s called PStore. Never roll your own file locking code again!

Paths aren't strings

If you find yourself passing around lots of file paths in your Ruby scripts, you should save yourself a headache and use Pathnames, not strings.

Nokogiri as a command-line tool

Most Rubyists are familiar with [Nokogiri][]. It’s a combination XML and HTML parsing tool most commonly used for “screen scraping”: that is, fetching a web page, and searching through it to extract information of interest. When a website you’re interested in doesn’t offer an API, it’s often the only way to extract information from it.