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Rails

Rails Routes

# basic syntax
get 'home/index', to: 'home#index' # localhost:3000/home/index
get 'home/index' # localhost:3000/home/index

# set default controller for home page
root 'home#index'
root to: 'home#index'

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Database Operations

rails db # run sql
rails console # run rails

Associations

One to One

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Generator

rails generate [model|controller|resource|scaffold] [name]
rails destroy [model|controller|resource|scaffold] [name]

Model

rails g model hello

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Install

• Install rbenv
  • brew install rbenv
  • rbenv init
• Install ruby
  • rbenv install 2.6.3
  • rbenv global 2.6.3
• Install rails
  • export GEM_HOME="$HOME/.gem"
• gem install rails -v 5.2.3

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• DB CLI
• Helpers
• Field Types
• Column Modifiers
• Migaration Generator
  • AddColumnToTable
  • RemoveColumnFromTable
  • CreateTable
  • AddModelRefToModel
• CreateJoinTableTable1Table2

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Model Validation

• Validations are used to ensure that only valid data is saved into your database.

Types of Validation

• Database constriants: database-dependent, testing and maintenance difficult
• Client-side validation: unreliable, immediate feedback on the client-side
• Controller-level validation: difficult to test and maintain, controller should be slim

Method Trigger Model Validation

• create and create!
• save and save!

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Root

# kitten's instance method
root to: "kitten#index"

Resources (with ID)

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Rails Naming Convention

General Ruby Convention

• Class Name: CamelCase
• Methods: snake_case
• Variables: snake_case
• method?: will return boolean anyway
• method!: will throw exception if possible
• class::method: class method
• class#method: instance method

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import re,pymongo,time,os
import pandas as pd
import warnings; warnings.simplefilter('ignore')
from fontTools.ttLib import TTFont
from fontTools.unicode import unichr
from config import *
from pyquery import PyQuery as pq
from aip import AipOcr
from PIL import Image