Brewing My First Ruby CLI Gem
Like the beginning of any project, staring at a blank slate was by far the scariest part. First, I had to decide what I wanted my gem to be able to do, so I asked myself what I would find fun or helpful, or both. Beer is fun. Knowing which beers I absolutely must try is helpful. How about a gem that can access Beeradvocate’s top rated new beers? Yes, please!
Once I had my concept, I did a quick Google search for ways to create a Ruby gem. One of the top hits was Bundler, which generates all the files and dependencies I needed to get started (Bundler’s detailed read-along guide was easy to follow and really simplified what would otherwise have been a daunting process). After checking to make sure my version of bundler was up to date by running `bundle -v`, I was able to create my scaffold directory by running `bundle gem tap_rated_new_beers` (for recommendations on naming your gem, visit this guide at RubyGems.org). This step alone boosted my confidence because I now had the basic structure of my gem. Next step, set up my files!
I wanted make sure I followed the Single Responsibility Principle (SRP), so I created four files in which to write my code:
- lib/tap_rated_new_beers.rb (This serves as my environment.)
- lib/tap_rated_new_beers/scraper.rb (This file contains all the code that scrapes information from Beeradvocate’s Top Rated Beer: New page.)
- lib/tap_rated_new_beers/cli.rb (This file contains all the code that makes my CLI work.)
- lib/tap_rated_new_beers/beer.rb (this file contains all the code that instantiates each beer and it’s attributes. It also contains my open_in_browser method, which enables the user to directly access a beer’s brewery from their terminal.)
Before going much further, I wanted to make sure that my environment was set up correctly, so I added some “fake” code to my lib/tap_rated_new_beers files and ran my executable file in my terminal. My executable file, bin/tap_rated_new_beers, contains the following:
#/usr/bin/env rubyrequire 'pry'
Success! My files and classes were able to communicate with each other. Now I could start brewing my TapRatedNewBeers::Scraper class.
Building my scraper methods ended up being more of a challenge than I was expecting. I knew that I wanted to provide my gem user with two levels of information:
- A list of the top rated new beers (by rank).
- Each beer’s score, number of ratings, style, ABV, availability, description (if provided), and the brewery’s name, location and website url.
This meant that I needed to create two scraper methods — one that would get the rank and name of each beer, and one that would get each beer’s unique information. I was able to scrape my first level of information by isolating the table that contained the rows I wanted to access, then I iterated through each row to get the rank and name of each beer.
table_row_nodes = self.index_url.css("table").css("tr")
table_row_nodes = table_row_nodes.slice(2, 50)
table_row_nodes.each do |beer_row|
rank = beer_row.css("td").text
name = beer_row.css("td").css("a").first.text
beer_url = beer_row.css("td").css("a").first.attributes["href"].value
temp_beer = TapRatedNewBeers::Beer.new(name)
temp_beer.rank = rank
temp_beer.beer_url = "https://www.beeradvocate.com"+ beer_url
My second scraper method needed to utilize the the beer_url for each beer to access the individual beer’s attributes. Most attributes were easy to access, but I had to apply some enumerable methods to isolate the ABV, availability and notes/description.
beer_page = Nokogiri::HTML(open(beer.beer_url))
beer.score = beer_page.css("div#score_box").css("span.BAscore_big").css("span.ba-ravg").text
beer.ratings = beer_page.css("div#score_box").css("span.ba-ratings").text
beer.style = beer_page.css("div#info_box.break").css("a").text
beer.brewery = beer_page.css("div#info_box.break").css("a").text
beer.location = beer_page.css("div#info_box.break").css("a").text + ", " + beer_page.css("div#info_box.break").css("a").text
beer.brewery_url = beer_page.css("div#info_box.break").css("a").attributes["href"].value
array = beer_page.css("div#info_box.break").text.split("\n\n")
array.find do |phrase|
beer.abv = phrase
beer.availability = phrase
beer.notes = array.last
After scraping all the information I needed, I started building out my TapRatedNewBeers::Beer class. I created an attr_accessor for each attribute and a class variable @@all set equal to an array in which to store each beer instance that could then be shared between classes. I also added the open_in_browser method that could be called in my TapRatedNewBeers::CLI class and enable the user to access each brewery’s website (I love this feature!).
attr_accessor :name, :rank, :beer_url, :brewery, :style, :abv, :ratings, :score, :location, :brewery_url, :availability, :notes
@@all = 
def initialize(name = nil)
@name = name
@@all << self
Last but not least, I need to build the working file of my gem: TapRatedNewBeers::CLI. This final step took the longest BY FAR. I think the most challenging method to get working was select_beer. I needed to be able to account for invalid user input, and that meant converting the rank associated with each beer from a string to an integer so I could then define valid input as being 1 to 50 (or the length of the array containing all the beers, in case I decide to change the number of beers provided in the future). Thankfully, I got some help figuring this out from my amazing cohort at the Flatiron School.
puts "Select the rank number of the beer you'd like to sample:".red.bold
input = gets.strip
if input.to_i.between?(1, TapRatedNewBeers::Beer.all.length)
beer = TapRatedNewBeers::Beer.all.find do |beer|
beer.rank == input
puts "Have you been drinking? Please try again.".red.bold
After many, many trials and errors, I finally had a user-friendly, error-free gem! All I had left to do was publish it and crack open a beer (selected off my tap_rated_new_beer list, of course). I created a RubyGems account and followed the steps in the Publishing Your Gem guide…
tap_rated_new_beers 🔥 gem push pkg/tap_rated_new_beers-0.1.0.gem
Pushing gem to https://rubygems.org...
Successfully registered gem: tap_rated_new_beers (0.1.0)
…and before I knew it I had 30 downloads! That alone makes the past week’s efforts well worth it.
You can sample my Ruby CLI Gem by typing the following prompts in your terminal:
gem install tap_rated_new_beersbin/tap_rated_new_beers