lib/restclient/utils.rb
require 'http/accept'
module RestClient
# Various utility methods
module Utils
# Return encoding from an HTTP header hash.
#
# We use the RFC 7231 specification and do not impose a default encoding on
# text. This differs from the older RFC 2616 behavior, which specifies
# using ISO-8859-1 for text/* content types without a charset.
#
# Strings will use the default encoding when this method returns nil. This
# default is likely to be UTF-8 for Ruby >= 2.0
#
# @param headers [Hash<Symbol,String>]
#
# @return [String, nil] Return the string encoding or nil if no header is
# found.
#
# @example
# >> get_encoding_from_headers({:content_type => 'text/plain; charset=UTF-8'})
# => "UTF-8"
#
def self.get_encoding_from_headers(headers)
type_header = headers[:content_type]
return nil unless type_header
# TODO: remove this hack once we drop support for Ruby 2.0
if RUBY_VERSION.start_with?('2.0')
_content_type, params = deprecated_cgi_parse_header(type_header)
if params.include?('charset')
return params.fetch('charset').gsub(/(\A["']*)|(["']*\z)/, '')
end
else
begin
_content_type, params = cgi_parse_header(type_header)
rescue HTTP::Accept::ParseError
return nil
else
params['charset']
end
end
end
# Parse a Content-Type like header.
#
# Return the main content-type and a hash of params.
#
# @param [String] line
# @return [Array(String, Hash)]
#
def self.cgi_parse_header(line)
types = HTTP::Accept::MediaTypes.parse(line)
if types.empty?
raise HTTP::Accept::ParseError.new("Found no types in header line")
end
[types.first.mime_type, types.first.parameters]
end
# Parse semi-colon separated, potentially quoted header string iteratively.
#
# @private
#
# @deprecated This method is deprecated and only exists to support Ruby
# 2.0, which is not supported by HTTP::Accept.
#
# @todo remove this method when dropping support for Ruby 2.0
#
def self._cgi_parseparam(s)
return enum_for(__method__, s) unless block_given?
while s[0] == ';'
s = s[1..-1]
ends = s.index(';')
while ends && ends > 0 \
&& (s[0...ends].count('"') -
s[0...ends].scan('\"').count) % 2 != 0
ends = s.index(';', ends + 1)
end
if ends.nil?
ends = s.length
end
f = s[0...ends]
yield f.strip
s = s[ends..-1]
end
nil
end
# Parse a Content-Type like header.
#
# Return the main content-type and a hash of options.
#
# This method was ported directly from Python's cgi.parse_header(). It
# probably doesn't read or perform particularly well in ruby.
# https://github.com/python/cpython/blob/3.4/Lib/cgi.py#L301-L331
#
# @param [String] line
# @return [Array(String, Hash)]
#
# @deprecated This method is deprecated and only exists to support Ruby
# 2.0, which is not supported by HTTP::Accept.
#
# @todo remove this method when dropping support for Ruby 2.0
#
def self.deprecated_cgi_parse_header(line)
parts = _cgi_parseparam(';' + line)
key = parts.next
pdict = {}
begin
while (p = parts.next)
i = p.index('=')
if i
name = p[0...i].strip.downcase
value = p[i+1..-1].strip
if value.length >= 2 && value[0] == '"' && value[-1] == '"'
value = value[1...-1]
value = value.gsub('\\\\', '\\').gsub('\\"', '"')
end
pdict[name] = value
end
end
rescue StopIteration
end
[key, pdict]
