SimonHeeeee的博客

Testing# Gemfilegroup :development, :test do gem 1 gem 2 gem 3endgroup :development do gem 4 gem 5 gem 6end# spec folder# rails_helper.rb# spec_helper.rb# model folder# name_spec.rb# features folder# names_spec.rb# in m

Conditional Assignment Operatora ||= nil # => nila ||= 0 # => 0a ||= 2 # => 0If a is undefined or false, the assign b to a, otherwise do nothing

rails new nestedResourcesDemorails g scaffold User username:string passwrod_hash:stringrails g scaffold Post user:references title:string content:text# user.rbhas_many :post# post.rbbelongs_to :userrails db migraterails c@user = User.create

FormThe 
destination 
urlWhether 
the
 data
 is 
associated 
with
 a 
modelThe 
field
 namesThe 
field 
input
 typesThe
 display 
name
 of 
fieldsWith URL:<%= form_with url: '/login' do |form| %> <%= form.label :email %> <%= form.

server is already running.Solution: kill the serverkill -9 $(lsof -i tcp:3000 -t)

One-to-many and Many-to-many relationshipsrails g scaffold Department code:string name:stringrails g scaffold Course department:references code:integer title:string description:textrails db:migraterails g scaffold User first_name:string last_name:st

Scaffold GeneratorIt generates:Model/migrationcontoller file and implementationthe entire view folderall restful routesrails new blogDemonstrationcd blogDemonstration/rails g scaffold Post title:string content:textrails d scaffold Post# in

Blog projectSet up projectrails new Blog --db=postgresqlcd Blograils s -b 0.0.0.0# localhost:3000Home Pageget '/pages', to: 'pages#home' in routes.rbCreate pages_controller.rb in controllers folderclass PagesController < ApplicationControl

Data typesstringtextintegerfloatdecimaldatetimetimestamptimedatebooleanreferencesSQL -> ORM -> Arel# Common commandsUser.where(name: 'Simon')User.find_by(name: 'Simon')User.limit(2)User.order(id: :desc)# Chaining commandsPost.wh

RailsFundamental Rail Commands:rails new PROJECT_NAME # creat eall filesrails s -b 0.0.0.0 # boots up server, listen for request on port 3000Route -> Controller -> Viewdefine routeshandler methods in controllerwrite view templates in the

Content:LogicIntroductionConventionsRuby on Rails Logic*Browser* <--request/response--> *Server* --request_info--> *Routing* ^ | | Params + Methods | | HTML + Assets V

Network4 networking layerslink layer: physical mediadirection connections between machinespacket-basedinternet layerwho do I want to talk to?Internet Protocol (IP) addressIPv4 (32-bit) and IPv6 (128-bit)how do I get messages to/from them

OOPTable of contentsClass declarationInstance variables and methodsConstructor method initializeInstance variables and Instance MethodsReader/Writer methodsOther instance mtehodsClass variables and Class methodsPrivate methodsDescribing metho

Ruby BasicsRuby is strongly typed and dynamically typedirb # run in command lineibj = object.newobj.classobj.class.superclassobj.methodsfoo = 5# Print string# "#{var}"p "Hello, #{foo}!"# Orp 'Hello, ' + foo.to_s + '!'def obj:talk(message,