Class: Google::Gax::PathTemplate

Inherits:
Object
  • Object
show all
Defined in:
lib/google/gax/path_template.rb

Overview

PathTemplate parses and format resource names

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ PathTemplate

Returns a new instance of PathTemplate.



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# File 'lib/google/gax/path_template.rb', line 133

def initialize(data)
  parser = PathParse.new(PathLex.new)
  @segments = parser.parse(data)
  @size = parser.segment_count
end

Instance Attribute Details

#segments ⇒ Object (readonly)

Returns the value of attribute segments.



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# File 'lib/google/gax/path_template.rb', line 131

def segments
  @segments
end

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/google/gax/path_template.rb', line 131

def size
  @size
end

Class Method Details

.format_segments(*segments) ⇒ String

Formats segments as a string.

Parameters:

  • The (Array<Segments>) —

    segments to be formatted

Returns:

  • (String) —

    the formatted output



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# File 'lib/google/gax/path_template.rb', line 144

def self.format_segments(*segments)
  template = ''
  slash = true
  segments.each do |segment|
    if segment.kind == TERMINAL
      template += '/' if slash
      template += segment.literal.to_s
      next
    end
    slash = true
    if segment.kind == BINDING
      template += "/{#{segment.literal}="
      slash = false
    else
      template += "#{segment.literal}}"
    end
  end
  template[1, template.length] # exclude the initial slash
end

Instance Method Details

#match(path) ⇒ Hash

Matches a fully qualified path template string.

Parameters:

  • path (String) —

    A fully qualified path template string.

Returns:

  • (Hash) —

    Var names to matched binding values.

Raises:

  • (ArgumentError) —

    If path can’t be matched to the template.



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# File 'lib/google/gax/path_template.rb', line 199

def match(path)
  that = path.split('/')
  current_var = nil
  bindings = {}
  segment_count = @size
  i = 0
  @segments.each do |segment|
    break if i >= that.size
    if segment.kind == TERMINAL
      if segment.literal == '*'
        bindings[current_var] = that[i]
        i += 1
      elsif segment.literal == '**'
        size = that.size - segment_count + 1
        segment_count += size - 1
        bindings[current_var] = that[i, size].join('/')
        i += size
      elsif segment.literal != that[i]
        throw ArgumentError.new(
          "mismatched literal: '#{segment.literal}' != '#{that[i]}'"
        )
      else
        i += 1
      end
    elsif segment.kind == BINDING
      current_var = segment.literal
    end
  end
  if i != that.size || i != segment_count
    throw ArgumentError.new(
      "match error: could not instantiate a path template from #{path}"
    )
  end
  bindings
end

#render(**bindings) ⇒ String

Renders a path template using the provided bindings.

Parameters:

  • binding (Hash) —

    A mapping of var names to binding strings.

Returns:

  • (String) —

    A rendered representation of this path template.

Raises:

  • (ArgumentError) —

    If a key isn’t provided or if a sub-template can’t be parsed.



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# File 'lib/google/gax/path_template.rb', line 170

def render(**bindings)
  out = []
  binding = false
  @segments.each do |segment|
    if segment.kind == BINDING
      literal_sym = segment.literal.to_sym
      unless bindings.key?(literal_sym)
        msg = "Value for key #{segment.literal} is not provided"
        raise ArgumentError.new(msg)
      end
      out.concat(PathTemplate.new(bindings[literal_sym]).segments)
      binding = true
    elsif segment.kind == END_BINDING
      binding = false
    else
      next if binding
      out << segment
    end
  end
  path = self.class.format_segments(*out)
  match(path)
  path
end

#to_s ⇒ Object 



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# File 'lib/google/gax/path_template.rb', line 235

def to_s
  self.class.format_segments(*@segments)
end