XT downloader/updater

--XT downloader/updater code
--Should be placed before programs that use XT
repeat
    cprint=print;
    cprintErr=printError;

    --cprint=function()end          --Uncomment these if you'd like the updater
    --cprintErr=function()end       --to not print log messages (unrecommended)

    local dontUpdate=false;         --Set this to true if you only want the downloader to download, not update or check for updates

    local ver;
    if xt then
        if type(xt.version)=="number" then
            if dontUpdate then
                cprint("Set to not-update mode, using offline XT version");
                cprintErr("Beware of errors");
                break;
            end
            ver=xt.version;
        end
    elseif fs.exists("xt") then
        local handle=fs.open("xt","r");
        ver=tonumber(handle.readLine():sub(7,9));
        handle.close();
        if ver==nil then
            cprint("A non-XtraTurtles file has been found on \"xt\".");
            cprint("Overwrite it? (\"yes\"/\"no\")");
            local res=read();
            if res~="yes" then
                print("Ok.");
                error();
            end
        else
            if dontUpdate then
                cprint("Set to not-update mode, using downloaded XT version");
                cprintErr("Beware of errors");
            end
        end
    end

    if not dontUpdate then
        cprint("Checking for XT updates...");
        local response=http.get("http://pastebin.com/raw.php?i=L5jF84nW");
        if response then
            local newVer=tonumber(response.readLine());
            if newVer==nil then
                response.close();
                cprint("Corrupted online version.");
                if ver==nil then
                    error();
                else
                    cprint("But there is an offline version, going on anyways");
                    cprintErr("Beware of errors");
                end
            else
                if type(ver)=="number" then
                    if ver>=newVer then
                        cprint("XT up-to-date");
                        break;
                    end
                end
                local xtresp=http.get("http://pastebin.com/raw.php?i="..response.readLine());
                response.close();
                if xtresp then
                    local handle=fs.open("xt","w");
                    handle.write(xtresp.readAll());
                    handle.close();
                    xtresp.close();
                    if ver then
                        cprint("XT "..newVer.." downloaded. Previous was "..ver);
                    else
                        cprint("XT "..newVer.." downloaded. Previous didnt have a version number/didnt exist");
                    end
                else
                    cprint("Error downloading new version, but going on anyways.");
                    cprintErr("Beware of errors");
                end
            end
        else
            if type(ver)=="number" then
                cprint("XT found, cant check for updates, but going on anyways.");
                cprintErr("Beware of errors");
            else
                cprint("XT not found and cant download it");
                error();
            end
        end
    end
until true
if not xt then
    os.loadAPI("xt");
end
--End of XT updater/downloader