`module URL`

Helpers for working with URLs.

Definitions

`def self.escape(string, encoding = string.encoding)`

Escapes a string using percent encoding, e.g. a b -> a%20b.

Signature

parameter　string　String: The string to escape.
returns　String: The escaped string.

Implementation

def self.escape(string, encoding = string.encoding)
	string.b.gsub(/([^a-zA-Z0-9_.\-]+)/) do |m|
		"%" + m.unpack("H2" * m.bytesize).join("%").upcase
	end.force_encoding(encoding)
end

`def self.unescape(string, encoding = string.encoding)`

Unescapes a percent encoded string, e.g. a%20b -> a b.

Signature

parameter　string　String: The string to unescape.
returns　String: The unescaped string.

Implementation

def self.unescape(string, encoding = string.encoding)
	string.b.gsub(/%(\h\h)/) do |hex|
		Integer($1, 16).chr
	end.force_encoding(encoding)
end

`NON_PATH_CHARACTER_PATTERN = /([^a-zA-Z0-9_\-\.~!$&'()*+,;=:@\/]+)/.freeze`

Matches characters that are not allowed in a URI path segment. According to RFC 3986 Section 3.3 (https://tools.ietf.org/html/rfc3986#section-3.3), a valid path segment consists of "pchar" characters. This pattern identifies characters that must be percent-encoded when included in a URI path segment.

`def self.escape_path(path)`

Escapes non-path characters using percent encoding. In other words, this method escapes characters that are not allowed in a URI path segment. According to RFC 3986 Section 3.3 (https://tools.ietf.org/html/rfc3986#section-3.3), a valid path segment consists of "pchar" characters. This method percent-encodes characters that are not "pchar" characters.

Signature

parameter　path　String: The path to escape.
returns　String: The escaped path.

Implementation

def self.escape_path(path)
	encoding = path.encoding
	path.b.gsub(NON_PATH_CHARACTER_PATTERN) do |m|
		"%" + m.unpack("H2" * m.bytesize).join("%").upcase
	end.force_encoding(encoding)
end

`def self.encode(value, prefix = nil)`

Encodes a hash or array into a query string. This method is used to encode query parameters in a URL. For example, {"a" => 1, "b" => 2} is encoded as a=1&b=2.

Signature

parameter　value　Hash | Array | Nil: The value to encode.
parameter　prefix　String: The prefix to use for keys.

Implementation

def self.encode(value, prefix = nil)
	case value
	when Array
		return value.map {|v|
			self.encode(v, "#{prefix}[]")
		}.join("&")
	when Hash
		return value.map {|k, v|
			self.encode(v, prefix ? "#{prefix}[#{escape(k.to_s)}]" : escape(k.to_s))
		}.reject(&:empty?).join("&")
	when nil
		return prefix
	else
		raise ArgumentError, "value must be a Hash" if prefix.nil?
		
		return "#{prefix}=#{escape(value.to_s)}"
	end
end

`def self.scan(string)`

Scan a string for URL-encoded key/value pairs.

Signature

yields　{|key, value| ...}

parameter　key　String: The unescaped key.
parameter　value　String: The unescaped key.

Implementation

def self.scan(string)
	string.split("&") do |assignment|
		next if assignment.empty?
		
		key, value = assignment.split("=", 2)
		
		yield unescape(key), value.nil? ? value : unescape(value)
	end
end

`def self.split(name)`

Split a key into parts, e.g. a[b][c] -> ["a", "b", "c"].

Signature

parameter　name　String: The key to split.
returns　Array(String): The parts of the key.

Implementation

def self.split(name)
	name.scan(/([^\[]+)|(?:\[(.*?)\])/)&.tap do |parts|
		parts.flatten!
		parts.compact!
	end
end

`def self.assign(keys, value, parent)`

Assign a value to a nested hash.

Signature

parameter　keys　Array(String): The parts of the key.
parameter　value　Object: The value to assign.
parameter　parent　Hash: The parent hash.

Implementation

def self.assign(keys, value, parent)
	top, *middle = keys
	
	middle.each_with_index do |key, index|
		if key.nil? or key.empty?
			parent = (parent[top] ||= Array.new)
			top = parent.size
			
			if nested = middle[index+1] and last = parent.last
				top -= 1 unless last.include?(nested)
			end
		else
			parent = (parent[top] ||= Hash.new)
			top = key
		end
	end
	
	parent[top] = value
end

`def self.decode(string, maximum = 8, symbolize_keys: false)`

Decode a URL-encoded query string into a hash.

Signature

parameter　string　String: The query string to decode.
parameter　maximum　Integer: The maximum number of keys in a path.
parameter　symbolize_keys　Boolean: Whether to symbolize keys.
returns　Hash: The decoded query string.

Implementation

def self.decode(string, maximum = 8, symbolize_keys: false)
	parameters = {}
	
	self.scan(string) do |name, value|
		keys = self.split(name)
		
		if keys.empty?
			raise ArgumentError, "Invalid key path: #{name.inspect}!"
		end
		
		if keys.size > maximum
			raise ArgumentError, "Key length exceeded limit!"
		end
		
		if symbolize_keys
			keys.collect!{|key| key.empty? ? nil : key.to_sym}
		end
		
		self.assign(keys, value, parameters)
	end
	
	return parameters
end