93 lines
2.9 KiB
Ruby
93 lines
2.9 KiB
Ruby
class UrlEncodedPairParser < StringScanner #:nodoc:
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attr_reader :top, :parent, :result
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def initialize(pairs = [])
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super('')
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@result = {}
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pairs.each { |key, value| parse(key, value) }
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end
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KEY_REGEXP = %r{([^\[\]=&]+)}
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BRACKETED_KEY_REGEXP = %r{\[([^\[\]=&]+)\]}
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# Parse the query string
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def parse(key, value)
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self.string = key
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@top, @parent = result, nil
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# First scan the bare key
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key = scan(KEY_REGEXP) or return
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key = post_key_check(key)
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# Then scan as many nestings as present
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until eos?
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r = scan(BRACKETED_KEY_REGEXP) or return
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key = self[1]
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key = post_key_check(key)
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end
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bind(key, value)
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end
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private
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# After we see a key, we must look ahead to determine our next action. Cases:
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#
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# [] follows the key. Then the value must be an array.
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# = follows the key. (A value comes next)
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# & or the end of string follows the key. Then the key is a flag.
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# otherwise, a hash follows the key.
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def post_key_check(key)
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if scan(/\[\]/) # a[b][] indicates that b is an array
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container(key, Array)
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nil
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elsif check(/\[[^\]]/) # a[b] indicates that a is a hash
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container(key, Hash)
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nil
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else # End of key? We do nothing.
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key
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end
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end
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# Add a container to the stack.
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def container(key, klass)
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type_conflict! klass, top[key] if top.is_a?(Hash) && top.key?(key) && ! top[key].is_a?(klass)
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value = bind(key, klass.new)
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type_conflict! klass, value unless value.is_a?(klass)
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push(value)
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end
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# Push a value onto the 'stack', which is actually only the top 2 items.
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def push(value)
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@parent, @top = @top, value
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end
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# Bind a key (which may be nil for items in an array) to the provided value.
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def bind(key, value)
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if top.is_a? Array
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if key
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if top[-1].is_a?(Hash) && ! top[-1].key?(key)
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top[-1][key] = value
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else
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top << {key => value}.with_indifferent_access
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push top.last
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value = top[key]
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end
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else
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top << value
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end
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elsif top.is_a? Hash
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key = CGI.unescape(key)
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parent << (@top = {}) if top.key?(key) && parent.is_a?(Array)
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top[key] ||= value
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return top[key]
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else
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raise ArgumentError, "Don't know what to do: top is #{top.inspect}"
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end
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return value
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end
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def type_conflict!(klass, value)
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raise TypeError, "Conflicting types for parameter containers. Expected an instance of #{klass} but found an instance of #{value.class}. This can be caused by colliding Array and Hash parameters like qs[]=value&qs[key]=value. (The parameters received were #{value.inspect}.)"
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end
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end |