end
# Serialize a ruby object into HTTP query string parameters.
#
# There is no standard for doing this, so we choose our own slightly
# idiosyncratic format. The output closely matches the format understood by
# Rails, Rack, and PHP.
#
# If you don't want handling of complex objects and only want to handle
# simple flat hashes, you may want to use `URI.encode_www_form` instead,
# which implements HTML5-compliant URL encoded form data.
#
# @param [Hash,ParamsArray] object The object to serialize
#
# @return [String] A string appropriate for use as an HTTP query string
#
# @see {flatten_params}
#
# @see URI.encode_www_form
#
# @see See also Object#to_query in ActiveSupport
# @see http://php.net/manual/en/function.http-build-query.php
# http_build_query in PHP
# @see See also Rack::Utils.build_nested_query in Rack
#
# Notable differences from the ActiveSupport implementation:
#
# - Empty hash and empty array are treated the same as nil instead of being
# omitted entirely from the output. Rather than disappearing, they will
# appear to be nil instead.
#
# It's most common to pass a Hash as the object to serialize, but you can
# also use a ParamsArray if you want to be able to pass the same key with
# multiple values and not use the rack/rails array convention.
#
# @since 2.0.0
#
# @example Simple hashes
# >> encode_query_string({foo: 123, bar: 456})
# => 'foo=123&bar=456'
#
# @example Simple arrays
# >> encode_query_string({foo: [1,2,3]})
# => 'foo[]=1&foo[]=2&foo[]=3'
#
# @example Nested hashes
# >> encode_query_string({outer: {foo: 123, bar: 456}})
# => 'outer[foo]=123&outer[bar]=456'
#
# @example Deeply nesting
# >> encode_query_string({coords: [{x: 1, y: 0}, {x: 2}, {x: 3}]})
# => 'coords[][x]=1&coords[][y]=0&coords[][x]=2&coords[][x]=3'
#
# @example Null and empty values
# >> encode_query_string({string: '', empty: nil, list: [], hash: {}})
# => 'string=&empty&list&hash'
#
# @example Nested nulls
# >> encode_query_string({foo: {string: '', empty: nil}})
# => 'foo[string]=&foo[empty]'
#
# @example Multiple fields with the same name using ParamsArray
# >> encode_query_string(RestClient::ParamsArray.new([[:foo, 1], [:foo, 2], [:foo, 3]]))
# => 'foo=1&foo=2&foo=3'
#
# @example Nested ParamsArray
# >> encode_query_string({foo: RestClient::ParamsArray.new([[:a, 1], [:a, 2]])})
# => 'foo[a]=1&foo[a]=2'
#
# >> encode_query_string(RestClient::ParamsArray.new([[:foo, {a: 1}], [:foo, {a: 2}]]))
# => 'foo[a]=1&foo[a]=2'
#
def self.encode_query_string(object)
flatten_params(object, true).map {|k, v| v.nil? ? k : "#{k}=#{v}" }.join('&')
end
# Transform deeply nested param containers into a flat array of [key,
# value] pairs.
#
# @example
# >> flatten_params({key1: {key2: 123}})
# => [["key1[key2]", 123]]
#
# @example
# >> flatten_params({key1: {key2: 123, arr: [1,2,3]}})
# => [["key1[key2]", 123], ["key1[arr][]", 1], ["key1[arr][]", 2], ["key1[arr][]", 3]]
#
# @param object [Hash, ParamsArray] The container to flatten
# @param uri_escape [Boolean] Whether to URI escape keys and values
# @param parent_key [String] Should not be passed (used for recursion)
#
def self.flatten_params(object, uri_escape=false, parent_key=nil)
unless object.is_a?(Hash) || object.is_a?(ParamsArray) ||
(parent_key && object.is_a?(Array))
raise ArgumentError.new('expected Hash or ParamsArray, got: ' + object.inspect)
end
# transform empty collections into nil, where possible
if object.empty? && parent_key
return [[parent_key, nil]]
end
# This is essentially .map(), but we need to do += for nested containers
object.reduce([]) { |result, item|
if object.is_a?(Array)
# item is already the value
k = nil
v = item
else
# item is a key, value pair
k, v = item
k = escape(k.to_s) if uri_escape
end
processed_key = parent_key ? "#{parent_key}[#{k}]" : k
case v
when Array, Hash, ParamsArray
result.concat flatten_params(v, uri_escape, processed_key)
else
v = escape(v.to_s) if uri_escape && v
result << [processed_key, v]
end
}
end
# Encode string for safe transport by URI or form encoding. This uses a CGI
# style escape, which transforms ` ` into `+` and various special
# characters into percent encoded forms.
#
# This calls URI.encode_www_form_component for the implementation. The only
# difference between this and CGI.escape is that it does not escape `*`.
# http://stackoverflow.com/questions/25085992/
#
# @see URI.encode_www_form_component
#
def self.escape(string)
URI.encode_www_form_component(string)
end
end
end