There is a conflict between current capistrano versions and the 2.5.1 net-ssh gem. Make sure you upgrade to 2.5.2, then it should work again.

Capistrano recently had some API changes that can results in deploys not working when running with old deploy.rb files.

So let's bundle it. Put capistrano into your Gemfile, like this:

# Gemfile

group :deploy do
  gem 'capistrano'
  gem 'capistrano_colors'
end

It's possible you need to do a bundle update net-ssh to get things running.

Now double check that all your custom hooks are actually still called. One candidate might be an after deploy:symlink hook that has been renamed into `after deploy:creat...

When requests arrive at the application servers simultaneously, weird things can happen. Sometimes, this can also happen if a user double-clicks on a button, for example.

This often leads to problems, as two object instances are modified in parallel maybe by different code and one of the requests writes the results to the database.

In case you want to make sure that only one of the requests "wins", i.e. one of the requests is fully executed and completed while the other one at least has to wait for the first request to be completed, you ha...

Slides presenting ways to integrate the ideas of Aspect-Oriented Programming in Ruby.

Outline

• Why Aspect-Oriented Programming?
• AOP in Java and AspectJ (a Review).
• AOP in Ruby.
  • What you can do today.
  • Example AOP-isms in Ruby on Rails.
• Aspect-Oriented Design.
• The AOP Promise for Tomorrow.

If you get an error like this ...

 can’t find executable rails for rails-3.2.3 (Gem::Exception)

... one of several things might be wrong.

1. You're using RVM

It's possible that you have a system-wide gem executable (like rails) that requires a gem that is not available in the current RVM Ruby or gemset. Check what Ruby you are using (rvm current) and look out for .rvmrc files in your current directory (which change your Ruby upon entering the directory).

2. You killed a gem install process
   ----------...

OCRA (One-Click Ruby Application) builds Windows executables from Ruby source code. The executable is a self-extracting, self-running executable that contains the Ruby interpreter, your source code and any additionally needed ruby libraries or DLL.

ocra [option] script.rb

Will package “script.rb“, the Ruby interpreter and all dependencies (gems and DLLs) into an executable named “script.exe“.

DTAUS & DTAZV are formats for German bank transfers and is short for "Datenträgeraustausch". The format itself totally sucks because it was established in the last century, to be used on floppy disks. Still almost all German banks use it (they only seem innovative at robbing), and it is therefore supported in common banking programs too.

This gem saves you all the trouble when generating DTAUS- or DTAZV-text.

In order to navigate through the browser history. you can manipulate the window.history object via javascript like follows:

When /^I go back in the browser history$/ do
  page.evaluate_script('window.history.back()')
end 

For further functions of the window and history objects check out this link.

An improved version of this step is now part of our gem spreewald on Github.

All our projects have enum-like requirements like this:

• An attribute value must be included in a given set of values.
• The list of allowed values must be retrievable in order to render <select> boxes.
• Each value has a humanized label.
• Sometimes there is a default value.

Most of the time, this requirement is also needed:

• The list of assignable values depends on the user who is currently signed in.

In our past projects there are many different solutions for these related requirements, e.g. ChoiceTrait, methods like `available_...

Controller responses often include Javascript code that contains values from Ruby variables. E.g. you want to call a Javascript function foo(...) with the argument stored in the Ruby variable @foo. You can do this by using ERB tags (<%= ruby_expression %>) or, in Haml, interpolation syntax (#{ruby_expression}).

In any case you will take care of proper quoting and escaping of quotes, line feeds, etc. A convenient way to do this is to use Object#json, which is defined for Ruby strings, numb...

This is for you if Passenger gives you the following useless error message.

Passenger encountered the following error:\
The application spawner server exited unexpectedly: Unexpected end-of-file detected.

Exception class:

PhusionPassenger::Rack::ApplicationSpawner::Error

Most often this happens because you are missing a gem. Usually Passenger would tell you about that but in some cases it can't.

To resolve this issue, run:

bundle install

If this does not do the trick for you, take a look at the Apache log files for de...

If you cannot install the gem 'RedCloth' via bundle install you might want to try the following.

