kadru

Install nginx

$ brew install nginx

Edit nginx.conf

$ vim /usr/local/etc/nginx/nginx.conf

kadru

Order of Rails Controller Callbacks

Rails 4.x

Started GET "/" for 127.0.0.1 at 2017-05-19 14:17:18 +0200
  Processing by WelcomeController#index as HTML
    prepend_around_action
    prepend_before_action
 before_action

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require 'net/ldap'


module Ldap

  LDAP_SERVER_IP = 'buzon.uach.mx'.freeze
  #LDAP_USERNAME = 'ldap_username'
  #LDAP_PASSWORD = 'ldap_password'

  #Obtiene el nombre mediante su cuenta de usuario

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#the do´s
2.hours.ago # => Thu, 27 Aug 2015 14:39:36 AFT +04:30
1.day.from_now # => Fri, 28 Aug 2015 16:39:36 AFT +04:30
Time.zone.parse("2015-08-27T12:09:36Z") # => Thu, 27 Aug 2015 16:39:36 AFT +04:30
Time.current # => Thu, 27 Aug 2015 16:39:36 AFT +04:30
Time.current.utc.iso8601 # When supliyng an API ("2015-08-27T12:09:36Z")
Time.strptime("2015-08-27T12:09:36Z", "%Y-%m-%dT%H:%M:%S%z").in_time_zone # If you can’t use Time.zone.parse (Thu, 27 Aug 2015 16:39:36 AFT +04:30)
Date.current # If you really can’t have a Time or DateTime for some reason (Thu, 27 Aug 2015)
Date.current.in_time_zone # If you have a date and want to make the best out of it (Thu, 27 Aug 2015 00:00:00 AFT +04:30)
#the don´ts

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    db:create #Creates the database for the current RAILS_ENV environment. If RAILS_ENV is not specified it defaults to the development and test databases.

    db:create:all #Creates the database for all environments.
    db:drop #Drops the database for the current RAILS_ENV environment. If RAILS_ENV is not specified it defaults to the development and test databases.

    db:drop:all #Drops the database for all environments.
    db:migrate #Runs migrations for the current environment that have not run yet. By default it will run migrations only in the development environment.
    db:migrate:redo #Runs db:migrate:down and db:migrate:up or db:migrate:rollback and db:migrate:up depending on the specified migration. I usually run this after creating and running a new migration to ensure the migration is reversable.
    db:migrate:up #Runs the up for the given migration VERSION.

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Transactions

As your business logic gets complex you may need to implement transactions. The classic example is a bank funds transfer from account A to account B. If the withdrawal from account A fails then the deposit to account B should either never take place or be rolled back.

Basics

All the complexity is handled by ActiveRecord::Transactions. Any model class or instance has a method named .transaction. When called and passed a block, that block will be executed inside a database transaction. If there's an exception raised, the transaction will automatically be rolled back.

Example

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HTTP status code symbols for Rails

Thanks to Cody Fauser for this list of HTTP responce codes and their Ruby on Rails symbol mappings.

Status Code Symbol
1xx Informational
100 :continue
101 :switching_protocols
102 :processing

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#Date Formatting I
'%Y' #Year with century (e.g. 2015, 1995, etc)
'%m' #Month of the year, zero-padded (01..12)
'%B' #The full month name (e.g. January)
'%b' #The abbreviated month name (e.g. Jan)
'%d' #Day of the month, zero-padded (01..31)
'%j' #Day of the year (001..366)

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#Safe navigation operator
if account && account.owner && account.owner.address
  #your code here
end
#could be rewritten like
account&.owner&.address

#more examples
account = Account.new(owner: nil) # account without an owner
#

kadru

#get env variables of a process
sudo xargs --null --max-args=1 < /proc/<pid>/environ

#get command of a process
ps -fp <pid>
cat /proc/<pid>/cmdline