Module: Brine::ParameterTransforming

Included in:
Brine, Selecting::Selector
Defined in:
lib/brine/transforming.rb

Overview

Convert provided paramters to richer types.

This eases use of types beyond the Cucumber-provided simple strings.

Defined Under Namespace

Classes: Transformer

Constant Summary collapse

DATE =

Constants used for DateTime transformation.

'\d{4}-\d{2}-\d{2}'
TIME = 
'\d{2}:\d{2}:\d{2}'
MILLIS = 
'(?:\.\d{3})?'
TZ = 
'(?:Z|(?:[+-]\d{2}:\d{2}))'

Instance Method Summary collapse

Instance Method Details

#expand(val, binding) ⇒ Object

Expand val if needed and transform the result.

If val is not ‘expand`able it will be returned as is.

Parameters:

  • val (Object) —

    Provide the value to potentially expand.

Returns:

  • (Object) —

    Return the value of val, expanding as appropriate.

[View source]

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# File 'lib/brine/transforming.rb', line 153

def expand(val, binding)
  if val.respond_to? :expand
    transformed_parameter(val.expand(binding))
  else
    val
  end
end

#parameter_transformers ⇒ Object

Expose the chain of Transformers which will be used to convert parameters.

In the default implicit mode the list will be iterated over in sequence and the first Transformer which can handle the input will be used. The order of the Transformers is therefore significant: higher priority or more specific Transfomers should be earlier in the list than those that are lower priority or can handle a superset of supported input relative to those previous.

This exposed for direct list manipulation as an advanced customization point.

[View source]

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# File 'lib/brine/transforming.rb', line 85

def parameter_transformers
  @parameter_transformers ||= [

    # These will be deprecated in preference for explicit type specification.
    Transformer.new('Double Quoted', /\A".*"\z/) {|input|
      input[1..-2] },
    Transformer.new('Single Quoted', /\A'.*'\z/) {|input|
      input[1..-2] },

    # Whitespace removal transforms
    # Handle stripping leading and trailing whitespace.
    # These are split out from the transforms to consolidate the behavior.
    # They call transform on the stripped value so that subsequent transforms no longer
    # have to deal with such whitespace.
    #
    # Note that these need to deal with multiline string arguments which require
    # the multiline flag and \A/\z anchors to properly operate on the full string rather than
    # being line oriented. The calls to +#strip+ are also not likely to properly clean up
    # multiline strings but is just meant as a (potentially ineffective) optimization over
    # recursive calls and capturing.
    Transformer.new('Trailing Whitespace', /\A\s+.*\z/) {|input|
      transformed_parameter(input.strip) },
    Transformer.new('Leading Whitespace', /\A.*\s+\z/m) {|input|
      transformed_parameter(input.strip) },

    # Template Expansion
    Transformer.new('Template', /.*{{.*}}.*/) {|input|
      as_template(input) },

    # Scalars
    Transformer.new('Integer', /\A-?\d+\z/) {|input|
      input.to_i },
    Transformer.new('Boolean', /\Atrue|false\z/) {|input|
      input.to_s == "true" },
    # This presently does not support flags after the closing slash, support for these should be added as needed
    Transformer.new('Regex', /\A\/.*\/\z/) {|input|
      Regexp.new(input[1..-2]) },
    Transformer.new('DateTime', /^#{DATE}T#{TIME}#{MILLIS}#{TZ}$/) {|input|
      Time.parse(input) },

    # Structures
    Transformer.new('Array', /\A\[.*\]\z/m) {|input| JSON.parse(input) },
    Transformer.new('Object', /\A{.*}\z$/m) {|input| JSON.parse(input) },

    # String sentinel...this is last to act as a catch-all.
    Transformer.new('String', /.*/) {|input| input },
  ]
end

#transformed_parameter(input) ⇒ Object

Transform the provided input using #parameter_transformers.

Parameters:

  • input (String) —

    Pass the String input as provided by Cucumber.

Returns:

  • (Object) —

    Return input as converted by the handling Transformer.

[View source]

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# File 'lib/brine/transforming.rb', line 140

def transformed_parameter(input)
  parameter_transformers.find {|it| it.can_handle? input }
    .transform(input)
end