I'm working on a bit of python code that uses mechanize to grab data from another website. Because of the complexity of the website the code takes 10-30 seconds to complete. It has to work its way through a couple pages and such.
I plan on having this piece of code being called fairly frequently. I'm wondering the best way to implement something like this without causing a huge server load. Since I'm fairly new to python I'm not sure how the language works.
If the code is in the middle of processing one request and another user calls the code, can two instances of the code run at once? Is there a better way to implement something like this?
I want to design it in a way that it can complete the hefty tasks without being too taxing on the server.
My data grabbing scripts all use caching to minimize load on the server. Be sure to use HTTP tools such as, "If-Modified-Since", "If-None-Match", and "Accept-Encoding: gzip".
Also consider using the multiprocessing module so that you can run requests in parallel.
Here is an excerpt from my downloader script:
def urlretrieve(url, filename, cache, lock=threading.Lock()):
'Read contents of an open url, use etags and decompress if needed'
request = urllib2.Request(url)
request.add_header('Accept-Encoding', 'gzip')
with lock:
if ('etag ' + url) in cache:
request.add_header('If-None-Match', cache['etag ' + url])
if ('date ' + url) in cache:
request.add_header('If-Modified-Since', cache['date ' + url])
try:
u = urllib2.urlopen(request)
except urllib2.HTTPError as e:
return Response(e.code, e.msg, False, False)
content = u.read()
u.close()
compressed = u.info().getheader('Content-Encoding') == 'gzip'
if compressed:
content = gzip.GzipFile(fileobj=StringIO.StringIO(content), mode='rb').read()
written = writefile(filename, content)
with lock:
etag = u.info().getheader('Etag')
if etag:
cache['etag ' + url] = etag
timestamp = u.info().getheader('Date')
if timestamp:
cache['date ' + url] = timestamp
return Response(u.code, u.msg, compressed, written)
The cache is an instance of shelve, a persistent dictionary.
Calls to the downloader are parallelized with imap_unordered() on a multiprocessing Pool instance.
You can run more than one python process at a time. As for causing excessive load on the server that can only be alleviated by making sure either you only have one instance running at any given time or some other number of processes, say two. To accomplish this you can look at using a lock file or some kind of system flag, mutex ect...
But, the best way to limit excessive use is to limit the number of tasks running concurrently.
The basic answer is "you can run as many instances of your program you want, as long as they don't share critical ressources (like a database)".
In real-world, you often need to use the "multiprocessing module" and to properly design your application to handle concurrency and avoid corrupted states or deadlocks.
By the way, design of multiprocesses app's is beyond the scope of a simple question on StackOverflow...
Related
I have some concerns about my PHP file, which is processing too long.
I'm using XAMPP.
The problem is, that when i use too many methods of my classes, the PHP file loads too slow or it executes too slow.
Here's my example code:
class Sample {
public function show() {
echo 'test';
}
}
$classObject = new Sample();
$classObject->show();
When i run the PHP code above, it takes only i think 1.5s, but if i add more method calls like this:
$classObject = new Sample();
$classObject->show();
$classObject->show();
the PHP code takes almost 3s while executing.
Is there a way to solve this problem?
I already found out what is the problem is when i used oop style php while fetching data from my database it takes long secs before it gonna execute but when I used procedural php style it executes faster.
Firstly, you should take a look at some PHP debugging techniques, because i dont see any attempt of debugging in your code sample.
To your problem:
What you've described is an issue, that can be but must not be a fault of PHP. The thing is, you have to understand how request processing works ... in your case (XAMPP + PHP) it goes like this:
WebServer start:
XAMPP starts Apache (or Tomcat/or whatever WebServer you're using)
Apache starts PHP binary
PHP loads the configuration (php.ini)
The request:
You'll start a web browser (doesn't matter which one)
You'll enter a web address (with or without a specific path - URI)
Then happens some DNS things - that's NOT important for you now
The browser sends a plain-text document on the server via the HTTP protocol, which communicates over TCP - also not so important for you at this time
The WebServer receives a HTTP request and begins the processing
The WebServer runs your PHP script in the already running PHP binary and awaits the ouput
The response
Then the WebServer takes the output of your script and sends it back to the browser
The browser decides (by the headers) how (and if) the content will be displayed to you
Then the browser begins displaying the response content - in your case a HTML or a plain-text document
While drawing the document, the browser begins processing all JavaScript and CSS on the way (up to down)
With this knowledge you need to find out WHERE on the way is the delay taking up time.
