Wendbaar.nl » Development

Building a 3D printer

berl — Thu, 13 Oct 2011 20:55:51 +0000

Now the building has commenced!

I posted a live stream on the the frontpage:

(Click on the image)

Hacking on vacation

berl — Wed, 16 Feb 2011 06:42:51 +0000

I’m on vacation in New Zealand, visiting my sister (Marie-Louise a.k.a. Seven). Se happens to be engaged to a fellow Geek (Let’s call him Uan). Well, She’s more geek than us because she created the most complicated machine in the world (which we can’t even imagine to produce): a baby!

As an IT shop owner (http://queenstownhq.co.nz/) who’s always busy to satisfy his customers Uan tends to shift his “want to do projects” (because customers pay the bill right?) to the next weekend.

Because he already has a lot of the parts and of course there is a shed (all New Zealanders appear to have an shed. great inventions are made here: The world first JET powered beercooler), I offered some help. (otherwise I would ending up changing the new toddler’s diapers…..)

May I present to you: my

TODO list

DIY Touchscreen (we’re half way, more to come soon!)
Arduino hacks with Processing and OSC (I’ve got an Git Repository on Github)
- An philips Moodlight imitiation: PhilipsLed
You might think: “Dude, you’re on a bloody vacation! Go see the country!”. Yup, been there, done that! This vacation is for me to sit back and relax: I have been far too busy the last few months with working for clients. Now it’s some Leon time: do some personal interesting stuff!

I’ll keep you posted!

Automagically tagging releases in github

berl — Tue, 27 Apr 2010 17:24:46 +0000

(update: now available as a gem for capistrano)

Today at work we were discussing branching and tagging etc. to keep track of the currently deployed release on various servers. We’re working with Capistrano to do deploys.

This is a script I came up with:

Edit: refactored some errors out of it

Ralf: S3 logfile downloader and merger

berl — Wed, 10 Feb 2010 18:47:56 +0000

Today we released a new gem called Ralf, it stands for Retreive Amazon LogFiles

Download the gem at http://gemcutter.org/gems/ralf or browse the source at http://github.com/kjwierenga/ralf

Usage

Prerequirements:

An S3 account (duh)
Enable logging on S3 (use cyberduck for example)

Execution:

r = Ralf.new(:config => '/my/config.yaml', :date => '2010-02-01')
r.run

Or run it in one go:

Ralf.run(:config => '/my/config.yaml', :date => '2010-02-01')

Parameters:

:config   a YAML config file, if none given it tries to open /etc/ralf.yaml or ~/.ralf.yaml
:date     the date to parse

:aws_access_key_id      (required in config)
:aws_secret_access_key  (required in config)
:out_path               (required in config)
:out_prefix             (optional, defaults to 's3_combined') Prefix the output file

You can ommit a configuration file when you supply the required parameters :aws_access_key_id_, :aws_secret_access_key and :out_path
They take precedence over the config file

Caveats

There is no logrotation as we know it like on regular unix machines

More info: S3 Server Access Logging

TODO

CLI executable

Grouping/combinig on week/month

Credits:

This plugin is created for kerkdienstgemist.nl for processing the logfiles generated by S3.

Authors: Leon Berenschot and K.J. Wierenga

Sending prawn documents with ActionMailer

berl — Thu, 17 Dec 2009 08:32:18 +0000

Problem: How to send a prawn pdf wich normally is generated by a controller.

and keeping it DRY

Required: Prawn & prawnto

first: Make your prawnto settings global with an initializer

^?Download prawnto_globals.rb

PRAWN_DEFAULT_STYLES = {
  :page_size   => 'A4',
  :inline      => true,
  :left_margin => 50
}

second: create a ActionMailer

./script/generate mailer recipient_mailer invoice

third: edit the generated recipient mailer (note: because I’m using the views from the controller I’ve removed the autogenerated invoice.erb. Otherwise these will be included as well)

