Use Memoizer instead of ActiveSupport::Memoizable

ActiveSupport::Memoizable will be removed from Rails and has a lot of strange caveats that will ruin your day.

Use the Memoizer gem Show archive.org snapshot instead. It works in all past and future Railses and has none of the annoying "features" of ActiveSupport::Memoizable. It just does memoization and does it well.

The syntax is similiar also:

class Foo
  include Memoizer
  
  def bar
      ...
  end
  
  memoize :bar
  
end

If you're using Ruby 2.1+, you can write this even shorter:

class Foo
  include Memoizer
  
  memoize def bar
      ...
  end

end

This is because def returns the method name as a symbol Show archive.org snapshot in 2.1+.

Henning Koch

makandra.com

Say thanks

Last edit

Over 7 years ago

Arne Hartherz

License

Source code in this card is licensed under the MIT License.

Use ActiveSupport autoloading outside of Rails

The following code activates autoloading using ActiveSupport 3.x:

require 'active_support'
require 'active_support/dependencies'
relative_load_paths = %w[app/controllers app/models]
ActiveSupport::Dependencies.autoload_paths += re...

Force SSH client to use password authentication instead of public key

To test if you can connect to a host using password authentication and explicitly deny public key authentication:

ssh -o PreferredAuthentications=password -o PubkeyAuthentication=no user@host

This also works for Secure Copy:

scp -o ...

Working on the Linux command line: Use the `tree` command instead of repeated `cd` and `ls`

The tree command will show you the contents of a directory and all it's sub directories as a tree:

>tree
.
├── a
│   ├── file_1.txt
│   └── file_2.txt
└── b
    ├── c
    │   └── even_more.txt
    └── more.txt

3 directories, 4 files

I...

Use CSS sibling selectors instead :last-child (or :first-child)

Often times you want to give a bunch of elements the same style, except for the last. For example borders or margins.

You probably commonly used the :last-child CSS meta selector like so:

.foo {
  border-bottom: 1px dashed #000;
}
.foo:las...

Get the initial username which you used to login to your Linux system

If you need the initial user which you used to login to your Linux system or the time when you login you can do:

whoami

One purpose of this could be the .bashrc to show different Bash Prompts for root to different users:

if [ $(whoa...

Posted by Henning Koch to makandra dev (2012-07-02 18:22)

Use Memoizer instead of ActiveSupport::Memoizable

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