i need to load data as array to memory in PHP.but in PHP if i write $array= array("1","2"); in test.php then this $array variable
is initialized every time user requests.if we request test.php 100 times by clicking 100 times browser refresh button then this $array variable will be executed 100 times.
but i need to execute the $array variable only one time for first time request and subsequent request of test.php must not execute the $array variable.but only use that memory location.how can i do that in PHP.
but in JAVA SEVRVLET it is easy to execute,just write the $array variable in one time execution of init() method of servlet lifecycle method and subsequent request of that servlet dont execute init() method but service() method but service() method always uses
that $array memeory location.
all i want to initilize $array variable once but use that memory loc from subsequent request in PHP.is there any possiblity in PHP?
PHP works differently than a Java Servlet container. Every new request basically starts an entirely new instance of the PHP interpreter, therefore you don't have a global adress space across requests (you do have a session per user which gets usually persisted to a file to keep variables across requests for one user).
A thing that might come close to it would be to use memcached with PHP as your "database", but you will have to send a request to the memcached server every time you need your array. That is why I think your array (if it doesn't change) is best kept and initialized in the PHP file.
use session
start the session when user opens test.php and set the array in that session
<?php
session_start();
if(!isset($_SESSION['user_action'])){
$_SESSION['user_action'] = array("1","2");
}
?>
That code will just verify if the session variable "user_action" is set, if it isn't then it will set with that array.
Then you can change that variable later.
All variables are destroyed at request shutdown, there is no built-in mechanism to do what you want in php.
PHP has different kind of execution.
In general, it's impossible in PHP and it's OK.
You can try the following:
<?php
/* test.php */
if (empty($GLOBALS['array'])) {
$GLOBALS['array'] = array("1", "2");
}
?>
Related
I'm running IIS on a Windows Server w/PHP 5.3. I have two scripts; let's call them initiator.php and worker.php. A user calls initiator.php and in this script a variable is defined; let's call it $input. I would like to take this $input variable and pass it to worker.php like so:
$oShell = new COM('Wscript.Shell');
$oShell->Run("\"C:/Program Files (x86)/PHP/v5.3/php/worker.php -a $input",0,False);
In worker.php I have the following to pick up the $input variable passed from initiator.php.
$aCliOpts = getopt('a:');
$input_from_initiator = $aCliOpts['a'];
This works great. initiator.php's $input variable is successfully passed to worker.php which picks it up and initiator.php keeps chugging. However, worker.php then takes it's own $input_from_initiator variable, runs through some quick code of it's own and creates a third variable called $output_from_worker. It is this variable that I need initiator.php to read a little ways into it's processing. This is where I'm getting hung up.
I've tried passing the variable back to initiator.php from worker.php the same way it a variable as passed in the beginning and this did not work. I've also tried to use:
header('Location: initiator.php?var=value')
using HTTP GET params but to no avail.
My last resort is for worker.php to write this variable's value to disk then have initiator.php read from disk. I hate to do this due to the latent disk I/O. Speed is very important to this script.
Is there a way two PHP processes can pass variables between each other in memory?
Have a look at file_get_contents() http://php.net/file_get_contents, which you can pass a URL to. So you could use the Query String like:
$var = file_get_contents('http://site.tld/worker.php?input='.$input);
And in worker.php, simply echo your result.
It's a shame you're running on Windows, because the sys5 extension on *nix is marvelous!
You can always use files or a database etc for communication.
Thanks for the help although I ended up doing something a little different than my original question. I was trying to run different cURL requests. curl_multi_exec() ended up working great for me.
I have a JavaScript functions which calls a PHP function through AJAX.
The PHP function has a set_time_limit(0) for its purposes.
Is there any way to stop that function when I want, for example with an HTML button event?
I want to explain better the situation:
I have a php file which uses a stream_copy_to_stream($src, $dest) php function to retrieve a stream in my local network. The function has to work until I want: I can stop it at the end of the stream or when I want. So I can use a button to start and a button to stop. The problem is the new instance created by the ajax call, in fact I can't work on it because it is not the function that is recording but it is another instance. I tried MireSVK's suggest but it doesn't worked!
Depending on the function. If it is a while loop checking for certain condition every time, then you could add a condition that is modifiable from outside the script (e.g. make it check for a file, and create / delete that file as required)
It looks like a bad idea, however. Why you want to do it?
var running = true;
function doSomething(){
//do something........
}
setInterval(function(){if(running){doSomething()}},2000); ///this runs do something every 2 seconds
on button click simply set running = false;
Your code looks like:
set_time_limit(0);
while(true==true){//infinite loop
doSomething(); //your code
}
Let's upgrade it
set_time_limit(0);
session_start();
$_SESSION['do_a_loop'] = true;
function should_i_stop_loop(){
#session_start();
if( $_SESSION['do_a_loop'] == false ) {
//let's stop a loop
exit();
}
session_write_close();
}
while(true==true){
doSomething();
should_i_stop_loop(); //your new function
}
Create new file stopit.php
session_start();
$_SESSION['do_a_loop'] = false;
All you have to do now is create a request on stopit.php file (with ajax or something)
Edit code according to your needs, this is point. One of many solutions.
