minor stuff, getting ready for notify

Mike Macgirvin 13 years ago
parent 1ea69ae275
commit 9cc49f27e6

@ -0,0 +1,242 @@
The reason for the MySQL "Lost Connection during query" issue when forking is the fact that the child process inherits the parent's database connection. When the child exits, the connection is closed. If the parent is performing a query at this very moment, it is doing it on an already closed connection, hence the error.
An easy way to avoid this is to create a new database connection in parent immediately after forking. Don't forget to force a new connection by passing true in the 4th argument of mysql_connect():
$pid = pcntl_fork();
if ( $pid == -1 ) {
// Fork failed
} else if ( $pid ) {
// parent process - regenerate our connections in case the kid kills them
$db = new dba($db_host, $db_user, $db_pass, $db_data, $install);
unset($db_host, $db_user, $db_pass, $db_data);
} else {
// We are the child
// Do something with the inherited connection here
// It will get closed upon exit
If you want to execute some code after your php page has been returned to the user. Try something like this -
function index()
function shutdown() {
posix_kill(posix_getpid(), SIGHUP);
// Do some initial processing
echo("Hello World");
// Switch over to daemon mode.
if ($pid = pcntl_fork())
return; // Parent
ob_end_clean(); // Discard the output buffer and close
fclose(STDIN); // Close all of the standard
fclose(STDOUT); // file descriptors as we
fclose(STDERR); // are running as a daemon.
if (posix_setsid() < 0)
if ($pid = pcntl_fork())
return; // Parent
// Now running as a daemon. This process will even survive
// an apachectl stop.
$fp = fopen("/tmp/sdf123", "w");
fprintf($fp, "PID = %s\n", posix_getpid());
while(count($this->currentJobs) >= $this->maxProcesses){
echo "Maximum children allowed, waiting...\n";
duerra at yahoo dot com
02-Jul-2010 02:06
Using pcntl_fork() can be a little tricky in some situations. For fast jobs, a child can finish processing before the parent process has executed some code related to the launching of the process. The parent can receive a signal before it's ready to handle the child process' status. To handle this scenario, I add an id to a "queue" of processes in the signal handler that need to be cleaned up if the parent process is not yet ready to handle them.
I am including a stripped down version of a job daemon that should get a person on the right track.
//A very basic job daemon that you can extend to your needs.
class JobDaemon{
public $maxProcesses = 25;
protected $jobsStarted = 0;
protected $currentJobs = array();
protected $signalQueue=array();
protected $parentPID;
public function __construct(){
echo "constructed \n";
$this->parentPID = getmypid();
pcntl_signal(SIGCHLD, array($this, "childSignalHandler"));
* Run the Daemon
public function run(){
echo "Running \n";
for($i=0; $i<10000; $i++){
$jobID = rand(0,10000000000000);
$launched = $this->launchJob($jobID);
//Wait for child processes to finish before exiting here
echo "Waiting for current jobs to finish... \n";
* Launch a job from the job queue
protected function launchJob($jobID){
$pid = pcntl_fork();
if($pid == -1){
//Problem launching the job
error_log('Could not launch new job, exiting');
return false;
else if ($pid){
// Parent process
// Sometimes you can receive a signal to the childSignalHandler function before this code executes if
// the child script executes quickly enough!
$this->currentJobs[$pid] = $jobID;
// In the event that a signal for this pid was caught before we get here, it will be in our signalQueue array
// So let's go ahead and process it now as if we'd just received the signal
echo "found $pid in the signal queue, processing it now \n";
$this->childSignalHandler(SIGCHLD, $pid, $this->signalQueue[$pid]);
//Forked child, do your deeds....
$exitStatus = 0; //Error code if you need to or whatever
echo "Doing something fun in pid ".getmypid()."\n";
return true;
public function childSignalHandler($signo, $pid=null, $status=null){
//If no pid is provided, that means we're getting the signal from the system. Let's figure out
//which child process ended
$pid = pcntl_waitpid(-1, $status, WNOHANG);
//Make sure we get all of the exited children
while($pid > 0){
if($pid && isset($this->currentJobs[$pid])){
$exitCode = pcntl_wexitstatus($status);
if($exitCode != 0){
echo "$pid exited with status ".$exitCode."\n";
else if($pid){
//Oh no, our job has finished before this parent process could even note that it had been launched!
//Let's make note of it and handle it when the parent process is ready for it
echo "..... Adding $pid to the signal queue ..... \n";
$this->signalQueue[$pid] = $status;
$pid = pcntl_waitpid(-1, $status, WNOHANG);
return true;
function notifier(&$a,$item_id,$parent_id) {
$pid = pcntl_fork();
if ($pid == (-1)) {
notice("Failed to launch background notifier." . EOL );
if ($pid > 0) {
// parent process - regenerate our connections in case the kid kills them
$db = new dba($db_host, $db_user, $db_pass, $db_data, $install);
unset($db_host, $db_user, $db_pass, $db_data);
// go back and finish the page
else {
// We are the child
// fetch item
// if not parent, fetch it
// atomify
// expand list of recipients
// grab the contact records
// foreach recipient
// if no dfrn-id continue
// fetch_url dfrn-notify
// decrypt challenge
// post result
// continue

@ -57,6 +57,12 @@ function item_post(&$a) {
goaway($a->get_baseurl() . "/profile/$profile_uid");

@ -0,0 +1,22 @@
<feed xmlns="http://www.w3.org/2005/Atom"
xmlns:foaf="http://xmlns.com/foaf/0.1" >
<foaf:homepage rdf:resource="$profile_page" />
<foaf:img rdf:resource="$thumb" />
<link href="$link" />
<content type="text/plain" ></content>

@ -0,0 +1,9 @@
You could use proc_open for this:
proc_close(proc_open ("./script.php &", array(), $foo));
The empty array for the output specs prevents opening any pipes to the new
process, so proc_open doesn't wait for the execution of script.php to
finish - the last parameter is just there because it has to be.
proc_close() closes the process immediately, so your PHP script doesn't