-- Web server log file, "combined" format with vhost in 2nd position

--[[ 192.161.191.101 www.wellho.net - [05/Nov/2015:03:35:03 +0000] "GET
/resources/Y202.html HTTP/1.1" 200 26241 "-" "Mozilla/5.0 (Windows NT 6.1)
AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36" ]]

--[[ Build up example at end of course ...
1. Wrote short main test program
2. Wrote "classes" / tables of functions that it used
3. Got that working
4. Enhanced main program to do other things, adding extra class code
        to be done ... (in other word 'this is how far the example has gone')
5. Refactor to save time and space using metatables, etc
6. Separate out utilisites and "classes" into separate files for late reuse
7. Write it up and test it more
8. Take a long, cold drink (or a warm beer)
]]

Access = {}
function Access.gethost(access) return access[2] end
function Access.getstatus(access) return access[9] end
function Access.factory(raw)
        local hit = {}
        local fn = 1
        local v
        for v in string.gmatch(raw,"%S+") do
                hit[fn] = v
                fn = fn + 1
        end
        hit["getServer"] = Access.gethost -- Should really use metatable technique!
        hit["getStatus"] = Access.getstatus
        return hit
end

-- Main Application -----------------------------------

if not arg[1] then -- Parameter needed
        print("Usage: " .. arg[0] .. " {logFileName}")
        return
end

fh, err = io.open(arg[1],"r") -- Input file not available
if not fh then
        print ("Nah - " .. err)
        return
end

total = 0
counter = {}
while true do
        lyne = fh:read()
        if not lyne then break end
        current = Access.factory(lyne) -- Make me an object
        total = total + 1
        serverName = current:getServer()
        if counter[serverName] then
                counter[serverName] = counter[serverName] + 1
        else
                counter[serverName] = 1
        end
end

print("Total lines of data: " .. total)

-- table.sort(counter) Will NOT work ... sort works on an indexed table.

-- Following code sorts by host name

hosts = {}
for k,v in pairs(counter) do
        hosts[#hosts+1] = k
end
table.sort(hosts)
for k,v in ipairs(hosts) do
        print (string.format("%-30s %6d",v,counter[v]))
end

print (" ----------------------------")
-- resort by number of accesses

function bycount(this, that)
        return counter[this] > counter[that]
end

table.sort(hosts,bycount)
for k,v in ipairs(hosts) do
        print (string.format("%-30s %6d",v,counter[v]))
end

--[[ Sample run

WomanWithCat:ln15 grahamellis$ lua log_counter ac_20151106
Total lines of data: 171578
chs73.info 97
grahamellis.co.uk 61
lisa-ellis.co.uk 4
melksh.am 176
railcustomer.info 26
readtheirobituary.com 22
sheepbingo.co.uk 21
thebutlerdidit.info 8
transwilts.org.uk 74
twhc.org.uk 2876
www.across-the-pond.co.uk 211
www.consultations.org.uk 3
www.firstgreatwestern.info 55277
www.melkshamchamber.org.uk 1194
www.passenger.chat 3
www.savethetrain.org.uk 544
www.twcrp.org.uk 1707
www.wellho.net 108706
www.wellhousemanor.co.uk 568
 ----------------------------
www.wellho.net 108706
www.firstgreatwestern.info 55277
twhc.org.uk 2876
www.twcrp.org.uk 1707
www.melkshamchamber.org.uk 1194
www.wellhousemanor.co.uk 568
www.savethetrain.org.uk 544
www.across-the-pond.co.uk 211
melksh.am 176
chs73.info 97
transwilts.org.uk 74
grahamellis.co.uk 61
railcustomer.info 26
readtheirobituary.com 22
sheepbingo.co.uk 21
thebutlerdidit.info 8
lisa-ellis.co.uk 4
www.consultations.org.uk 3
www.passenger.chat 3
WomanWithCat:ln15 grahamellis$

]]