urlEncode和urlDecode

local function urlEncode(s)
s = string.gsub(s, "([^%w%.%- ])", function(c) return string.format("%%%02X", string.byte(c)) end)
return string.gsub(s, " ", "+")
end

local function urlDecode(s)
s = string.gsub(s, '%%(%x%x)', function(h) return string.char(tonumber(h, 16)) end)
return s
end