The first thing you should do, is to take a look on how long your script is being processed, so:
<?php
$start_time = microtime(true);
$classObject = Sample();
$classObject->show();
$classObject->show();
echo 'Processing took: ' . number_format(microtime(true) - $start_time, 6, '.', '') . ' seconds';
Then, you should look into some Developer Tool your browser provides, for example DevTools in Google Chrome (very good for debugging, though not the best) - hit F12 to open it.
You'll see something like this:
Time is the duration between the time, the request was fully sent and the time, the response was fully received
Load is the sum of durations of all the requests that were done at that moment
Finish is the duration between the time the first request was fully sent and the time the last response was fully received
DOMContentLoaded is the duration of rendering the entire document (browser/client side)
When you have all of this specific duartions, you can decide, where probably will be the problem :)
im wondering if theres a way to run a code in a loop as a process and interacting with it from a different script. I know sockets listen to incoming requests but im referring to internal usage, without requests.
Standard approach:
Use pcntl-signal() and posix-kill() functions to interact by standard or user-defined signals.
Pros:
PHP built-in, ready for use functions. No need to reinvent wheels.
POSIX compatibility.
Cons:
You can only send defined signals to a script. Not values.
One-way interaction.
Example of listening script:
<?php
pcntl_signal(SIGTERM, 'sig_handler');
pcntl_signal(SIGUSR1, 'sig_handler');
echo 'Run... PID: ' . getmypid() . PHP_EOL;
$finish = false;
while (!$finish) {
pcntl_signal_dispatch();
}
echo 'Shutdown...' . PHP_EOL;
function sig_handler($signal) {
global $finish;
echo 'Received signal: ' . $signal . PHP_EOL;
switch ($signal) {
case SIGTERM:
$finish = true;
break;
case SIGUSR1:
echo 'Processing SIGUSR1 signal...' . PHP_EOL;
break;
}
}
Non-standard approach:
You can implement interaction with script using tools like database, files, sockets, pipes.
Pros:
Functionality depends only on realization.
Cons:
You need to implement protocol for interaction and support it in your script.
I would say first you set up your script to run in the background. You can implement it yourself (using fork) or use existing libraries.
https://www.google.co.jp/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=php%20daemon
Then you define a protocol to communicate. There are many way to implements that, from simple to complex, depending on your needs.
A simple way for example would be to define a folder somewhere in the server that your script reads on the regular basis (loop + sleep). When a file is added, the script reads it, execute the instruction in it, and delete it.
Nope, you cannot directly access another running script, as each script runs on it's own resource sandbox (memory, file descriptors). You'd also need to know it's PID in order to access it, and then after, you'd need some hacking tools to get into that process space.
This may not full fill your requirement. But will works:
Try logging the status to a text file from the first script and read it frequently from the second script to know what is the current status of first script.
I have a situation, which is with similar approach.
I'm starting independent processes by forking and not wait for them - only start. But I've created control structure in a database. There every children process is storing it's state but also observes a control flag and when this flag is up - then children stops immediately. The children processes stores time-stamped records in another table and that let's me to check what process where is with it's task.
In control structure is stored also processes pids and it is possible to send signals to them.
I think this can be useful in your situation too.
when php process starts it take all its requirements for example variables linked pages etc etc.. and show result after it finishes its execution, and after it is completed execution you cant do anything but to re-execute.
its like going to picnic on moon and coming back to home after its over, so no one can disturb you while you are in your picnic. :D
I have to scrap a web site where i need to fetch multiple URLs and then process them one by one. The current process somewhat goes like this.
I fetch a base URL and get all secondary URLs from this page, then for each secondary url I fetch that URL, process found page, download some photos (which takes quite a long time) and store this data to database, then fetch next URL and repeat the process.
In this process, I think I am wasting some time in fetching secondary URL at the start of each iteration. So I am trying to fetch next URLs in parallel while processing first iteration.