^?Download recipient_mailer.rb

# Include (optional) controller helpers
class Prawn::Document
  include PdfHelper
end
 
class RecipientMailer < ActionMailer::Base
  # explicitly require prawn, so we get all the goodieness
  require 'prawn'
  require "prawn/format"
  require "prawn/layout"
 
  def invoice(ledger_item)
    subject    "The subject"
    recipients '"Name" '
    from       '"Name" '
    sent_on    Time.now
    content_type    "multipart/mixed"
 
    # the templates live in RAILSROOT/app/views/documents
    # these are views normally generated by the DocumentsController
    part(:content_type => "multipart/alternative") do |alternative|
      alternative.part "text/plain" do |p|
        p.body = render_message("documents/show.txt", :ledger_item => ledger_item)
      end
 
      alternative.part "text/html" do |p|
        p.body = render_message("documents/show.html", :ledger_item => ledger_item)
      end
    end
 
    # And here is the magic:
    # probably could be refactored, but it's working!
    attachment "application/pdf" do |a|
      a.filename = "#{ledger_item.period}.pdf"
 
      template = File.open(File.join(Rails.root, 'app', 'views', 'documents', 'show.pdf.prawn')).read
 
      pdf = Prawn::Document.new(PRAWN_DEFAULT_STYLES);
      pdf.instance_eval do
        @ledger_item = ledger_item
        eval(template)
      end
 
      a.body = pdf.render
    end
 
  end
end

RER2009 Rumble

berl — Sun, 08 Nov 2009 11:55:20 +0000

We (@kjw and @leipeleon) participated in the RubyEnRails Rumble last weekend. It was a blast!

Using github on the mac for non-programmers

berl — Mon, 22 Jun 2009 13:30:20 +0000

A quick and dirty tutorial for some friends of mine.

Needed software:

git-osx-installer: Full native OSX git client.

Nice to have:

Textmate: text editor.
GitHub account (for push rights).
GitX: Grapichal tool for commiting to local repo (OSX 10.5+).

Create account on github

Go to http://github.com for an account.

Optional: Provide an SSH key for pushing changes.

Clone a Repo

My advice is to generate a special dir for the projects (mine is Rails).

Fire up the terminal and type:

^?View Code SHELL

    # Goto the dir
cd ~/Rails
    # if the repo is read only:
git clone git://github.com/LeipeLeon/facebooker.git
    # if you have push rights:
git clone git@github.com:LeipeLeon/facebooker.git
    # if you installed GitX (as mentioned above)
gitx

Adding changes

With the gitx program it’s easy to commit thanges to your local repo. When these are ready to commit to the master you sync it first with the HEAD and then push your changes.

^?View Code SHELL

    # get changes from the master repo to your local repo
git pull
    # push your changes
git push

Additional info:

If it’s a rails application you’re cloning, startup the server with

^?View Code SHELL

    # Copy database credentials, uses sqlite3 as default
cp config/database.yml.example config/database.yml
    # install required gems
rake gems:install
    # make tables
rake db:migrate
    # startup server at http://localhost:3000
script/server

and you will be able to use the application at http://localhost:3000

Burgerweeshuis Evenementen Kalender

berl — Wed, 13 May 2009 22:20:52 +0000

Bij het gebrek aan een RSS feed van de burgerweeshuis agenda heb ik zelf een (ruby) tooltje gebouwd om alle nieuwe evenementen in google calender te plaatsen.

Tevens wordt elk nieuw evenement automatisch geplaats in het twitter account @burgerweeshuis. Via @nuinhetbw alle evenementen een uur van te voren aangekondigd.

Get yours here:

Dit tooltje heeft de aandacht getrokken van diverse andere organisaties en ben dan ook van plan om hier iets meer mee te gaan doen. I’ll keep you posted!

Textmate Comments doesn’t work anymore!

berl — Wed, 04 Feb 2009 10:48:32 +0000

I like to stay on the edge of development so I’ve installed all the bundles available for TextMate in http://svn.textmate.org/trunk to my ~/Library/Application Support/TextMate.

But then you get a lot of bundles you don’t need like Active4D and ASP, so I disabled all the bundles who’s name didn’t ring a bell to me. The menu is readable again! Little did I know it was going to bite me in the foot the next day.

