Building a CLI Gem Walkthrough

This video walks through the process of planning and building a CLI gem. There will be more videos on the process of building a more complex gem as well as on refactoring and improving a CLI gem.

Objectives

1. Planning your application
2. Generating and setting up a basic gem
3. Basic CLI User interface
4. Setting up your Objects
5. Setting up your Scraper
6. Bring it all together!

Video

Summary

• Planning the gem.
• Beginning the building process.
  • Setting up or generating the basic structure of the gem.
  • Creating and stubbing out the executable file.
• requiring files with require and require_relative.
• Coding the CLI class — our controller.
  • Stubbing out the CLI class with hard-coded return data.
  • Creating the menu.
• Setting up our Deal class.
  • #today method to return today's deals.
  • Stubbing out our first Deal instances with hard-coded data.
  • Setting up the Deal class attributes.
• Testing our data in the console.
• Wire up our menu with conditional logic to work with our array of deals.
  • Iterate over and display deals.
  • Fix spelling on #availability.
• Setting up our scraper class — should we use a Deal class method or a standalone class?
  • Set up Deals#scrape_deals method.
• Adding gem dependencies to the app.
  • Add dependencies to gemspec.
  • Development dependencies or runtime dependencies?
• Code individual scrape methods for each site.
  • Use CSS selectors to scrape desired information.
  • Create new Deal objects and set the attributes based on the scraped info.
  • Update logic for #availability.
• Final thoughts and tips on the building process.

Code

• Daily Deals Gem repository

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