Arup Rakshit aruprakshit

Optimistic Locking assumes that a database transaction conflict is very rare to happen. It uses a version number of the record to track the changes. It raise an error when other user tries to update the record while it is lock.

usage

Just add a lock_version column to the table you want to place the lock and Rails will automatically check this column before updating the record.

Pessimistic locking assumes that database transaction conflict is very likely to happen. It locks the record until the transaction is done. If the record is currently lock and the other user make a transaction, that second transaction will wait until the lock in first transaction is release.

usage

Redux Selector Pattern

Imagine we have a reducer to control a list of items:

function listOfItems(state: Array<Object> = [], action: Object = {}): Array<Object> {
  switch(action.type) {
    case 'SHOW_ALL_ITEMS':
      return action.data.items
    default:

Should be work with 0.18

Destructuring(or pattern matching) is a way used to extract data from a data structure(tuple, list, record) that mirros the construction. Compare to other languages, Elm support much less destructuring but let's see what it got !

Tuple

myTuple = ("A", "B", "C")
myNestedTuple = ("A", "B", "C", ("X", "Y", "Z"))

Proxy cache passes GET instead of HEAD to upstream... so we have a 403.

This version include these fixes.

Remove $request_method from $string_to_sign and pass static string "GET" instead
Remove proxy_buffering directive for allowing the nginx cache

Keyboard shorcuts

CTRL + SHIFT + p: Command panel
CTRL + p: File search
CTRL + r: Method search inside current file
CTRL + g: Go to line #
CTRL + SHIFT + [: Fold code
CTRL + SHIFT + ]: Unfold code
ALT + SHIFT + 2: Double column/file mode
ALT + SHIFT + 1: Single column/file mode

In Rails 3

NOTE: This post now lives (and kept up to date) on my blog: http://hakunin.com/rails3-load-paths

If you add a dir directly under app/

Do nothing. All files in this dir are eager loaded in production and lazy loaded in development by default.

	# In app/helpers/users_helper.rb

	require_relative 'users_helper/greet'

	module UsersHelper
	module Internals
	end
	private_constant :Internals
	include Internals

	class Wrong
	def method_missing(m, *)
	if m =~ /\Ahello_(.+)\z/
	puts "Hello, #{$1.capitalize}"
	else
	super
	end
	end
	end

	original_solution.files.each do \|original_file\|
	f = original_file.dup
	f.remote_name_url = original_file.name.url
	new_solution.files << f
	end

	// Sublime Text - Build System for Javascript
	{
	"cmd": ["node", "$file"],
	"selector": "source.js"
	}