This is a simple gem for Ruby on Rails that makes file names of paperclip attachments URL’s browser friendly by stripping any strange characters.

It attempts to do following operations on file name:

• transliterate string by using iconv standard transliteration functions,

• change string’s case to downcase,

• remove apostrophes and quotes,

• replace any non-letter or non-number character with a space,

• remove spaces from beginning and end of string,

• replace groups of spaces with single hyphen.

If result is an empty string, it computes MD5 hash of the original string.

It also adds new method String#strip_strange_characters so you can use stripping feature in any other context. It takes two boolean arguments:

• ignore - indicates if characters that cannot be transliterated should be ignored,

• hash - indicates if MD5 hash should be computed in case of empty result.

Here comes a quick code sample. Currently no docs.

class Person < ActiveRecord::Base
  has_attached_file :photo
  before_post_process :strip_strange_characters_from_attachments
end

It is enough to call this callback once as it affects all attachments of the model. Currently there’s no way to define callback for selected attachments.

1.9.3-p194 :001 > "ąqwertÓŁ".strip_strange_characters
 => "qwert" 
1.9.3-p194 :002 > "it's coffee time".strip_strange_characters
 => "its-coffee-time" 
1.9.3-p194 :003 > "ABCD_EFGH".strip_strange_characters
 => "abcd-efgh" 
1.9.3-p194 :004 > "///".strip_strange_characters
 => "884a6325c5f164f3cc6d5f97bd3e3231"

Code was tested with ruby-1.9.3-p194 [ amd64 ] under RVM.

The gems are hosted at Rubygems.org. Make sure you’re using the latest version of rubygems:

$ gem update --system

Then you can install the gem as follows:

$ gem install paperclip-strip-strange-characters

Add to your Gemfile:

gem "paperclip-strip-strange-characters", "~> 0.0.1"

and then type:

bundle install

The source code is available at github.com/saepia/paperclip-strip-strange-characters. You can either clone the git repository or download a tarball or zip file. Once you have the source, you can unpack it and use from wherever you downloaded.

• Initial release