toe_tag

Ruby's default exception handling is strictly based on module and class inheritance. toe_tag provides additional utilities for creating your own exception groups, narrowing exceptions based on message, and executing arbitrary blocks to determine whether an exception should be caught -- all within the familiar rescue syntax.

Usage

require 'toe_tag'

# Exception grouping:
# Note that not all of the constants have to be defined. Missing ones will be ignored.
DatabaseError = ToeTag.category %w[ActiveRecord::JDBCError PG::Error ActiveRecord::StatementInvalid]

begin
  leaky_database_call
rescue DatabaseError => err
  # err could be any of the listed classes
end

# Filtering by message:
SpuriousError = DatabaseError.with_message(/spurious|pointless|meaningless/)

begin
  boring_database_call # ! raises PG::Error, "something spurious happened"
rescue SpuriousError
  log "something spurious happened, ignore it"
rescue DatabaseError
  log "watch out, something bad happened"
end

# Filtering by proc
class FancyError
  attr_reader :error_code

  def initialize(message, error_code)
    super message
    @error_code = error_code
  end
end

FancierError = FancyError.with_proc{|e| e.error_code == 123 }

begin
  fancy_api_call
rescue FancierError
  log "it's one of those 123 errors again"
rescue FancyError
  log "some unknown error, reraising"
  raise
end

Installation

Add this line to your application's Gemfile:

gem 'toe_tag'

And then execute:

$ bundle

Or install it yourself as:

$ gem install toe_tag

Contributing

1. Fork it.
2. Create your feature branch (git checkout -b my-new-feature).
3. Commit your changes (git commit -am 'Add some feature').
4. Push to the branch (git push origin my-new-feature).
5. Submit a pull request.