Module: Contracts::FailureCallback

Included in:
Contract
Defined in:
lib/contracts/contract/failure_callback.rb

Constant Summary collapse

DEFAULT_FAILURE_CALLBACK =

Default implementation of failure_callback. Provided as a block to be able to monkey patch #failure_callback only temporary and then switch it back. First important usage - for specs.

proc do |data|
  msg = Contracts::ErrorFormatters.failure_msg(data)

  # this failed on the return contract
  raise ReturnContractError.new(msg, data) if data[:return_value]

  # this failed for a param contract
  raise data[:contracts].failure_exception.new(msg, data)
end

Instance Method Summary collapse

Instance Method Details

#failure_callback(data, use_pattern_matching = true) ⇒ Object

Callback for when a contract fails. By default it raises an error and prints detailed info about the contract that failed. You can also monkeypatch this callback to do whatever you want…log the error, send you an email, print an error message, etc.

Example of monkeypatching:

def Contract.failure_callback(data)
  puts "You had an error!"
  puts failure_msg(data)
  exit
end



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# File 'lib/contracts/contract/failure_callback.rb', line 29

def failure_callback(data, use_pattern_matching = true)
  if data[:contracts].pattern_match? && use_pattern_matching
    return DEFAULT_FAILURE_CALLBACK.call(data)
  end

  fetch_failure_callback.call(data)
end

#fetch_failure_callback ⇒ Object 



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# File 'lib/contracts/contract/failure_callback.rb', line 57

def fetch_failure_callback
  @failure_callback ||= DEFAULT_FAILURE_CALLBACK
end

#override_failure_callback(&blk) ⇒ Object

Used to override failure_callback without monkeypatching.

Takes: block parameter, that should accept one argument - data.

Example usage:

Contract.override_failure_callback do |data|
  puts "You had an error"
  puts failure_msg(data)
  exit
end



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# File 'lib/contracts/contract/failure_callback.rb', line 48

def override_failure_callback(&blk)
  @failure_callback = blk
end

#restore_failure_callback ⇒ Object

Used to restore default failure callback



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# File 'lib/contracts/contract/failure_callback.rb', line 53

def restore_failure_callback
  @failure_callback = DEFAULT_FAILURE_CALLBACK
end