Pierre-Alexandre Kofron kofronpi

The introduction to Reactive Programming you've been missing

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

Migrating from Postgres 9.0/Postgis 1.5 to Postgres 9.2/Postgis 2.0 on Heroku

This may not be relevant to many, but it's a process that I just had to go through and it was a bit tricky to figure a smooth way to make it work.

The gist of it is that you must do the following:

Export your production database from heroku to your local machine
Create a new, blank database with Postgres 9.2 and PostGIS 2.0
Import your heroku database into the new local database running 9.2/2.0
Dump the new database and upload it to S3

Deploying a subfolder to GitHub Pages

Sometimes you want to have a subdirectory on the master branch be the root directory of a repository’s gh-pages branch. This is useful for things like sites developed with Yeoman, or if you have a Jekyll site contained in the master branch alongside the rest of your code.

For the sake of this example, let’s pretend the subfolder containing your site is named dist.

Step 1

Remove the dist directory from the project’s .gitignore file (it’s ignored by default by Yeoman).

	# lib/tasks/db.rake
	namespace :db do

	desc "Dumps the database to db/APP_NAME.dump"
	task :dump => :environment do
	cmd = nil
	with_config do \|app, host, db, user\|
	cmd = "pg_dump --host #{host} --username #{user} --verbose --clean --no-owner --no-acl --format=c #{db} > #{Rails.root}/db/#{app}.dump"
	end
	puts cmd

	(function() {
	// Do not use this library. This is just a fun example to prove a
	// point.

	var Bloop = window.Bloop = {};

	var mountId = 0;
	function newMountId() {
	return mountId++;
	}

	cd my_rails_app_root_dir
	rm bin/*
	bundle exec rake rails:update:bin
	bundle binstubs rspec-core
	spring binstub --all

	test:
	override:
	- bundle exec rspec spec

	deployment:
	acceptance:
	branch: master
	commands:
	- ./script/heroku_deploy.sh <ACCEPTANCE_HEROKU_APP>:
	timeout: 300

	# You have your csv data and it looks like so... It's in a file named "my_data.csv" and we want to import it into a table named "my_things".

	"1", "Something", "0.50", "2013-05-05 10:00:00"
	"2", "Another thing", "1.50", "2013-06-05 10:30:00"

	# Now you want to import it, go to the command line and type:

	$ PGPASSWORD=PWHERE psql -h HOSTHERE -U USERHERE DBNAMEHERE -c "\copy my_things FROM 'my_data.csv' WITH CSV;"

	# Voila! It's impoted. Now if you want to wipe it out and import a fresh one, you would do this:

	// <summary>
	// Logging methods.
	// </summary>
	Log = {
	Dump: function (object)
	{
	if (object)
	{
	console.debug(object);
	}