Sorry for my English
Sadly this isn't possible (sort of).
Each time you make an AJAX call to a PHP script the script spawns a new instance of itself. Thus anything you send to it will be sent to a new operation, not the operation you had previously started.
There are a number of workarounds.
Use readystate 3 in AJAX to create a non closing connection to the PHP script, however that isn't supported cross browser and probably won't work in IE (not sure about IE 10).
Look into socket programming in PHP, which allows you to create a script with one instance that you can connect to multiple times.
Have PHP check a third party. I.E have one script running in a loop checking a file or a database, then connect to another script to modify that file or database. The original script can be remotely controlled by what you write to the file/database.
Try another programming language (this is a silly option, but I'm a fan of node). Node.js does this sort of thing very very easily.
Is there a way to prevent a code-block or a function within a code from running more than once even if I re-execute (or reload) the PHP file?
I mean, can I restrict someone from executing a php script more than once? I can't seem to find the way to do this.
Yes, you can use a $_SESSION variable to determine if the code has been executed. The session variable will be set until the user closes their browser. If you want to extend it further than that, you can set a cookie. Please see the following links for more details.
Session Variables
Cookies
If you are using sessions, then you can set a flag in the user's session array after the code has executed:
function doSomething(){
if (empty($_SESSION['completed'])){
//Do stuff here if it has not been executed.
}
$_SESSION['completed'] = TRUE;
}
You should also check the sesison variable to see if the task has been executed previously. This assumes that the user can accept a session cookie.
I have an app that does that.
What we did was create a table in the db called version, and stored a version number in there. When the script is ran, it compared the version number in the database with that in the php script. And perform whatever it needs to "upgrade" it to the new version, and then updates the version number in the database.
Of couse, if the version table does not exist, the code will create it and mark it as storing version zero.
Just put a counter in the function. If the counter is greater that 0, then don't do anything. The counter variable should be static so it "remembered" across multiple calls.
function sample() {
static $call_counter = 0;
if ( $call_counter>0 ) {
return;
}
...
$call_counter++;
}
As for making sure a file is only executed once, just use "include_once()" instead of "include()".
I have a counter timer and I tried to block a simple bypass to download without waiting.
so in main class I declared the boolean
$allow_download = false;
and in Javascript when the time is elapsed
else
{
textDLShow.style.display = 'none';
divDLShow.style.display = '';
"<?php $allow_download = true;?>";
}
and in the second class
if($allow_download == false)
echo "Test";
well, when time is elapsed the boolean is not set with positive value. Any suggestions ??
Thanks for your time !!
JavaScript cannot set the value of a PHP variable since the JavaScript interpreter cannot parse PHP (nor is the variable in the same interpreter anyway, since the JavaScript is run on the client's browser rather than on the server.)
In order to do this you will need to make a new request with JavaScript that your PHP code can read in order to set $allow_download to true and then serve up the download.
You'll want to read up on ajax, document.createElement (because one way to do this might be to create an iframe pointing at the download location after the time has elapsed) and setTimeout.
PHP is run on your server, the variables you create are no longer in scope when your client side javascript runs. There is no way to fix this unless you want to cook up some heavier stuff like storing in a database which IP addresses can download which files at what time.
php can run javascript, but javascript can never run php, take it for granted
the best thing you can do is run an ajax script to kind of call the php on the background
but really why bother going with all that, you can include the javascript in a php function and let it do the job
i have a php script that accepts a POST request as a listener to a web service then process all the data to two final arrays,
I'm looking for a way to initiate a second script that GET's those serialized arrays and do some more processing.
include() will not be good for me since i actually want to "free" or "end" the first script after passing the data
your help is much appreciated as always :)
EDIT - OK so looks like queue might be the solution! i never did anything like this before any examples or reference?
Does it need to happen immediately? Otherwise you could set up a cronjob that does that every X minutes. You'll have to make some kind of queue in which your first script sticks "requests" to the second script. The cronjob then processes the requests in the queue.
You should get into the habit of writing php scripts that are just a collection of functions (no auto-ran scripts, per se). This way you can include a script file at the top of the script your talking about and then call the function that does what you want.
For instance:
<?php
include('common_functions.php');
$array_1 = whatever_you_do_with_post_values();
$array_2 = other_thing_you_do_with_post_values();
// this function is located in 'common_functions.php'
do_stuff_with_arrays($array_1,$array_2);
?>
In Fact:
Just to be consistent with what I'm saying:
<?php
include('common_functions.php');
do_your_stuff();
function do_your_stuff() {
$array_1 = whatever_you_do_with_post_values();
$array_2 = other_thing_you_do_with_post_values();
// this function is located in 'common_functions.php'
do_stuff_with_arrays($array_1,$array_2);
}
?>
Obviously you should use better function & variable names, haha.
I'd do it all in one request. It cuts down on latency and makes the whole operation more efficient.
Remember you can have a long running request, but still service other requests. Apache will just spawn another php process to handle the other request from the webservice even though the first has not completed. As long as the script doesn't lock a shared resource (database file etc) this will work just fine.
That said, you should use cURL to call the second script. then post the unserialized array. cUrl will handle the rest.