The solution in my mind is, from main process call a PHP script, say downloader, which will download all the URL (with curl_multi or wget) and store them in some database.
My questions are
How to call such downloder asynchronously, I don't want my main script to wait till downloder completes.
Any location to store downloaded data, such as shared memory. Of course, other than database.
There any chances that data gets corrupt while storing and retrieving, how to avoid this?
Also, please guide me know if anyone have a better plan.
When I hear someone uses curl_multi_exec it usually turns out they just load it with, say, 100 urls, then wait when all complete, and then process them all, and then start over with the next 100 urls... Blame me, I was doing so too, but then I found out that it is possible to remove/add handles to curl_multi while something is still in progress, And it really saves a lot of time, especially if you reuse already open connections. I wrote a small library to handle queue of requests with callbacks; I'm not posting full version here of course ("small" is still quite a bit of code), but here's a simplified version of the main thing to give you the general idea:
public function launch() {
$channels = $freeChannels = array_fill(0, $this->maxConnections, NULL);
$activeJobs = array();
$running = 0;
do {
// pick jobs for free channels:
while ( !(empty($freeChannels) || empty($this->jobQueue)) ) {
// take free channel, (re)init curl handle and let
// queued object set options
$chId = key($freeChannels);
if (empty($channels[$chId])) {
$channels[$chId] = curl_init();
}
$job = array_pop($this->jobQueue);
$job->init($channels[$chId]);
curl_multi_add_handle($this->master, $channels[$chId]);
$activeJobs[$chId] = $job;
unset($freeChannels[$chId]);
}
$pending = count($activeJobs);
// launch them:
if ($pending > 0) {
while(($mrc = curl_multi_exec($this->master, $running)) == CURLM_CALL_MULTI_PERFORM);
// poke it while it wants
curl_multi_select($this->master);
// wait for some activity, don't eat CPU
while ($running < $pending && ($info = curl_multi_info_read($this->master))) {
// some connection(s) finished, locate that job and run response handler:
$pending--;
$chId = array_search($info['handle'], $channels);
$content = curl_multi_getcontent($channels[$chId]);
curl_multi_remove_handle($this->master, $channels[$chId]);
$freeChannels[$chId] = NULL;
// free up this channel
if ( !array_key_exists($chId, $activeJobs) ) {
// impossible, but...
continue;
}
$activeJobs[$chId]->onComplete($content);
unset($activeJobs[$chId]);
}
}
} while ( ($running > 0 && $mrc == CURLM_OK) || !empty($this->jobQueue) );
}
In my version $jobs are actually of separate class, not instances of controllers or models. They just handle setting cURL options, parsing response and call a given callback onComplete.
With this structure new requests will start as soon as something out of the pool finishes.
Of course it doesn't really save you if not just retrieving takes time but processing as well... And it isn't a true parallel handling. But I still hope it helps. :)
P.S. did a trick for me. :) Once 8-hour job now completes in 3-4 mintues using a pool of 50 connections. Can't describe that feeling. :) I didn't really expect it to work as planned, because with PHP it rarely works exactly as supposed... That was like "ok, hope it finishes in at least an hour... Wha... Wait... Already?! 8-O"
You can use curl_multi: http://www.somacon.com/p537.php
You may also want to consider doing this client side and using Javascript.
Another solution is to write a hunter/gatherer that you submit an array of URLs to, then it does the parallel work and returns a JSON array after it's completed.
Put another way: if you had 100 URLs you could POST that array (probably as JSON as well) to mysite.tld/huntergatherer - it does whatever it wants in whatever language you want and just returns JSON.
Aside from the curl multi solution, another one is just having a batch of gearman workers. If you go this route, I've found supervisord a nice way to start a load of deamon workers.
Things you should look at in addition to CURL multi:
Non-blocking streams (example: PHP-MIO)
ZeroMQ for spawning off many workers that do requests asynchronously
While node.js, ruby EventMachine or similar tools are quite great for doing this stuff, the things I mentioned make it fairly easy in PHP too.
Try execute from PHP, python-pycurl scripts. Easier, faster than PHP curl.
We would like to implement a method that checks mysql load or total sessions on server and
if this number is bigger than a value then the next visitor of the website is redirected to a static webpage with a message Too many users try later.