I performed this action late at night, just before getting some shut-eye. The next morning I was happily coding away until I discovered the Comment (command + /) feature didn’t work anymore!

Damn!

At first I thought it was a corrupted bundle, so I disabled all bundles to no avail. Then I reinstalled TextMate, nothing….

I have this plugin called Project+, updated it: nope, reinstall it: nope, disable it: nope.

With AppZapper I deleted the caches: no joy.

So I was already an hour away and I got frustrated….. So I enabled all plugins and Tada! IT WORKED AGAIN! By trail and error I found out:

It’s all in the bundle called “Source”.

Re-enabling this plugin restores all functionality! Whoohoo!!

So, here we go again, coding happily away…. ☯

Create a Facebook app with Rails

berl — Mon, 02 Feb 2009 10:57:53 +0000

In the beginning of this year I scored a programming gig for Wakoopa to spice up their Facebook app.

The original app was created in .NET by a third party and was buggy as hell. The goal was to recreate the app in Rails and have at least the same functionality.

Some befriended (PHP) developers warned me that facebook has some serious pitfalls so before I made an estimate for the project I bought a PDF called Developing Facebook Platform Applications with Rails from The Pragmatic Programmers and a PDF book from Peepcode.

Thanks to this PDF and the Facebooker plugin it was doable. I made the sample application as described in the PDF and so I had enough knowledge to create the WakoopaFacebook app. My advice: buy it!

Facebooker plugin

The data that has to be shown on the Facebook page comes from the Wakoopa API. This has to be converted to FBML markup to be compatible with Facebook. You also have the choice to work with iframes but FBML has some advanced features like automatic substitution of id’s to user names and userdetails.

A big plus also is that you don’t need to store all that data (it’s not permitted by facebook to store data longer than 24 hours), Facebook takes care of it. Also it takes the user’s privacy setting in consideration.

The Facebooker plugin provides a lot of things for you to make development a breeze. Session handling is automaticly provided by adding ensure_application_is_installed_by_facebook_user to the controller.

Facebook Caveats

The Facebook Wiki is a mess, so here are some tips that could save you some time. Also all requests from facebook are POST’s.

Session Keys

If the user hasn’t been to your application for a while (session timed out, 1 hour) or logged out (whichever comes first), the session_key becomes invalid. Costed me a few hours to find out, but you can get infinite session keys.

By asking the user for permission you can use offline_access, this will generate a infinite session key automaticly. (use

<%= fb_prompt_permission :offline_access, "May we publish on your feeds?" %>

to ask for access).

There is a difference between timelimited and infinite keys:

Infinite key:
   83d89fd715ac900df4783a68-741234111111
Temporary key with expiration:
   2.8dDnBR2FKc6yOeN2hHISRw__.86400.1232319600-741234111111

but I don’t know the exact scheme of this.

See Extended_permissions and Changes_to_Session_Keys for more details.

Updating the profile box/newsfeed

This can take a while (sometimes several seconds!) so make sure you don’t do that every request cycle. Put it in a separate process. Also publising to the newsfeed requires a session key, use the infinite session key to update the newsfeed if the user is not logged in.

Make your actions responsive

Facebook is very tight on timeouts, so if you’re not responsive enough the user will get a error message. Keep those controllers fast!

☯

Wendbaar.nl » Development

Building a 3D printer

Hacking on vacation

TODO list

Automagically tagging releases in github

Ralf: S3 logfile downloader and merger

Usage

Parameters:

Caveats

TODO CLI executable Grouping/combinig on week/month

Credits:

Sending prawn documents with ActionMailer

Problem: How to send a prawn pdf wich normally is generated by a controller.

RER2009 Rumble

Using github on the mac for non-programmers

Needed software:

Nice to have:

Create account on github

Clone a Repo

Adding changes

Additional info:

Burgerweeshuis Evenementen Kalender

Textmate Comments doesn’t work anymore!

Create a Facebook app with Rails

Facebooker plugin

Facebook Caveats

Session Keys

Updating the profile box/newsfeed

Make your actions responsive

TODO

CLI executable

Grouping/combinig on week/month