Ivan Kornilov vano468

Sessions and Conversations

HTTP is a stateless protocol. Sessions allow us to chain multiple requests together into a conversation between client and server.

Sessions should be an option of last resort. If there's no where else that the data can possibly go to achieve the desired functionality, only then should it be stored in the session. Sessions can be vulnerable to security threats from third parties, malicious users, and can cause scaling problems.

That doesn't mean we can't use sessions, but we should only use them where necessary.

Adding, Accessing, and Removing Data

TCP client and multithreaded server in 14 lines of Ruby code

Server:

require "socket"
server = TCPServer.open(2626)
loop do
	Thread.fork(server.accept) do |client| 
 client.puts("Hello, I'm Ruby TCP server", "I'm disconnecting, bye :*")

tmux cheat sheet

(C-x means ctrl+x, M-x means alt+x)

Prefix key

The default prefix is C-b. If you (or your muscle memory) prefer C-a, you need to add this to ~/.tmux.conf:

remap prefix to Control + a

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

Lambda: standard

# Creating a lambda
l = lambda { |name| "Hi #{name}!" }

# Executing the lambda
l.call("foo") # => Hi foo!

	=Navigating=
	visit('/projects')
	visit(post_comments_path(post))

	=Clicking links and buttons=
	click_link('id-of-link')
	click_link('Link Text')
	click_button('Save')
	click('Link Text') # Click either a link or a button
	click('Button Value')

	-- show running queries (pre 9.2)
	SELECT procpid, age(clock_timestamp(), query_start), usename, current_query
	FROM pg_stat_activity
	WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%'
	ORDER BY query_start desc;

	-- show running queries (9.2)
	SELECT pid, age(clock_timestamp(), query_start), usename, query
	FROM pg_stat_activity
	WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'

	# This is a skeleton for testing models including examples of validations, callbacks,
	# scopes, instance & class methods, associations, and more.
	# Pick and choose what you want, as all models don't NEED to be tested at this depth.
	#
	# I'm always eager to hear new tips & suggestions as I'm still new to testing,
	# so if you have any, please share!
	#
	# @kyletcarlson
	#
	# This skeleton also assumes you're using the following gems:


	# 1) Create your private key (any password will do, we remove it below)

	$ cd ~/.ssh
	$ openssl genrsa -des3 -out server.orig.key 2048


	# 2) Remove the password

	$ openssl rsa -in server.orig.key -out server.key

	gem install do_postgres -- \
	--with-pgsql-server-dir=/Applications/Postgres.app/Contents/Versions/9.3 \
	--with-pgsql-server-include=/Applications/Postgres.app/Contents/Versions/9.3/include/postgresql/server