One way I implemented it in my website is to handle the error message MySQL outputs when it denies a connection.
Sample PHP code:
function updateDefaultMessage($userid, $default_message, $dttimestamp, $db) {
$queryClients = "UPDATE users SET user_default_message = '$default_message', user_dtmodified = '$dttimestamp' WHERE user_id = $userid";
$resultClients = mysql_query($queryClients, $db);
if (!$resultClients) {
log_error("[MySQL] code:" . mysql_errno($db) . " | msg:" . mysql_error($db) . " | query:" . $queryClients , E_USER_WARNING);
$result = false;
} else {
$result = true;
}
}
In the JS:
function UpdateExistingMsg(JSONstring)
{
var MessageParam = "msgjsonupd=" + JSON.encode(JSONstring);
var myRequest = new Request({url:urlUpdateCodes, onSuccess: function(result) {if (!result) window.open(foo);} , onFailure: function(result) {bar}}).post(MessageParam);
}
I hope the above code makes sense. Good luck!
Here are some alternatives to user-lock-out that I have used in the past to decrease load:
APC Cache
PHP APC cache (speeds up access to your scripts via in memory caching of the scripts): http://www.google.com/search?gcx=c&ix=c2&sourceid=chrome&ie=UTF-8&q=php+apc+cache
I don't think that'll solve "too many mysql connections" for you, but it should really really help your website's speed in general, and that'll help mysql threads open and close more quickly, freeing resources. It's a pretty easy install on a debian system, and hopefully anything with package management (perhaps harder if you're using a if you're using a shared server).
Cache the results of common mysql queries, even if only within the same script execution. If you know that you're calling for certain data in multiple places (e.g. client_info() is one that I do a lot), cache it via a static caching variable and the info parameter (e.g.
static $client_info;
static $client_id;
if($incoming_client_id == $client_id){
return $client_info;
} else {
// do stuff to get new client info
}
You also talk about having too many sessions. It's hard to tell whether you're referring to $_SESSION sessions, or just browsing users, but too many $_SESSION sessions may be an indication that you need to move away from use of $_SESSION as a storage device, and too many browsing users, again, implies that you may want to selectively send caching headers for high use pages. For example, almost all of my php scripts return the default caching, which is no cache, except my homepage, which displays headers to allow browsers to cache for a short 1 hour period, to reduce overall load.
Overall, I would definitely look into your caching procedures in general in addition to setting a hard limit on usage that should ideally never be hit.
This should not be done in PHP. You should do it naturally by means of existing hard limits.
For example, if you configure Apache to a known maximal number of clients (MaxClients), once it reaches the limit it would reply with error code 503, which, in turn, you can catch on your nginx frontend and show a static webpage:
proxy_intercept_errors on;
error_page 503 /503.html;
location = /503.html {
root /var/www;
}
This isn't hard to do as it may sound.
PHP isn't the right tool for the job here because once you really hit the hard limit, you will be doomed.
The seemingly simplest answer would be to count the number of session files in ini_get("session.save_path"), but that is a security problem to have access to that directory from the web app.
The second method is to have a database that atomically counts the number of open sessions. For small numbers of sessions where performance really isn't an issue, but you want to be especially accurate to the # of open sessions, this will be a good choice.
The third option that I recommend would be to set up a chron job that counts the number of files in the ini_get('session.save_path') directory, then prints that number to a file in some public area on the filesystem (only if it has changed), visible to the web app. This job can be configured to run as frequently as you'd like -- say once per second if you want better resolution. Your bootstrap loader will open this file for reading, check the number, and give the static page if it is above X.
Of course, this third method won't create a hard limit. But if you're just looking for a general threshold, this seems like a good option.
I work on a somewhat large web application, and the backend is mostly in PHP. There are several places in the code where I need to complete some task, but I don't want to make the user wait for the result. For example, when creating a new account, I need to send them a welcome email. But when they hit the 'Finish Registration' button, I don't want to make them wait until the email is actually sent, I just want to start the process, and return a message to the user right away.
