 
Subject
Here is a Lua script we put together that measures the latency of a web host, the time to resolve the host, and the time to retrieve a page:
-- time to resolve host, time to ping host, time to get host/page
print ("\"page name\",\"host latency ms\",\"dns resolve ms\",\"page receive ms\"")
-- fromCSV from http://www.lua.org/pil/20.4.html
function fromCSV (s)
s = s .. ',' -- ending comma
local t = {} -- table to collect fields
local fieldstart = 1
repeat
-- next field is quoted? (start with `"'?)
if string.find(s, '^"', fieldstart) then
local a, c
local i = fieldstart
repeat
-- find closing quote
a, i, c = string.find(s, '"("?)', i+1)
until c ~= '"' -- quote not followed by quote?
if not i then error('unmatched "') end
local f = string.sub(s, fieldstart+1, i-1)
table.insert(t, (string.gsub(f, '""', '"')))
fieldstart = string.find(s, ',', i) + 1
else -- unquoted; find next comma
local nexti = string.find(s, ',', fieldstart)
table.insert(t, string.sub(s, fieldstart, nexti-1))
fieldstart = nexti + 1
end
until fieldstart > string.len(s)
return t
end
require("cURL")
require("socket")
while (6 < 9) do
file_config = assert(io.open("config.csv", "r"))
for line in file_config:lines() do
t = fromCSV(line)
os.execute("ping -c 1 "..t[2].." | grep round > ping_result.txt")
file_ping = assert(io.open("ping_result.txt", "r"))
line=file_ping:read()
if line == nil then
ping_time="no response"
else
start=string.find(line,"/",32)
ping_time=string.sub(line,33,start-5)
file_ping:close()
end
begin_time=socket.gettime()
master= socket.dns.toip(t[2])
if master ==nil then
dns_time=("can't resolve")
else
dns_time=(socket.gettime()-begin_time)
file_page = io.open("mcjk", "w")
c = cURL.easy_init()
c:setopt_url("http://"..t[2]..t[3])
begin_time=socket.gettime()
c:perform({writefunction = function(str)
file_page:write(str)
end})
page_retrieve_time=(socket.gettime()-begin_time)
file_page:close()
end
print (string.format ("\"%s\",\"%.0f\",\"%.4f\",\"%.3f\""
,t[1],ping_time,dns_time,page_retrieve_time))
end
file_config:close()
end
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The CSV file has this format:
Front Page,www.seanet.com,/index.html
Keywords Page,www.oracle.com,/index.html
Search Page,www.sgi.com,/index.html
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Here is an example using the CSV file above:
srv-8:lua usr4$ lua w.lua
"page name","host latency ms","dns resolve ms","page receive ms"
"Front Page","77","0.0005","0.492"
"Keywords Page","133","0.0004","0.556"
"Search Page","127","0.0003","0.443"
"Front Page","70","0.0002","0.374"
"Keywords Page","100","0.0001","0.554"
"Search Page","113","0.0001","0.599"
"Front Page","135","0.0001","0.507"
"Keywords Page","96","0.0002","0.543"
"Search Page","104","0.0001","0.543"
"Front Page","65","0.0001","0.378"
"Keywords Page","126","0.0000","0.557"
"Search Page","110","0.0000","0.549"
.
.
.
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Run this out to a text file and open in Excel to get a spreadsheet of the resulting times:
srv-8:lua usr4$ lua w.lua > out.txt
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| People: | |
| Places: | |
| Things: | |
| Times: | |
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