Category Archives: Programming

Nothing beats Dash for quickly checking dev documentation

Dash is an incredibly useful Mac app that I’d highly recommend all developers check out. It lets you instantly search developer documentation (devdocs) straight from your computer:

Dash.gif

You can configure it to check only the devdocs you use on a regular basis. For example, I have Dash configured to search the devdocs for SaaS, Rails 4, jQuery, HTML, jQuery UI, PHP, MySQL, CSS, JavaScript, Ruby, WordPress, Node.js, Lo-Dash, R, and D3.js. It supports over 150+ sets of documentation and also lets you generate your own. Dash also keeps the documentation automatically up to date as it changes.

If you want to constrain your search to a specific set of devdocs, you can prefix your search such as ruby:gsub and it will only check the Ruby docs.

I also set Cmd+Shift+D to load Dash so that I can pull it up while I’m coding, perform a search, and Alt+Tab back to Sublime without ever touching the mouse.

It’s free to try and $24.99 to buy. Give it a shot and rejoice that you’ll never again have to Google for documentation.

Using the ESLint Gem in Rails

ESLint is a popular linting utility for JavaScript. In this post I’ll show you how I use it in a Ruby on Rails app.

A quick intro to ESLint

ESLint lets  you specify how you want to style your JavaScript and it will then check your code and report any issues. For example, if you use the quotes rule to specify that you want to use single quotes everywhere, ESLint will check whether that’s true and report back anywhere you accidentally used double quotes.

Whether you’re a part of a team or working on a project by yourself, ESLint is a great way to ensure clean, consistent code and identify bugs before they ever make their way into production.

The ESLint Gem

Jon Kessler and Justin Force created a handy ESLint gem for Rails. You simplify create a configuration file in config/eslint.json, execute rake eslint:run, and it will check your application.js file for any issues.

If you’re looking for a solid eslint config file, check out the one we at Automattic use for Calypso.

Customing the workflow

I wound up customizing how I use the the gem for two reasons:

  1. The gem checks application.js which concatenates all of your JavaScript assets based on the manifest file. If your assets include third party scripts like jQuery, ESLint will wind up linting those as well which you probably don’t care about.
  2. Similarly, because all of your JavaScript files are concatenated in application.js, the line numbers that ESLint spits out in its report don’t correspond to the line numbers in the individual files, making it difficult to pinpoint the offending lines of code.

To account for this, I first moved all of the third party JavaScript files out of app/assets/javascripts and into app/assets/javascripts/lib. With them moved out of the javascripts directory, I then wrote a new Rake task that takes advantage of the gem’s ability to lint a single file:


namespace :lint do
task run: :environment do
js_dir = "#{Rails.root}/app/assets/javascripts"
Dir.chdir(js_dir)
# No directories and no application.js
files = Dir.glob('*').delete_if{ |f| File.directory?(f) || f == 'application.js' }
files.each do |file|
puts file
# There is a likely way to do this with Rake::Task's `invoke` and `reenable` methods
# but I couldn't figure out how to get it to check more than the first file.
puts `rake eslint:run[#{js_dir}/#{file}]`
end
end
end

view raw

lint.rake

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With this in place, you can run rake lint:run and it will iterate over each of your JavaScript files within the javascripts directory and execute ESLint on each one:

$ rake lint:run

account.js
48:5 low indent Expected indentation of 3 tab chrs but found 4
49:5 low indent Expected indentation of 3 tab chrs but found 4
50:5 low indent Expected indentation of 3 tab chrs but found 4

interface.js
612:3 slow quote-props Unnecessarily quoted property `class` found
613:28 low quote-props Unnecessarily quoted property `class` found
915:1 low valid-jsdoc Missing JSDoc parameter type for 'reason'

If you also use ESLint in your Rails project, I’d love to hear more about your setup.

A Ruby script to download a backup of your Heroku app’s Postgres database

A little over 5 years ago I shared a script that I had written to download a local backup of a Heroku app. Heroku’s CLI and its capabilities have changed a lot since then so I want to share an updated version for anyone who might find it useful.

You can check it out on Github: Heroku Postgres Backup Downloader.

For example, I have a cron job set up to generate a daily backup of Lean Domain Search that uses it:

$ ruby heroku-pgbackup-downloader.rb leandomainsearch "/Users/matt/Projects/LeanDomainSearch/Heroku Backups/"
Running backup script for leandomainsearch...
 Capturing a new backup...
  New backup id: b282
 Downloading new backup...
Done

Screen Shot 2015-11-27 at 9.16.28 AM.png

I’ve never had to use the backups and hopefully never will, but having them provides an extra layer of protection in case any of my sites are compromised and the data winds up corrupted or lost.

If you have a different backup strategy for your Heroku apps, I’d love to learn more – drop me a note or leave a comment below. Thanks!

TetriNET Bot Source Code Published on Github

A few years ago I wrote about a bot I built in high school to play an online multiplayer Tetris game called TetriNET. The tl;dr is that I got into TetriNET with some friends, built a bot to automate the play, and eventually entered my school’s science fair with it and wound up making it to internationals. As you can imagine, I was pretty cool in high school…

Anyway, when I wrote the post Github was just getting off the ground and it didn’t even occur to me at the time to open source the code there; instead I just zipped up the Visual Basic Project (go VB6!) and linked to it from the post.

Happily, I have gained a little bit more experience with Git and Github since then so I took some to clean up the code (converting CRLF line endings to LF, spaces to tabs, etc) and finally published it.

You can check it out here if you’re curious: https://github.com/mattm/tetrinet-bot.

On that note, this is pretty much exactly what I looked like while checking out out my old code so keep in mind it was a long time ago :)…