Up until now, in some places I've been using what feels like a hack with exec(). Basically doing things like:
exec("doTask.php $arg1 $arg2 $arg3 >/dev/null 2>&1 &");
Which appears to work, but I'm wondering if there's a better way. I'm considering writing a system which queues up tasks in a MySQL table, and a separate long-running PHP script that queries that table once a second, and executes any new tasks it finds. This would also have the advantage of letting me split the tasks among several worker machines in the future if I needed to.
Am I re-inventing the wheel? Is there a better solution than the exec() hack or the MySQL queue?
I've used the queuing approach, and it works well as you can defer that processing until your server load is idle, letting you manage your load quite effectively if you can partition off "tasks which aren't urgent" easily.
Rolling your own isn't too tricky, here's a few other options to check out:
GearMan - this answer was written in 2009, and since then GearMan looks a popular option, see comments below.
ActiveMQ if you want a full blown open source message queue.
ZeroMQ - this is a pretty cool socket library which makes it easy to write distributed code without having to worry too much about the socket programming itself. You could use it for message queuing on a single host - you would simply have your webapp push something to a queue that a continuously running console app would consume at the next suitable opportunity
beanstalkd - only found this one while writing this answer, but looks interesting
dropr is a PHP based message queue project, but hasn't been actively maintained since Sep 2010
php-enqueue is a recently (2017) maintained wrapper around a variety of queue systems
Finally, a blog post about using memcached for message queuing
Another, perhaps simpler, approach is to use ignore_user_abort - once you've sent the page to the user, you can do your final processing without fear of premature termination, though this does have the effect of appearing to prolong the page load from the user perspective.
When you just want to execute one or several HTTP requests without having to wait for the response, there is a simple PHP solution, as well.
In the calling script:
$socketcon = fsockopen($host, 80, $errno, $errstr, 10);
if($socketcon) {
$socketdata = "GET $remote_house/script.php?parameters=... HTTP 1.1\r\nHost: $host\r\nConnection: Close\r\n\r\n";
fwrite($socketcon, $socketdata);
fclose($socketcon);
}
// repeat this with different parameters as often as you like
On the called script.php, you can invoke these PHP functions in the first lines:
ignore_user_abort(true);
set_time_limit(0);
This causes the script to continue running without time limit when the HTTP connection is closed.
Another way to fork processes is via curl. You can set up your internal tasks as a webservice. For example:
http://domain/tasks/t1
http://domain/tasks/t2
Then in your user accessed scripts make calls to the service:
$service->addTask('t1', $data); // post data to URL via curl
Your service can keep track of the queue of tasks with mysql or whatever you like the point is: it's all wrapped up within the service and your script is just consuming URLs. This frees you up to move the service to another machine/server if necessary (ie easily scalable).
Adding http authorization or a custom authorization scheme (like Amazon's web services) lets you open up your tasks to be consumed by other people/services (if you want) and you could take it further and add a monitoring service on top to keep track of queue and task status.
http://domain/queue?task=t1
http://domain/queue?task=t2
http://domain/queue/t1/100931
It does take a bit of set-up work but there are a lot of benefits.
If it just a question of providing expensive tasks, in case of php-fpm is supported, why not to use fastcgi_finish_request() function?
This function flushes all response data to the client and finishes the request. This allows for time consuming tasks to be performed without leaving the connection to the client open.
You don't really use asynchronicity in this way:
Make all your main code first.
Execute fastcgi_finish_request().
Make all heavy stuff.
Once again php-fpm is needed.
I've used Beanstalkd for one project, and planned to again. I've found it to be an excellent way to run asynchronous processes.
A couple of things I've done with it are:
Image resizing - and with a lightly loaded queue passing off to a CLI-based PHP script, resizing large (2mb+) images worked just fine, but trying to resize the same images within a mod_php instance was regularly running into memory-space issues (I limited the PHP process to 32MB, and the resizing took more than that)
near-future checks - beanstalkd has delays available to it (make this job available to run only after X seconds) - so I can fire off 5 or 10 checks for an event, a little later in time
I wrote a Zend-Framework based system to decode a 'nice' url, so for example, to resize an image it would call QueueTask('/image/resize/filename/example.jpg'). The URL was first decoded to an array(module,controller,action,parameters), and then converted to JSON for injection to the queue itself.
