function urldecode(s)
  s = s:gsub('+', ' ')
       :gsub('%%(%x%x)', function(h)
                           return string.char(tonumber(h, 16))
                         end)
  return s
end
 
function parseurl(s)
  local ans = {}
  for k,v in s:gmatch('([^&=?]-)=([^&=?]+)' ) do
    ans[ k ] = urldecode(v)
  end
  return ans
end
 
local a = "http://w...content-available-to-author-only...e.com/test.html?key1=val1&key2=val2&key3=val3"
t = parseurl(a)
print(t.key1 )
print(t.key2)
 

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