CoinRocket

This is a cryptocurrency watchlist application built with Ruby on Rails.

Top Features

• Live prices, list top 200+ cryptocurrencies by market cap.

• Search and filter cryptocurrencies by name

• Users can view the details of a cryptocurrency.

• Users can create an account and log in to the application.

• Logged in Users can create different Watchlists.

• Users can add and remove cryptocurrencies to their watchlists.

Step by Step to Build

1. Gathering and Storing Data

APIs

• CoinRanking API.It is a free API that provides cryptocurrency data.
• Faker Gem. It is used to generate fake users.

Database ERD Diagram

User Table

Column Name	Data Type
email	string
password	string

Cryptocurrency Table

Column Name	Data Type
uuid	string
symbol	string
name	string
color	string
icon_url	string
market_cap	string
price	string
listed_at	integer
tier	integer
change	string
rank	integer
sparkline	text
low_volume	boolean
coinranking_url	string
volume_24h	string

Watchlist Table

Column Name	Data Type
user_id	references
name	string

CryptocurrenciesWatchlists (Join Table)

Column Name	Data Type
cryptocurrency_id	references
watchlist_id	references

AR Models

rails generate model Cryptocurrency uuid:string symbol:string name:string color:string icon_url:string market_cap:string price:string listed_at:integer tier:integer change:string rank:integer sparkline:text low_volume:boolean coinranking_url:string 24h_volume:string

rails generate model Watchlist user:references name:string

rails generate model CryptocurrenciesWatchlists cryptocurrency:references watchlist:references

Use Devise to generate the User model.

rails generate devise:install
rails generate devise User
rails generate devise:views

Run the migrations.

rails db:migrate

Model Associations and Validations

class User < ApplicationRecord

 has_many :watchlists
 has_many :cryptocurrencies, through: :watchlists

devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :validatable
end


class Cryptocurrency < ApplicationRecord
  has_many :cryptocurrencies_watchlists
  has_many :watchlists, through: :cryptocurrencies_watchlists

  validates :name, presence: true
  end

class Watchlist < ApplicationRecord
  belongs_to :user
  has_many :cryptocurrencies_watchlists, dependent: :destroy
  has_many :cryptocurrencies, through: :cryptocurrencies_watchlists

  validates :user_id, presence: true
  validates :name, presence: true
end

class CryptocurrenciesWatchlist < ApplicationRecord
  belongs_to :cryptocurrency
  belongs_to :watchlist

  validates :cryptocurrency_id, presence: true
  validates :watchlist_id, presence: true
end

2. Web Site Navigation

• Home Page - Information
• About Page - About the APIs and Author
• Coins Page - List all the cryptocurrencies
• Coin Details Page - Show the details of a cryptocurrency
• Sign Up Page - Create an account
• Log In Page - Log in to the application
• Watchlist Page - Show all the cryptocurrencies in the watchlist
• Single Watchlist Page - Show all the cryptocurrencies in the watchlist

Coins page -> Coin details page -> Add to watchlist -> Watchlist page -> Show all coins in the watchlist -> Show all watchlists

3. Pagination and Search

• Use the kaminari gem to add pagination to the index page.

• Easy to search and filter cryptocurrencies by name and rank.

• Search a cryptocurrency by name, symbol in Top100 or All or Potential coins.

4. Markup and Design

• Bootstrap 5
• Erb Conditional (if user is logged in, show the watchlist)
• HTML Validation

5.Source Control

Use Git and GitHub to track changes and manage version control.

6. Deployment

Haven't deployed yet. Plan to deploy to Heroku.

Resources

• Ruby on Rails 實戰聖經 Good ebook to learn Ruby on Rails.

• Learn Ruby on Rails - Full Course FreeCodeCamp Youtube video.

• Sample: Board Game A sample project built with Ruby on Rails and deployed to Fly.io.

Pitfalls

• Many to many association between Cryptocurrency and Watchlist. If you want to add a cryptocurrency to a watchlist, you need to create a CryptocurrenciesWatchlist object. It you want to remove a cryptocurrency from a watchlist, you need to destroy the CryptocurrenciesWatchlist object.

• Devise gem If you already have a User model, you need to run the migration to add the devise columns to the User table.

• Search in the every page (navbar) I add the search form in the navbar, so I need to add the search function in every controller.

• .... A lot of pitfalls to learn.