A long running cli script then picked up the job from the queue, ran it (via Zend_Router_Simple), and if required, put information into memcached for the website PHP to pick up as required when it was done.
One wrinkle I did also put in was that the cli-script only ran for 50 loops before restarting, but if it did want to restart as planned, it would do so immediately (being run via a bash-script). If there was a problem and I did exit(0) (the default value for exit; or die();) it would first pause for a couple of seconds.
Here is a simple class I coded for my web application. It allows for forking PHP scripts and other scripts. Works on UNIX and Windows.
class BackgroundProcess {
static function open($exec, $cwd = null) {
if (!is_string($cwd)) {
$cwd = #getcwd();
}
#chdir($cwd);
if (strtoupper(substr(PHP_OS, 0, 3)) == 'WIN') {
$WshShell = new COM("WScript.Shell");
$WshShell->CurrentDirectory = str_replace('/', '\\', $cwd);
$WshShell->Run($exec, 0, false);
} else {
exec($exec . " > /dev/null 2>&1 &");
}
}
static function fork($phpScript, $phpExec = null) {
$cwd = dirname($phpScript);
#putenv("PHP_FORCECLI=true");
if (!is_string($phpExec) || !file_exists($phpExec)) {
if (strtoupper(substr(PHP_OS, 0, 3)) == 'WIN') {
$phpExec = str_replace('/', '\\', dirname(ini_get('extension_dir'))) . '\php.exe';
if (#file_exists($phpExec)) {
BackgroundProcess::open(escapeshellarg($phpExec) . " " . escapeshellarg($phpScript), $cwd);
}
} else {
$phpExec = exec("which php-cli");
if ($phpExec[0] != '/') {
$phpExec = exec("which php");
}
if ($phpExec[0] == '/') {
BackgroundProcess::open(escapeshellarg($phpExec) . " " . escapeshellarg($phpScript), $cwd);
}
}
} else {
if (strtoupper(substr(PHP_OS, 0, 3)) == 'WIN') {
$phpExec = str_replace('/', '\\', $phpExec);
}
BackgroundProcess::open(escapeshellarg($phpExec) . " " . escapeshellarg($phpScript), $cwd);
}
}
}
PHP HAS multithreading, its just not enabled by default, there is an extension called pthreads which does exactly that.
You'll need php compiled with ZTS though. (Thread Safe)
Links:
Examples
Another tutorial
pthreads PECL Extension
UPDATE: since PHP 7.2 parallel extension comes into play
Tutorial/Example
reference manual
This is the same method I have been using for a couple of years now and I haven't seen or found anything better. As people have said, PHP is single threaded, so there isn't much else you can do.
I have actually added one extra level to this and that's getting and storing the process id. This allows me to redirect to another page and have the user sit on that page, using AJAX to check if the process is complete (process id no longer exists). This is useful for cases where the length of the script would cause the browser to timeout, but the user needs to wait for that script to complete before the next step. (In my case it was processing large ZIP files with CSV like files that add up to 30 000 records to the database after which the user needs to confirm some information.)
I have also used a similar process for report generation. I'm not sure I'd use "background processing" for something such as an email, unless there is a real problem with a slow SMTP. Instead I might use a table as a queue and then have a process that runs every minute to send the emails within the queue. You would need to be warry of sending emails twice or other similar problems. I would consider a similar queueing process for other tasks as well.
It's a great idea to use cURL as suggested by rojoca.
Here is an example. You can monitor text.txt while the script is running in background:
<?php
function doCurl($begin)
{
echo "Do curl<br />\n";
$url = 'http://'.$_SERVER['SERVER_NAME'].$_SERVER['REQUEST_URI'];
$url = preg_replace('/\?.*/', '', $url);
$url .= '?begin='.$begin;
echo 'URL: '.$url.'<br>';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$result = curl_exec($ch);
echo 'Result: '.$result.'<br>';
curl_close($ch);
}
if (empty($_GET['begin'])) {
doCurl(1);
}
else {
while (ob_get_level())
ob_end_clean();
header('Connection: close');
ignore_user_abort();
ob_start();
echo 'Connection Closed';
$size = ob_get_length();
header("Content-Length: $size");
ob_end_flush();
flush();
$begin = $_GET['begin'];
$fp = fopen("text.txt", "w");
fprintf($fp, "begin: %d\n", $begin);
for ($i = 0; $i < 15; $i++) {
sleep(1);
fprintf($fp, "i: %d\n", $i);
}
fclose($fp);
if ($begin < 10)
doCurl($begin + 1);
}
?>
There is a PHP extension, called Swoole.