Specifying extra build options for bundler which will only be applied when building RedCloth:

bundle config build.RedCloth --with-cflags=-w

Geordi, our collection of command line tools, has been extended by another command deploy-to-production. This script encapsulates the following workflow:

• Pull the production branch.
• Show which commits from the master would make it to production with this deploy.
• Ask if you want to proceed.
• If yes, merge the master into the production branch, push and deploy with bundle exec cap production deploy:migrations

The script will ask you for the names of your master branch, production branch an...

After installing Bundler 1.1 you will get the following warning when running tests:

WARNING: Cucumber-rails required outside of env.rb. The rest of loading is being defered until env.rb is called.\
To avoid this warning, move 'gem cucumber-rails' under only group :test in your Gemfile

The warning is misleading because it has nothing to do with moving cucumber-rails into a :test group. Instead you need to change your Gemfile to say:

gem 'cucumber-rails', :require => false

How to get a backtrace from a running Ruby process:

Ruby 2.6

# First, find out the PID of your Ruby process (e.g. passenger-status)
$ sudo gdb -p PID
(gdb) call rb_eval_string("$stderr.reopen('/tmp/ruby-debug.' + Process.pid.to_s); $stderr.sync = true") # redirects stderr
(gdb) call rb_backtrace() # prints current backtrace to /tmp/ruby-debug.xxx

Stop the process afterwards, since stderr is now borked.

It is possible you have to call rb_backtrace() multiple times to get the full stacktrace.

Previous method on Ruby 2....

TL;DR {} binds stronger than do … end (as always in Ruby, special characters bind stronger than words)

Demo

✔️ Right way

names = ['bRUce', 'STaN', 'JOlIE']

# Blocks in braces are passed to the rightmost method
print names.map { |name| name.downcase }
print(names.map do |name| name.downcase end) # equivalent
=> ["bruce", "stan", "jolie"]

❌ Wrong way

Avoid the examples below, as you pass at least one block to print and not to the enumerator.

names = ['bRUce', 'STaN', 'JOlIE'] 

# Blocks in do…end ar...

This card needs to be updated for Rails 3+.

Since there is no --debugger flag you need to run:

rdebug script/runner lib/scripts/something.rb

That will open an debugging IRB right away, like this:

require File.dirname(__FILE__) + '/../config/boot'
(rdb:1) _

Enter c to continue and reach your actual debugger call. Then, debug away.

If nothing happens for you: Make sure ruby-debug is available in the Gemfile and you require it.

The following two hints are taken from Github's Ruby style guide:

If your regular expression mentions a lot of forward slashes, you can use the alternative delimiters %r(...), %r[...] or %r{...} instead of /.../.

 %r(/blog/2011/(.*))
 %r{/blog/2011/(.*)}
 %r[/blog/2011/(.*)]

If your regular expression is growing complex, you can use the /x modifier to ignore whitespace and comments:

regexp = %r{
  start         # some text
  \s            # white space char
  (group)    ...

This will give you the string that appears most often in an array:

names = %w[ foo foo bar bar bar baz ]
names.group_by(&:to_s).values.max_by(&:size).try(:first)
=> "bar"

This is very similar to the linked StackOverflow thread, but does not break on empty arrays.

Note that try is provided by ActiveSupport (Rails). You could explicitly load activesupport or use andand on plain Ruby.

After you configured your ODBC describe in

• Fix [RubyODBC]Cannot allocate SQLHENV when connecting to MSSQL 2005 with Ruby 1.8.7. on Ubuntu 10.10
• and Connecting to MSSQL with Ruby on Ubuntu - lambie.org

you can connect with sequel:

require "rubygems"
require "se...

I followed this nice guide Connecting to MSSQL with Ruby on Ubuntu - lambie.org until I ran in the following errors:

irb(main):001:0> require "dbi"; dbh = DBI.connect('dbi:ODBC:MyLegacyServer', 'my_name', 'my_password')

DBI::DatabaseError: INTERN (0) [RubyODBC]Cannot allocate SQLHENV
  from /usr/lib/ruby/1.8/dbd/odbc/driver.rb:36:in `connect'
  from /usr/lib/ruby/1.8/dbi/handles/driver.rb:33:in `connect'
  from /usr/lib/ruby...

Nice article to educate your non-geek girlfriend/boyfriend about the joys of programming.