Class: Mustermann::Pattern Abstract

Inherits:
Object
  • Object
show all
Includes:
Mustermann
Defined in:
lib/mustermann/pattern.rb

Overview

This class is abstract.

Superclass for all pattern implementations.

Direct Known Subclasses

Composite, Identity, RegexpBased, Shell

Constant Summary collapse

PATTERN_METHODS =
%w[expand to_templates].map(&:to_sym)

Constants included from Mustermann

DEFAULT_TYPE, VERSION

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Mustermann

[]

Constructor Details

#initialize(string, **options) ⇒ Pattern

Returns a new instance of Pattern.

Parameters:

  • string (String)

    the string representation of the pattern

  • options (Hash) (defaults to: {})

    options for fine-tuning the pattern behavior

Raises:

  • (Mustermann::Error)

    if the pattern can't be generated from the string

See Also:


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# File 'lib/mustermann/pattern.rb', line 70

def initialize(string, options = {})
  uri_decode = options.fetch(:uri_decode, true)
  @uri_decode = uri_decode
  @string     = string.to_s.dup
end

Class Method Details

.new(string, **options) ⇒ Mustermann::Pattern

Returns a new instance of Mustermann::Pattern.

Parameters:

  • string (String)

    the string representation of the pattern

  • options (Hash) (defaults to: {})

    options for fine-tuning the pattern behavior

Returns:

Raises:

  • (ArgumentError)

    if some option is not supported

  • (Mustermann::Error)

    if the pattern can't be generated from the string

See Also:


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# File 'lib/mustermann/pattern.rb', line 50

def self.new(string, options = {})
  ignore_unknown_options = options.fetch(:ignore_unknown_options, false)
  options.delete(:ignore_unknown_options)
  unless ignore_unknown_options
    unsupported = options.keys.detect { |key| not supported?(key, options) }
    raise ArgumentError, "unsupported option %p for %p" % [unsupported, self] if unsupported
  end

  @map ||= EqualityMap.new
  @map.fetch(string, options) { super(string, options) }
end

.supported?(option, options = {}) ⇒ Boolean

Returns Whether or not option is supported.

Parameters:

  • option (Symbol)

    The option to check.

Returns:

  • (Boolean)

    Whether or not option is supported.


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# File 'lib/mustermann/pattern.rb', line 40

def self.supported?(option, options = {})
  supported_options.include? option
end

.supported_optionsArray<Symbol> .supported_options(*list) ⇒ Array<Symbol>

List of supported options.

Overloads:

  • .supported_optionsArray<Symbol>

    Returns list of supported options.

    Returns:

    • (Array<Symbol>)

      list of supported options

  • .supported_options(*list) ⇒ Array<Symbol>

    This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

    Adds options to the list.

    Parameters:

    • *list (Symbol)

      adds options to the list of supported options

    Returns:

    • (Array<Symbol>)

      list of supported options


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# File 'lib/mustermann/pattern.rb', line 24

def self.supported_options(*list)
  @supported_options ||= []
  options = @supported_options.concat(list)
  options += superclass.supported_options if self < Pattern
  options
end

Instance Method Details

#&(other) ⇒ Object


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# File 'lib/mustermann/pattern.rb', line 297

def &(other)
  Mustermann.new(self, other, :operator => :&, :type => :identity)
end

#===(string) ⇒ Boolean

Note:

Needs to be overridden by subclass.

Returns Whether or not the pattern matches the given string.

Parameters:

  • string (String)

    The string to match against

Returns:

  • (Boolean)

    Whether or not the pattern matches the given string

Raises:

  • (NotImplementedError)

See Also:


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# File 'lib/mustermann/pattern.rb', line 101

def ===(string)
  raise NotImplementedError, 'subclass responsibility'
end

#=~(string) ⇒ Integer?

Returns nil if pattern does not match the string, zero if it does.

Parameters:

  • string (String)

    The string to match against

Returns:

  • (Integer, nil)

    nil if pattern does not match the string, zero if it does.

See Also:


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# File 'lib/mustermann/pattern.rb', line 93

def =~(string)
  0 if self === string
end

#^(other) ⇒ Object


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# File 'lib/mustermann/pattern.rb', line 301

def ^(other)
  Mustermann.new(self, other, :operator => :^, :type => :identity)
end

#expand(behavior = nil, values = {}) ⇒ String

Note:

This method is only implemented by certain subclasses.

