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query_parser.rb
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query_parser.rb
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# frozen_string_literal: true
require 'uri'
module Rack
class QueryParser
DEFAULT_SEP = /[&] */n
COMMON_SEP = { ";" => /[;] */n, ";," => /[;,] */n, "&" => /[&] */n }
# ParameterTypeError is the error that is raised when incoming structural
# parameters (parsed by parse_nested_query) contain conflicting types.
class ParameterTypeError < TypeError; end
# InvalidParameterError is the error that is raised when incoming structural
# parameters (parsed by parse_nested_query) contain invalid format or byte
# sequence.
class InvalidParameterError < ArgumentError; end
# ParamsTooDeepError is the error that is raised when params are recursively
# nested over the specified limit.
class ParamsTooDeepError < RangeError; end
def self.make_default(_key_space_limit=(not_deprecated = true; nil), param_depth_limit)
unless not_deprecated
warn("`first argument `key_space limit` is deprecated and no longer has an effect. Please call with only one argument, which will be required in a future version of Rack", uplevel: 1)
end
new Params, param_depth_limit
end
attr_reader :param_depth_limit
def initialize(params_class, _key_space_limit=(not_deprecated = true; nil), param_depth_limit)
unless not_deprecated
warn("`second argument `key_space limit` is deprecated and no longer has an effect. Please call with only two arguments, which will be required in a future version of Rack", uplevel: 1)
end
@params_class = params_class
@param_depth_limit = param_depth_limit
end
# Originally stolen from Mongrel, now with some modifications:
# Parses a query string by breaking it up at the '&'. You can also use this
# to parse cookies by changing the characters used in the second parameter
# (which defaults to '&').
#
# Returns an array of 2-element arrays, where the first element is the
# key and the second element is the value.
def split_query(qs, separator = nil, &unescaper)
pairs = []
if qs && !qs.empty?
unescaper ||= method(:unescape)
qs.split(separator ? (COMMON_SEP[separator] || /[#{separator}] */n) : DEFAULT_SEP).each do |p|
next if p.empty?
pair = p.split('=', 2).map!(&unescaper)
pair << nil if pair.length == 1
pairs << pair
end
end
pairs
rescue ArgumentError => e
raise InvalidParameterError, e.message, e.backtrace
end
# Parses a query string by breaking it up at the '&'. You can also use this
# to parse cookies by changing the characters used in the second parameter
# (which defaults to '&').
#
# Returns a hash where each value is a string (when a key only appears once)
# or an array of strings (when a key appears more than once).
def parse_query(qs, separator = nil, &unescaper)
params = make_params
split_query(qs, separator, &unescaper).each do |k, v|
if cur = params[k]
if cur.class == Array
params[k] << v
else
params[k] = [cur, v]
end
else
params[k] = v
end
end
params.to_h
end
# parse_nested_query expands a query string into structural types. Supported
# types are Arrays, Hashes and basic value types. It is possible to supply
# query strings with parameters of conflicting types, in this case a
# ParameterTypeError is raised. Users are encouraged to return a 400 in this
# case.
def parse_nested_query(qs, separator = nil)
params = make_params
split_query(qs, separator).each do |k, v|
_normalize_params(params, k, v, 0)
end
params.to_h
end
# normalize_params recursively expands parameters into structural types. If
# the structural types represented by two different parameter names are in
# conflict, a ParameterTypeError is raised. The depth argument is deprecated
# and should no longer be used, it is kept for backwards compatibility with
# earlier versions of rack.
def normalize_params(params, name, v, _depth=nil)
_normalize_params(params, name, v, 0)
