I am working on a TYPO3 project where I have to dynamically disable caching based on a condition. It is a very specific usecase, that will not happen a lot.
I planned to use a USER_INT function, where I would perform the check and disable the cache if necessary. The USER_INT function works flawlessly, it is being called on every page load.
The thing is, I can not disable the cache, or at least I do not know how.
The code, I have right now:
page = PAGE
page {
typeNum = 0
adminPanelStyles = 0
11 = USER_INT
11.userFunc = [COMPANY_NAMESPACE]\PageHandler->checkCache
And in the function I perform the check:
public function checkCache($content,$conf){
global $TSFE;
$id = $TSFE->id;
if($this->checkIfDisableCache($id)){
//$TSFE->set_no_cache(); // <---- first I tried this one
$TSFE->no_cache=true; // <-----after a while I got despoerate and tried to disable it directly
}
}
I also tried to play with the config, it did not work.
The funny thing is, if I set it directly in typoscript:
config.no_cache = 1
it works, but since the check is rather complex, I want to use PHP to determine, if the cache should be disabled.
I know I am doing something wrong, I just don't know what. Any help would be appretiated :)
I don't think either of the previous answers really explain the situation. You have sort of a catch-22 here, in that your USER_INT is executed after the page cache entry has been generated. The way it works internally is everything that can be cached gets rendered first, and every USER_INT then outputs a marker in the HTML source which gets replaced afterwards. This way the cache can contain the version with markers and those can be rendered without having to render the whole page.
So what you need to do in this case if you want the page cache to be disabled only in some conditions, is to use a custom TypoScript condition that is capable of setting config.no_cache = 1 only under special circumstances. That way you prevent generating a cache entry if the condition is met, but preserve full caching and cached output for every other request.
https://docs.typo3.org/typo3cms/TyposcriptSyntaxReference/TypoScriptParserApi/CustomConditions/Index.html
Note that it is still recommended that you instead create the parts of your page that must not be cached, as USER_INT objects. Having a use case where you in some cases need to disable the entire page cache indicates a possible misunderstanding of how the caching framework and/or USER_INT works. Hopefully the above explains those parts a bit.
if you look at the pibase (AbstractPlugin) code you will see that probably setting $conf['useCacheHash']and $conf['no_cache'] should be done.
https://api.typo3.org/typo3cms/current/html/_abstract_plugin_8php_source.html#l00190
If you create this object as USER_INT, it will be rendered non-cached, outside the main page-rendering.
https://docs.typo3.org/typo3cms/TyposcriptReference/ContentObjects/UserAndUserInt/Index.html
Related
I have a PHP script that can take a few minutes to be done. It's some search engine which executes a bunch of regex commands and retrieve the results to the user.
I start by displaying a "loading page" which does an AJAX call to the big processing method in my controller (let's call it 'P'). This method then returns a partial view and I just replace my "loading page" content with that partial view. It works fine.
Now what I would like to do is give the user some information about the process (and later on, some control over it), like how many results the script has already found. To achieve that, I do another AJAX call every 5 seconds which is supposed to retrieve the current number of results and display it in a simple html element. This call uses a method 'R' in the same controller as method 'P'.
Now the problem I have is that I'm not able to retrieve the correct current number of results. I tried 2 things :
Session variable ('file' driver) : in 'P' I first set a session variable 'v' to 0 and then update 'v' every time a new result is found. 'R' simply returns response()->json(session('v'))
Controller variable : same principle as above but I use a variable declared at the top of my controller.
The AJAX call to 'P' works in both cases, but everytime and in both cases it returns 0. If I send back 'v' at the end of the 'P' script, it has the correct value.
So to me it looks like 'R' can't access the actual current value of 'v', it only access some 'cached' version of it.
Does anyone have an idea about how I'm going to be able to achieve what I'd like to do? Is there another "cleaner" approach and/or what is wrong with mine?
Thank you, have a nice day!
__
Some pseudo-code to hopefully make it a bit more precise.
SearchController.php
function P() {
$i = 0;
session(['count' => $i]); // set session variable
$results = sqlQuery(); // get rows from DB
foreach ($results as $result) {
if (regexFunction($result))
$i++
session(['count' => $i]); // update session variable
}
return response()->json('a bunch of stuff');
}
function R() {
return response()->json(session('count')); // always returns 0
}
I would recommend a different approach here.
Read a bit more about flushing content here http://php.net/manual/en/ref.outcontrol.php and then use it.
Long story short in order to display the numbers of row processed with flushing you could just make a loop result and flush from time to time or at an exact number or rows, the need for the 5 seconds AJAX is gone. Small untested example :
$cnt = 0;
foreach($result as $key => $val) {
//do your processing here
if ($cnt % 100 == 0) {
//here echo smth for flushing, you can echo some javascript, tough not nice
echo "<script>showProcess({$cnt});</script>";
ob_flush();
}
}
// now render the proccessed full result
And in the showProcess javascript function make what you want... some jquery replace in a text or some graphical stuff...
Hopefully u are not using fast_cgi, beacause in order to activate output buffering you need to disable some important features.