Expanding is supported by almost all patterns (notable execptions are Shell, Regular and Simple).

Union Composite patterns (with the | operator) support expanding if all patterns they are composed of also support it.

Examples:

Expanding a pattern

pattern = Mustermann.new('/:name(.:ext)?')
pattern.expand(name: 'hello')             # => "/hello"
pattern.expand(name: 'hello', ext: 'png') # => "/hello.png"

Checking if a pattern supports expanding

if pattern.respond_to? :expand
  pattern.expand(name: "foo")
else
  warn "does not support expanding"
end

Parameters:

  • behavior (Symbol) (defaults to: nil)

    What to do with additional key/value pairs not present in the values hash. Possible options: :raise, :ignore, :append.

  • values (Hash{Symbol: #to_s, Array<#to_s>}) (defaults to: {})

    Values to use for expansion.

Returns:

  • (String)

    expanded string

Raises:

  • (NotImplementedError)

    raised if expand is not supported.

  • (Mustermann::ExpandError)

    raised if a value is missing or unknown

See Also:


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# File 'lib/mustermann/pattern.rb', line 218

def expand(behavior = nil, values = {})
  raise NotImplementedError, "expanding not supported by #{self.class}"
end

#match(string) ⇒ MatchData, ...

Returns MatchData or similar object if the pattern matches.

Parameters:

  • string (String)

    The string to match against

Returns:

See Also:


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# File 'lib/mustermann/pattern.rb', line 86

def match(string)
  SimpleMatch.new(string) if self === string
end

#named_capturesHash{String: Array<Integer>}

Returns capture names mapped to capture index.

Returns:

  • (Hash{String: Array<Integer>})

    capture names mapped to capture index.

See Also:


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# File 'lib/mustermann/pattern.rb', line 167

def named_captures
  {}
end

#namesArray<String>

Returns capture names.

Returns:

  • (Array<String>)

    capture names.

See Also:


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# File 'lib/mustermann/pattern.rb', line 173

def names
  []
end

#params(string = nil, options = {}) ⇒ Hash{String: String, Array<String>}?

Returns Sinatra style params if pattern matches.

Parameters:

  • string (String) (defaults to: nil)

    the string to match against

Returns:

  • (Hash{String: String, Array<String>}, nil)

    Sinatra style params if pattern matches.


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# File 'lib/mustermann/pattern.rb', line 179

def params(string = nil, options = {})
  options, string = string, nil if string.is_a?(Hash)
  captures = options.fetch(:captures, nil)
  offset   = options.fetch(:offset, 0)
  return unless captures ||= match(string)
  params   = named_captures.map do |name, positions|
    values = positions.map { |pos| map_param(name, captures[pos + offset]) }.flatten
    values = values.first if values.size < 2 and not always_array? name
    [name, values]
  end

  Hash[params]
end

#peek(string) ⇒ String?

Tries to match the pattern against the beginning of the string (as opposed to the full string). Will return the substring if it matches.

Examples:

pattern = Mustermann.new('/:name')
pattern.peek("/Frank/Sinatra") # => "/Frank"

Parameters:

  • string (String)

    The string to match against

Returns:

  • (String, nil)

    matched subsctring


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# File 'lib/mustermann/pattern.rb', line 128

def peek(string)
  size = peek_size(string)
  string[0, size] if size
end

#peek_match(string) ⇒ MatchData, ...

Tries to match the pattern against the beginning of the string (as opposed to the full string). Will return a MatchData or similar instance for the matched substring.

Examples:

pattern = Mustermann.new('/:name')
pattern.peek("/Frank/Sinatra") # => #<MatchData "/Frank" name:"Frank">

Parameters:

  • string (String)

    The string to match against

Returns:

See Also:


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# File 'lib/mustermann/pattern.rb', line 143

def peek_match(string)
  matched = peek(string)
  match(matched) if matched
end

#peek_params(string) ⇒ Array<Hash, Integer>?

Tries to match the pattern against the beginning of the string (as opposed to the full string). Will return a two element Array with the params parsed from the substring as first entry and the length of the substring as second.

Examples:

pattern   = Mustermann.new('/:name')
params, _ = pattern.peek_params("/Frank/Sinatra")

puts "Hello, #{params['name']}!" # Hello, Frank!

Parameters:

  • string (String)

    The string to match against

Returns:

  • (Array<Hash, Integer>, nil)

    Array with params hash and length of substing if matched, nil otherwise


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# File 'lib/mustermann/pattern.rb', line 160

def peek_params(string)
  match = peek_match(string)
  [params(nil, :captures => match), match.to_s.size] if match
end

#peek_size(string) ⇒ Integer?

