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

Define anti-patterns
Pinpoint flaws in Gem
Zipper Pattern
Format user output
Decouple scraping functionality
Create Instances of our Model/Class

Video

[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

PreviousCLI Data Gem Walkthrough: Creating a CLI Scraper Gem NextStudent Example 1: Refactoring CLI Gem

Last updated 5 years ago

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

Define anti-patterns

Pinpoint flaws in Gem

Zipper Pattern

Format user output

Decouple scraping functionality

Create Instances of our Model/Class

Video

[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

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