function var_dump(data, max_level, prefix)   
	if type(prefix) ~= "string" then   
		prefix = ""  
	end   
	if type(data) ~= "table" then   
		dump_html(prefix .. tostring(data))   
	else  
		dump_html(tostring(data))   
		if max_level ~= 0 then   
			local prefix_next = prefix .. "    "  
			dump_html(prefix .. "{")   
			for k,v in pairs(data) do   
				dump_html(prefix_next .. k .. " = ") 
				if type(v) ~= "table" or (type(max_level) == "number" and max_level <= 1) then   
					dump_html(v)   
				else  
					if max_level == nil then   
						var_dump(v, nil, prefix_next)   
					else  
						var_dump(v, max_level - 1, prefix_next)   
					end   
				end   
			end   
			dump_html(prefix .. "}")   
		end   
	end   
end  


function dump_html(str)
	if str ~= nil then
		ngx.header.content_type = "text/html"
        ngx.say(str)
	end
end