Common Anti-Patterns in CLI Data Gem

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Common Anti-Patterns in CLI Gem Application

This video walks through the process of refactoring a CLI Gem fixing common anti-patterns in CLI Gem applications

Objectives

1. Define anti-patterns

2. Pinpoint flaws in Gem

3. Zipper Pattern

4. Format user output

5. Decouple scraping functionality

6. Create Instances of our Model/Class

Video

<iframe width="100%" height="720" src="https://www.youtube.com/embed/cbMa87oWv08?rel=0&showinfo=0" frameborder="0" allowfullscreen></iframe>

[MP4](Find learn s3 source?)

Summary

• what do we mean by anti-patterns

• explain our gem functionality

• explain our classes

• find flaws in gem

• bunch of different arrays of data instead of unified objects

• explain zipper pattern

• too many calls to website

• We never instantiate instances of our class

• a ton of scraping methods in our story object

• hard coded maximum number for user input

• using each instead of collect

• examine app in pry

• fix formatting for output

• build functionality to scrape individual story

  • make it work using our zipper pattern

  • fix undefined method error

  • output scraped story

• move scraping logic to a Scraper class

  • change class methods to instance methods

  • define responsibility of Scraper class

  • scrape individual li tags of stories

  • grab individual attributes of that story with css selectors.

  • use those individual story details info to create a new story instance

• add functionalty to Story class to keep track of all its instances

• test scraper functionality

  • last article causes an error

  • use rescue to pinpoint source of error

  • create logic to prevent the error stemming from different tags in final article

• implement our new functionality throughout the app

  • use our new logic to obtain and output the stories in cli class

  • add functionality to scrape individual article

• realize how efficient our app is now that we've utilized Object Orientation

• a story object now has power and convenient methods

• commit and examine github diff post refactor

Code

Original Code

Refactored Code

Diff

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