Matt Rohrer prognostikos

Quiz time!

What does the dot mean in in StringIO.new, what does the hash mean in StringIO#puts?
How do you make a String literal?
How do you make a String without using a literal?

This is an HTTP request, it is a String that is sent across a Socket, which your program can read from as if it were a file or $stdin.

01 POST /users/5?omg=wtf&amp;bbq=lol HTTP/1.1\r\n

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!

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curl https://api.balancedpayments.com/debits -XPOST -u ak-test-2yK59ihwoOOk0S6wsg77iMGzLGnGxiohB: -d "source[number]=4444444444444448" -d "source[expiration_month]=12" -d "source[expiration_year]=2016" -d amount=100

{
  "errors": [
    {
      "status": "Payment Required",
      "category_code": "card-declined",
      "additional": "Account Frozen",
      "status_code": 402,

Trouble-Free Bundler

Every couple of weeks, I hear someone complaining about some difficulties with Bundler. Yesterday, it happened twice. But somehow I just never have those difficulties. I'm not saying Bundler is perfect; certainly in its early days it wasn't even close. But for the past two years it's been incredibly solid and trouble-free for me, and I think a large part of the reason is the way I use it. Bundler arguably does too much, and just as with Git, a big part of it is knowing what not to do, and configuring things to avoid the trouble spots.

	#!/bin/bash

	# You need: curl, jq, and ipcalc to run this.
	# You should already have cut, sort and uniq if you're on OS X or Linux.

	RANGES=$(curl -s https://ip-ranges.amazonaws.com/ip-ranges.json \| jq .prefixes \| jq '.[] \| select(.region=="us-east-1")' \| jq 'select(.service=="EC2")' \| jq .ip_prefix \| cut -d '"' -f 2 \| sort \| uniq)

	for range in $RANGES
	do
	MIN=$(ipcalc -bn $range \| grep "HostMin" \| cut -d ':' -f 2)

	require 'uri'

	hostname = "(?:(?:[\\w\\-]+\\.)+[[:alpha:]]{2,})"
	host = "(?:#{hostname}\|#{URI::DEFAULT_PARSER.pattern[:IPV4ADDR]}\|#{URI::DEFAULT_PARSER.pattern[:IPV6ADDR]})"
	server = "//(?:#{URI::DEFAULT_PARSER.pattern[:USERINFO]}@)?#{host}(?::\\d*)?"
	absolute_path = "(?:#{URI::DEFAULT_PARSER.pattern[:ABS_PATH]})?"
	query = URI::DEFAULT_PARSER.pattern[:QUERY]

	http_uri_regex = Regexp.new("\\A(?:http\|https):(?:#{server}#{absolute_path})(?:\\?(?:#{query}))?\\z", Regexp::EXTENDED, 'N')

	-- Functions to create and draw histograms with PostgreSQL.
	--
	-- psql# WITH email_lengths AS (
	-- -# SELECT length(email) AS length
	-- -# FROM auth_user
	-- -# LIMIT 100
	-- -# )
	-- -# SELECT * FROM show_histogram((SELECT histogram(length, 0, 32, 6) FROM email_lengths))
	-- bucket \| range \| count \| bar \| cumbar \| cumsum \| cumpct
	-- --------+-------------------------------------+-------+--------------------------------+--------------------------------+--------+------------------------

	#!/bin/sh
	# linux firewall/forwarding
	modprobe iptable_nat
	echo 1 \| tee /proc/sys/net/ipv4/ip_forward
	iptables -t nat -A POSTROUTING -s 10.10.10.1/2 -o eth0 -j MASQUERADE
	# install openvpn
	apt-get update && apt-get install -y openvpn
	cd /etc/openvpn/
	INSTANCE=$(curl http://169.254.169.254/latest/meta-data/public-hostname)
	openvpn --genkey --secret ${INSTANCE}.key

	---
	rvm:
	- 2.0.0

	before_install:
	- "echo 'gem: --no-document' > ~/.gemrc"
	- "echo '--colour' > ~/.rspec"
	- gem install fog
	- "./script/travis/bundle_install.sh"
	- export DISPLAY=:99.0

	#!/bin/bash

	aws cloudformation create-stack --stack-name test-vpc --template-body file://vpc.json