Inverse of CGI.parse

[kyberfabrikken]

CGI.parse takes a querystring and returns a hash. I'm looking for a way to do the inverse. Any suggestions?

[Arlen]

given "hash" as a hash, try hash.to_query and see if that's what you're looking for.

[kyberfabrikken]

Close, but not quite. CGI.parse gives back an array of values, even when there is just one. to_query interprets this as the value being present multiple times. I just wrote my own implementation, but if a standard solution existed, I would have preferred to use that.

[Majglow]

my_hash.map { |key, value| "#{key}=#{CGI.escape(value)}" }.join('&')

[kyberfabrikken]

Not quite. The result from CGI.parse looks like this:

irb(main):002:0> CGI.parse "foo=42&bar[]=1&bar[]=2&bar[]=3"
=> {"bar[]"=>["1", "2", "3"], "foo"=>["42"]}

Which does make sense, but also means that the serialization code becomes a bit more tricky. Anyway, I figured it out - it's just that if some kind of standard function existed, I would rather have used that.

[kyberfabrikken]

Just in case somebody else needs this, here's the code I came up with:

require 'uri'
def hash_to_query(h)
  h.map do |k, v|
    v.map do |value|
      (value.nil?) ? URI.encode(k.to_s) : "%s=%s" % [URI.encode(k.to_s), URI.encode(value.to_s)]
    end
  end.flatten.join("&")
end