Although it might not be enabled, it is available on my hosting for being enabled at click of a button.
Worth checking it out. I haven't had time to use it yet, as I was searching here for info, when I stumbled across it and thought it worth sharing.
Unfortunately PHP does not have any kind of native threading capabilities. So I think in this case you have no choice but to use some kind of custom code to do what you want to do.
If you search around the net for PHP threading stuff, some people have come up with ways to simulate threads on PHP.
If you set the Content-Length HTTP header in your "Thank You For Registering" response, then the browser should close the connection after the specified number of bytes are received. This leaves the server side process running (assuming that ignore_user_abort is set) so it can finish working without making the end user wait.
Of course you will need to calculate the size of your response content before rendering the headers, but that's pretty easy for short responses (write output to a string, call strlen(), call header(), render string).
This approach has the advantage of not forcing you to manage a "front end" queue, and although you may need to do some work on the back end to prevent racing HTTP child processes from stepping on each other, that's something you needed to do already, anyway.
If you don't want the full blown ActiveMQ, I recommend to consider RabbitMQ. RabbitMQ is lightweight messaging that uses the AMQP standard.
I recommend to also look into php-amqplib - a popular AMQP client library to access AMQP based message brokers.
Spawning new processes on the server using exec() or directly on another server using curl doesn't scale all that well at all, if we go for exec you are basically filling your server with long running processes which can be handled by other non web facing servers, and using curl ties up another server unless you build in some sort of load balancing.
I have used Gearman in a few situations and I find it better for this sort of use case. I can use a single job queue server to basically handle queuing of all the jobs needing to be done by the server and spin up worker servers, each of which can run as many instances of the worker process as needed, and scale up the number of worker servers as needed and spin them down when not needed. It also let's me shut down the worker processes entirely when needed and queues the jobs up until the workers come back online.
i think you should try this technique it will help to call as many as pages you like all pages will run at once independently without waiting for each page response as asynchronous.
cornjobpage.php //mainpage
<?php
post_async("http://localhost/projectname/testpage.php", "Keywordname=testValue");
//post_async("http://localhost/projectname/testpage.php", "Keywordname=testValue2");
//post_async("http://localhost/projectname/otherpage.php", "Keywordname=anyValue");
//call as many as pages you like all pages will run at once independently without waiting for each page response as asynchronous.
?>
<?php
/*
* Executes a PHP page asynchronously so the current page does not have to wait for it to finish running.
*
*/
function post_async($url,$params)
{
$post_string = $params;
$parts=parse_url($url);
$fp = fsockopen($parts['host'],
isset($parts['port'])?$parts['port']:80,
$errno, $errstr, 30);
$out = "GET ".$parts['path']."?$post_string"." HTTP/1.1\r\n";//you can use POST instead of GET if you like
$out.= "Host: ".$parts['host']."\r\n";
$out.= "Content-Type: application/x-www-form-urlencoded\r\n";
$out.= "Content-Length: ".strlen($post_string)."\r\n";
$out.= "Connection: Close\r\n\r\n";
fwrite($fp, $out);
fclose($fp);
}
?>
testpage.php
<?
echo $_REQUEST["Keywordname"];//case1 Output > testValue
?>
PS:if you want to send url parameters as loop then follow this answer :https://stackoverflow.com/a/41225209/6295712
PHP is a single-threaded language, so there is no official way to start an asynchronous process with it other than using exec or popen. There is a blog post about that here. Your idea for a queue in MySQL is a good idea as well.
Your specific requirement here is for sending an email to the user. I'm curious as to why you are trying to do that asynchronously since sending an email is a pretty trivial and quick task to perform. I suppose if you are sending tons of email and your ISP is blocking you on suspicion of spamming, that might be one reason to queue, but other than that I can't think of any reason to do it this way.