Running into ERR_CONNECTION_RESET when checking multiple links - php

Question

I want to write a small PHP script which checks the existence of files on a server.
The files URLs have the following format:
http://update.example.com/Files/Updates/7.25.2.128/application7_25_2_128_de_FullInstallerx64.exe
Now I want to loop through the version numbers and check if the file exists.
function checkAllUrls() {
$revisionNumber = 25;
$minorNumber = 2;
$buildNumber = 128;
for ($x = $buildNumber; $x > 0; $x--) {
file_put_contents('log.txt', "Checking Build: $x", FILE_APPEND);
$combinedUrl = 'http://update.example.com/Files/Updates/6.' . $revisionNumber . '.' . $minorNumber . '.' . $x . '/application7_' . $revisionNumber . '_' . $minorNumber . '_' . $x . '_de_FullInstallerx64.exe';
$urlHeaders = #get_headers($combinedUrl);
if(!$urlHeaders || $urlHeaders[0] == 'HTTP/1.1 404 Not Found') {
$exists = "no";
file_put_contents('log.txt', "\n" . $combinedUrl . " - " . "does not exist. \n", FILE_APPEND);
} else {
$exists = "yes";
file_put_contents('log.txt', "\n" . $combinedUrl . " - " . "exists. \n", FILE_APPEND);
}
sleep(3);
}
}
The problem is, that even if using sleep() with 3 seconds, the links / files are not checked after a couple of links.
Afterwards I cannot open any of the valid links in my browser any more getting ERR_CONNECTION_RESET in return. At first I was afraid, that I kind of crashed the server, but accessing via VPN still lets me download the file.
Can anybody explain to my, why this is happening and how I can avoid this behaviour?
Thanks in advance.

Answer 1

maybe your problem don't use multiple request. Try this multiple curl request method.
function checkAllUrls() {
$revisionNumber = 25;
$minorNumber = 2;
$buildNumber = 128;
$multiCurl = curl_multi_init();
$curlArray = array();
for ($x = $buildNumber; $x > 0; $x--) {
$combinedUrl = 'http://update.example.com/Files/Updates/6.' . $revisionNumber . '.' . $minorNumber . '.' . $x . '/application7_' . $revisionNumber . '_' . $minorNumber . '_' . $x . '_de_FullInstallerx64.exe';
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $combinedUrl);
curl_setopt($curl, CURLOPT_FILETIME, true);
curl_setopt($curl, CURLOPT_NOBODY, true);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HEADER, true);
curl_multi_add_handle($multiCurl,$curl);
$curlArray[] = ['curl' => $curl, 'build' => $x] ;
}
$i = NULL;
do {
$x = curl_multi_exec($multiCurl, $i);
} while ($i > 0);
foreach ($curlArray as $k => $v) {
file_put_contents('log.txt', "Checking Build: ".$v['build'], FILE_APPEND);
$httpCode = curl_getinfo($v['curl'], CURLINFO_HTTP_CODE);
$combinedUrl = curl_getinfo($v['curl'], CURLINFO_EFFECTIVE_URL);
if($httpCode === 404) {
$exists = "no";
file_put_contents('log.txt', "\n" . $combinedUrl . " - " . "does not exist. \n", FILE_APPEND);
} else {
$exists = "yes";
file_put_contents('log.txt', "\n" . $combinedUrl . " - " . "exists. \n", FILE_APPEND);
}
curl_multi_remove_handle($multiCurl, $v['curl']);
}
curl_multi_close($multiCurl);
}