end
# This value is used by default when a parameter is missing (nil). This
# usually happens when a parameter is specified without an `=value` part.
# The default value is an empty string, but this can be overridden by
# subclasses.
def missing_value
String.new
end
private def _normalize_params(params, name, v, depth)
raise ParamsTooDeepError if depth >= param_depth_limit
if !name
# nil name, treat same as empty string (required by tests)
k = after = ''
elsif depth == 0
# Start of parsing, don't treat [] or [ at start of string specially
if start = name.index('[', 1)
# Start of parameter nesting, use part before brackets as key
k = name[0, start]
after = name[start, name.length]
else
# Plain parameter with no nesting
k = name
after = ''
end
elsif name.start_with?('[]')
# Array nesting
k = '[]'
after = name[2, name.length]
elsif name.start_with?('[') && (start = name.index(']', 1))
# Hash nesting, use the part inside brackets as the key
k = name[1, start-1]
after = name[start+1, name.length]
else
# Probably malformed input, nested but not starting with [
# treat full name as key for backwards compatibility.
k = name
after = ''
end
return if k.empty?
v ||= missing_value
if after == ''
if k == '[]' && depth != 0
return [v]
else
params[k] = v
end
elsif after == "["
params[name] = v
elsif after == "[]"
params[k] ||= []
raise ParameterTypeError, "expected Array (got #{params[k].class.name}) for param `#{k}'" unless params[k].is_a?(Array)
params[k] << v
elsif after.start_with?('[]')
# Recognize x[][y] (hash inside array) parameters
unless after[2] == '[' && after.end_with?(']') && (child_key = after[3, after.length-4]) && !child_key.empty? && !child_key.index('[') && !child_key.index(']')
# Handle other nested array parameters
child_key = after[2, after.length]
end
params[k] ||= []
raise ParameterTypeError, "expected Array (got #{params[k].class.name}) for param `#{k}'" unless params[k].is_a?(Array)
if params_hash_type?(params[k].last) && !params_hash_has_key?(params[k].last, child_key)
_normalize_params(params[k].last, child_key, v, depth + 1)
else
params[k] << _normalize_params(make_params, child_key, v, depth + 1)
end
else
params[k] ||= make_params
raise ParameterTypeError, "expected Hash (got #{params[k].class.name}) for param `#{k}'" unless params_hash_type?(params[k])
params[k] = _normalize_params(params[k], after, v, depth + 1)
end
params
end
def make_params
@params_class.new
end
def new_depth_limit(param_depth_limit)
self.class.new @params_class, param_depth_limit
end
private
def params_hash_type?(obj)
obj.kind_of?(@params_class)
end
def params_hash_has_key?(hash, key)
return false if /\[\]/.match?(key)
key.split(/[\[\]]+/).inject(hash) do |h, part|
next h if part == ''
return false unless params_hash_type?(h) && h.key?(part)
h[part]
end
true
end
def unescape(string, encoding = Encoding::UTF_8)
URI.decode_www_form_component(string, encoding)
end
class Params
def initialize
@size = 0
@params = {}
end
def [](key)
@params[key]
end
def []=(key, value)
@params[key] = value
end
def key?(key)
@params.key?(key)
end
# Recursively unwraps nested `Params` objects and constructs an object
# of the same shape, but using the objects' internal representations
# (Ruby hashes) in place of the objects. The result is a hash consisting
# purely of Ruby primitives.
#
# Mutation warning!
#
# 1. This method mutates the internal representation of the `Params`
# objects in order to save object allocations.
#
# 2. The value you get back is a reference to the internal hash
# representation, not a copy.
#
# 3. Because the `Params` object's internal representation is mutable
# through the `#[]=` method, it is not thread safe. The result of
# getting the hash representation while another thread is adding a
# key to it is non-deterministic.
#
def to_h
@params.each do |key, value|
case value
when self
# Handle circular references gracefully.
@params[key] = @params
when Params
@params[key] = value.to_h
when Array
value.map! { |v| v.kind_of?(Params) ? v.to_h : v }
else
# Ignore anything that is not a `Params` object or
# a collection that can contain one.
end
end
@params
end
alias_method :to_params_hash, :to_h
end
end
end