Ruby compare sort en nonzero?

Just reminder for myself…
The method Numeric#nonzero?
returns self if the number is != 0 else it returns nil

Makes this code possible:

  objects.sort do |a, b|
    (a.lastname <=> b.lastname).nonzero? || (a.firstname <=> b.firstname)

Incompatible Rails Local Configuration

Today I experienced a problem when upgrading to rails 4.2 from rails 3.

When updating an Activerecord object with a DateTime value, I’ve got the following error:

NoMethodError: undefined method `getlocal' for Mon, 01 Jan -4712 00:00:00 +0000:DateTime

I had the following configuration in my Application object:

  config.active_record.default_timezone = :local  # store all values in the local time-zone 
  config.active_record.time_zone_aware_attributes = false # ignore the time zone

I don’t want time-zone information for this project.
But getting an error isn’t nice so I solved it by enabling the time_zone_aware_attributes.

  config.active_record.default_timezone = :local  # store all values in the local time-zone 
  config.active_record.time_zone_aware_attributes = true # ignore the time zone

rsync output compressor

Rsync is a very nice tool for automating remote backups. (Specially in combination with daily snapshots (like zfs snapshot) ).
Like many others I have automated the process of running rsync on a daily basis via a cron job. Cron nicely sends me an email with the output of the rsync command.

I usually use the -v option so I can see what files have been changed. This worked nicely several years ago when I didn’t have much changes on my server. But nowadays I often receive e-mails of 10 MB or larger. That’s not very useful.

Removing the -v option is an option, but I don’t see anything anymore (perhaps a total summary).

To solve this problem I’ve hacked together an rsync-output-compressor script :)
You can find it on

This scripts summarizes the output of rsync -v based on a given rules file. You can specify what files/folders should be explicitly mentioned and what folders/files should be grouped together.

This little script is written for ruby 1.9 and higher.

An example

For example let’s view the following output: (… = many more lines)

rsync -avz --delete /backups/remote_data
receiving incremental file list

Using the following filter: (compress-rules.txt)


results in the following output:

rsync -avz --delete /backups/remote_data | rsync-output-compressor.rb --rules compress-rules.txt
receiving incremental file list
   123    -5 /home/emma/public_html/
    40       /home/sarah/public_html/
     1       /home/david/private/special_file.txt
     2       /home/david/public_html/

The column with positive values are changed/added files and the column with negative values are the number of deleted files.

The tool has several other options like storing the original full output to an external location (option -f).

Using this script my daily emails have been reduced from 10MB to 30KB :)
And I still know what is happening with my backup.

Feel free to use and improve this little script!


Ruby undocument File.basename trick

Just stumbled upon the following trick to get the basename without an extension in Ruby:
(I didn’t know you could use “.*” to remove any extension).

File.basename( "filename/sample-filename.html", ".*" )
=> "sample-filename"

Fix rails database collations

Today I discovered my Ruby on Rails development environment database migrated with the wrong character encoding. It was using the MySQL default encoding latin1.
I didn’t feel throwing my database away because it contains a lot of stuff.

I used the following snippet to convert all columns to utf8

    ActiveRecord::Base.connection.tables.each do |table|
      ActiveRecord::Base.connection.execute( &quot;ALTER TABLE `#{table}` CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci&quot;)