Michael Deimels Blog

My blog goes on

2020-11-17T00:00:00+00:00

My blog goes on

After this blog had a longer hibernation, I will try to write something more often.

One of my upcoming post will some insides from one of my private technical projects #covid-project.

Stay tuned…

Migrate a Rails Application from ruby 1.9.3 to ruby 2.2

2017-12-07T00:00:00+00:00

Migrate a Rails Application from ruby 1.9.3 to ruby 2.2

As first step to migrate all Rails 3 application to 5.1, we moved from ruby 1.9.3 to ruby 2.2.

Problems

YAML serializer was moved from Syck to Psych. There are some issues with utf-8 encodings.

script to migrate to Psych:

  require "ruby-progressbar"
  require "syck"

  def yaml_field_to_psych(model, field)
    id = model.id
    sql = "Select #{field} from #{model.class.table_name} where id = #{id}"
    result = ActiveRecord::Base.connection.execute(sql)

    yaml = result.first.first
    if yaml.present?
      syck_yaml = Syck.load(yaml)
      psych_yaml = Psych.dump(syck_yaml)
      ActiveRecord::Base.connection.execute("update #{model.class.table_name} set #{field}= #{ActiveRecord::Base.sanitize(psych_yaml)} where id = #{id}")
      true
    else
      false
    end
  rescue => e
    puts "Error: #{e} in #{model.class.name} field:#{field} id:#{id}"
  end

  puts "start fixing yaml fields"
  fixed = 0
  total = 0

  cnt = MyModel.count
  total += cnt
  progress_bar = ProgressBar.create(title: "fix MyModel", total: cnt, format: "%t %c/%C: |%B| %E")
  MyModel.find_each do |obj|
    fixed += 1 if yaml_field_to_psych(obj, :my_yaml_field)
    progress_bar.increment
  end

  puts "fixed:#{fixed}/#{total}"

iconv must be added to the Gemfile
test-unit must be added to the Gemfile
with ruby2.2 you get warnings when you have duplicate keys in a Hash

Improvments

the Application uses only have of the memory that leads to a overall performance

Make it OpenSource

2017-11-03T00:00:00+00:00

Make it OpenSource

this is a small checklist for open sourcing a project on Github

Steps

Make your github project public.
- go to the Settings page
Create a meaningfully README Here is a template
Choose a license.
- create a file called LICENSE
- choose a license type like the MIT License and put it there
- add your name and the date

Setup Travis

add the build info on top of your README

  [Status](https://travis-ci.org/YOURNAME/PROJECT.svg)](https://travis-ci.org/YOURNAME/PROJECT)

Codewars Katas

2017-10-24T00:00:00+00:00

Codewars Katas

Sometimes I challenge my self and try one of the code katas from coderwars. I’ll try to finish it within one pomodoro means 25 minutes. The setup on my local machine looks like this:

go to my katas dir and create a new folder
inside the folder, i create one lib and one spec folder
add a README.md with the link to the kata

# Two old ages

http://www.codewars.com/kata/two-oldest-ages-1/train/ruby

add a Gemfile:

source 'http://rubygems.org'

gem "guard-rspec"

then init the project

bundle install
guard init

create a function class under lib/

class TwoOldAges
  def self.call(numbers)
    Array(numbers).sort.last(2)
  end
end

and spec inside spec/

require_relative '../lib/two_old_ages'

RSpec.describe "TwoOldAges" do

  it "test something" do
    expect(TwoOldAges.call([1,5])).to eq([1,5])
  end

  ....
end

start Guard with bundle exec guard

Hapy Hacking!!!

Github Flavored Markdown

2014-11-28T00:00:00+00:00

Github Flavored Markdown

28. November 2014 - Wartenberg

config

before you can use the update github-flavored-markdown you must update _config.yml with:

markdown: redcarpet
redcarpet:
  extensions: ["no_intra_emphasis",
               "fenced_code_blocks",
               "autolink",
               "tables",
               "highlight",
               "with_toc_data",
               "strikethrough"]

Syntax

auto link

http://example.com

highlighted

This is ==highlighted==

This is ==highlighted==

Syntax highlighted

ruby

require 'redcarpet'
markdown = Redcarpet.new("Hello World!")
puts markdown.to_html

sql

SELECT * FROM mytable WHERE 1=2;

Strikethrough

this is ~~good~~ bad

this is ~~good~~ bad

**Everyone _must_ attend the meeting at 5 o'clock today.**

Everyone must attend the meeting at 5 o’clock today.

more info about GitHub Markdown

Markdown

Create a blog post

2014-11-27T00:00:00+00:00

Create a blog post

27. November 2014 - Wartenberg

create a new file under _posts format: YYYY-MM-DD-my-title.md
add a header in this new file like:

---
layout: post
title: My Title
---

add content with Markdown
start preview server bundle exec jekyll serve –watch
open http://0.0.0.0:4000/
deploy

git commit "my new blog post"
git push origin master"

Blog Setup

2012-03-01T00:00:00+00:00

Blog Setup

01 März 2012 - Wartenberg

Nach dem ich schon länger nach einer einfachen Lösung für’s bloggen gesucht habe, bin ich zufällig auf die Kombination von Github-Pages und Jekyll gestoßen.

Hier beschreibe ich nun wie ich die erste Version meiner Seite zum Laufen gebracht habe.

Github Page eirichten

ein Gihub Repository mit Username.github.com anlegen. In meinen Fall stereosupersonic.github.com
das Projekt lokal erstellen


    mkdir stereosupersonic.github.com  
    cd stereosupersonic.github.com 
    git init
    touch index.html
    git add index.html   
    git commit -m 'hompage init' 
    git remote add origin git@github.com:stereosupersonic/stereosupersonic.github.com.git
    git push origin master

unter http://stereosupersonic.github.com sollte man einen leere Seite sehen

##Domäne anpassen

eine Datei Namens CNAME anlegen und die Domäne eintragen deimel.de
nach github Pushen
beim Hoster oder DNS-Provider den DNS A record auf stereosupersonic.github.com zeigen lassen

##Jekyll einrichten

gem install jekyll
die Verzeichnisse “_layouts”, “_posts”, css und images anlegen
habe mich hier https://github.com/mojombo/mojombo.github.com inspirieren lassen ;-)
Pushen

##ersten Blog Post schreiben

im Verzeichnis “_posts” einen neu Datei anlegen im Muster Jahr-Monat-Tag-titel-ohne-leerzeichen.md
im Header layout: post und title: Mein erster Post eintragen
mit Markdown den gewünschten Text formatieren
Pushen

Erster Blog-Eintrag ist online.

Probleme

wenn beim Start der Fehler kommt invalid byte sequence in US-ASCII in der Bash folgende Variablen setzen:
export LANG=de_DE.UTF-8
export LC_ALL=de_DE.UTF-8

TODO

atom.xml für rss
rss bei Feedburner eintragen
Template Engine auf Haml umstellen
Layout auf Twitter-Bootstrap umstellen