Tries to match the pattern against the beginning of the string (as opposed to the full string). Will return the count of the matching characters if it matches.

Examples:

pattern = Mustermann.new('/:name')
pattern.size("/Frank/Sinatra") # => 6

Parameters:

  • string (String)

    The string to match against

Returns:

  • (Integer, nil)

    the number of characters that match


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# File 'lib/mustermann/pattern.rb', line 114

def peek_size(string)
  # this is a very naive, unperformant implementation
  string.size.downto(0).detect { |s| self === string[0, s] }
end

#to_procProc

Returns proc wrapping #===.

Examples:

pattern = Mustermann.new('/:a/:b')
strings = ["foo/bar", "/foo/bar", "/foo/bar/"]
strings.detect(&pattern) # => "/foo/bar"

Returns:

  • (Proc)

    proc wrapping #===


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# File 'lib/mustermann/pattern.rb', line 311

def to_proc
  @to_proc ||= method(:===).to_proc
end

#to_sString

Returns the string representation of the pattern.

Returns:

  • (String)

    the string representation of the pattern


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# File 'lib/mustermann/pattern.rb', line 77

def to_s
  @string.dup
end

#to_templatesArray<String>

Note:

This method is only implemented by certain subclasses.

Generates a list of URI template strings representing the pattern.

Note that this transformation is lossy and the strings matching these templates might not match the pattern (and vice versa).

This comes in quite handy since URI templates are not made for pattern matching. That way you can easily use a more precise template syntax and have it automatically generate hypermedia links for you.

Template generation is supported by Sinatra, Rails, Template and Identity patterns. Union Composite patterns (with the | operator) support template generation if all patterns they are composed of also support it.

Examples:

generating templates

Mustermann.new("/:name").to_templates                   # => ["/{name}"]
Mustermann.new("/:foo(@:bar)?/*baz").to_templates       # => ["/{foo}@{bar}/{+baz}", "/{foo}/{+baz}"]
Mustermann.new("/{name}", type: :template).to_templates # => ["/{name}"]

generating templates from composite patterns

pattern  = Mustermann.new('/:name')
pattern |= Mustermann.new('/{name}', type: :template)
pattern |= Mustermann.new('/example/*nested')
pattern.to_templates # => ["/{name}", "/example/{+nested}"]

Checking if a pattern supports expanding

if pattern.respond_to? :to_templates
  pattern.to_templates
else
  warn "does not support template generation"
end

Returns:

  • (Array<String>)

    list of URI templates

Raises:

  • (NotImplementedError)

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# File 'lib/mustermann/pattern.rb', line 257

def to_templates
  raise NotImplementedError, "template generation not supported by #{self.class}"
end

#|(other) ⇒ Mustermann::Pattern #&(other) ⇒ Mustermann::Pattern #^(other) ⇒ Mustermann::Pattern

Returns a composite pattern.

Overloads:

  • #|(other) ⇒ Mustermann::Pattern

    Creates a pattern that matches any string matching either one of the patterns. If a string is supplied, it is treated as an identity pattern.

    Examples:

    pattern = Mustermann.new('/foo/:name') | Mustermann.new('/:first/:second')
    pattern === '/foo/bar' # => true
    pattern === '/fox/bar' # => true
    pattern === '/foo'     # => false
  • #&(other) ⇒ Mustermann::Pattern

    Creates a pattern that matches any string matching both of the patterns. If a string is supplied, it is treated as an identity pattern.

    Examples:

    pattern = Mustermann.new('/foo/:name') & Mustermann.new('/:first/:second')
    pattern === '/foo/bar' # => true
    pattern === '/fox/bar' # => false
    pattern === '/foo'     # => false
  • #^(other) ⇒ Mustermann::Pattern

    Creates a pattern that matches any string matching exactly one of the patterns. If a string is supplied, it is treated as an identity pattern.

    Examples:

    pattern = Mustermann.new('/foo/:name') ^ Mustermann.new('/:first/:second')
    pattern === '/foo/bar' # => false
    pattern === '/fox/bar' # => true
    pattern === '/foo'     # => false

Parameters:

Returns:


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# File 'lib/mustermann/pattern.rb', line 293

def |(other)
  Mustermann.new(self, other, :operator => :|, :type => :identity)
end