Multi-Tasking and Multi-Threading Support
To perform parallel execution in PHP without forking a new process, you may
take advantage of one of these new facilities:
1. Pagelet Server
The pagelet server is similar to a CURL call to localhost. Look for "Pagelet
Server" in compiled program's options for how to set it up. The new pagelet
server functions work like this:
// This starts a pagelet server thread to process the URL just as if
// it's a new web request with specified headers and post data.
// The request method would be GET if the post data is empty.
$task = pagelet_server_task_start($url, $headers, $post_data);
// Main thread can now do extra work while pagelet server is processing.
...
// Optionally make this non-blocking call any time to check status.
$status = pagelet_server_task_status($task);
...
// Finally, we make a blocking call to wait for pagelet server's result,
// which is the entire output of the web page, with response headers and
// status code. The status code is set to 0 if a flushed partial response is
// successfully returned and the pagelet server is still active.
//
// A timeout of 0 is interpreted as an infinite timeout. The status code is
// set to -1 in the event of a timeout.
$headers = array(); $code = 0;
$result = pagelet_server_task_result($task, $headers, $code,
$timeout_ms);
2. Xbox Tasks
The xbox task system is designed to provide cross-box messaging as described in
"server.xbox_server" documentation. The xbox task system may also be used to
execute a task on the local machine in a separate thread. Here is an example:
// We start an xbox task by sending to localhost a message.
$task = xbox_task_start($message);
// Main thread can now do extra work while xbox task is processing.
...
// Optionally make this non-blocking call any time to check status.
$status = xbox_task_status($task);
...
// Finally, we make a blocking call to check message processing returns.
$ret = null;
$code = xbox_task_result($task, $timeout_ms, $ret);
On the message processing side, one has to implement a PHP function like this:
function xbox_process_message($msg) {
...
return $ret;
}
Note that an xbox thread starts its execution with its own global state without
sharing anything with main thread, other than $msg and $ret that are passed
between these threads at enter and exit points.