I believe you have hit a wall with PHP limitations. PHP doesn't multithread, well. To achieve the level of interaction you are probably required to edit the session files directly, the path of which can be found in your session.save_path global through php_info(), and you can edit this path with session_save_path(String). Though this isn't recommended usage, do so at your own risk.
Alternatively use a JSON TXT file stored somewhere on your computer/server, identifying them in a similar manner to the session files.
You should store the current progress of the query to a file and also if the transaction has been interrupted by the user. a check should be performed on the status of the interrupt bit/boolean before continuing to iterate over the result set.
The issue arises when you consider concurrency, what if the boolean is edited just slightly before, or at the same time, as the count array? Perhaps you just keep updating the file with interrupts until the other script gets the message. This however is not an elegant solution.
Nor does this solution allow for concurrent queries being run by the same user. to counter this an additional check should be performed on the session file to determine if something is already running. An error should be flagged to notify the user.
Given the option, I would personally, rewrite the code in either JSP or ASP.NET
All in all this is a lot of work for an unreliable feature.
My scripts run if I do:
$config['max'] = 20;
It doesn't run if I use the configuration-value of my plugin like
$config['max'] = get_option('plugin_max');
Also not like
$config['max'] = intval(get_option('plugin_max'));
In every case, if I print $config['max'], it prints
20
I think there must be some stupid datatype-mismatch, but I can't figure out what it could be.
Solution
ok, I have to clear this up and maybe it will help someone later on. The problem was that get_option was undefined because it was called directly in an AJAX-request. I now routed the ajax-requests properly over WPs admin-ajax.php function so that WP-functions are available to the plugin even when called from AJAX.
Strangely, while debugging, the function was available, but this might have been while initialising the plugin, which is of course no AJAX-request but entirely server-side and so inside the scope of WP by default.
Thanks for your support!
I need a code to cache just part of the page, in fact i want to cache the result of a function.
Example :
CODE HTML
<? my php code ?> <!- I want to cache this only -->
CODE HTML
I found a few incomplete codes but functions are missing and it's not working.
Thanks.
I assume you mean server-side caching for a function that takes awhile to run but has the same output for many users.
If so, check out Memcached. http://memcached.org/
http://php.net/manual/en/book.memcached.php
Hash the parameters for your function, use that as a key. Then stick the result in memcached and check for it the next time that function is called.
I'm having a multiplayer server that's using PHPSockets, and thus is written entirely in PHP.
Currently, whenever I'm making any changes to the PHP server-script I have to kill the script and then start it over again. This means that any users online is disconnected (normally not a problem because there aren't so many at the moment).
Now I am rewriting the server-script to use custom PHP classes and sorten things up a little bit (you don't want to know how nasty it looks today). Today I was thinking: "Shouldn't it be possible to make changes to the php source without having to restart the whole script?".
For example, I'm planning on having a main.php file that is including user.php which contains the class MyUser and game.php which contains the class MyGame. Now let's say that I would like to make a change to user.php and "reload" the server so that the changes to user.php goes into effect, without disconnecting any online users?
I tried to find other questions that answered this, the closest I got is this question: Modifying a running script and having it reload without killing it (php) , which however doesn't seem to solve the disconnection of online users.
UPDATE
My own solutions to this were:
At special occations, include the file external.php, which can access a few variables and use them however it'd like. When doing this, I had to make sure that there were no errors in the code as the whole server would crash if I tried accessing a method that did not exist.
Rewrite the whole thing to Java, which gave me the possibility of adding a plugin system using dynamic class reloading. Works like a charm. Bye bye PHP.
Shouldn't it be possible to make changes to the php source without having to restart the whole script?
[...]
I'm planning on having a main.php file that is including user.php
which contains the class MyUser
In your case, you can't. Classes can only be defined once within a running script. You would need to restart the script to have those classes redefined.
I am not too familiar with PHP but I would assume that a process is created to run the script, in doing so it copies the instructions needed to run the program and begins execution on the CPU, during this, if you were to "update" the instructions, you'd need to kill the process ultimate and restart it. Includes are a fancy way of linking your classes and files together but ultimately the processor will have that information separate from where the file of them are stored and it is ultimately different until you restart the process.
I do not know of any system in which you can create code and actively edit it and see the changes while that code is being run. Most active programs require restart to reload new source code.
Runkit will allow you to add, remove, and redefine methods (among other things) at runtime. While you cannot change the defined properties of a class or its existing instances, it would allow you to change the behavior of those objects.
I don't recommend this as a permanent solution, but it might be useful during development. Eventually you'll want to store the game state to files, a database, Memcache, etc.
How about storing your User object into APC cache while your main script loads from the cache and checks every so often for new opcode.
To include a function in the cache, you must include the SuperClosure Class. An example would be:
if (!apc_exists('area')) {
// simple closure
// calculates area given length and width
$area = new SuperClosure(
function($length, $width) {
return $length * $width;
}
);
apc_store('area', $area);
echo 'Added closure to cache.';
} else {
$func = apc_fetch('area');
echo 'Retrieved closure from cache. ';
echo 'The area of a 6x5 polygon is: ' . $func(6,5);
}
See here for a tutorial on APC.
Simple solution use $MyUser instead of MyUser
require MyUserV1.php;
$MyUser = 'MyUserV1';
$oldUser = new $MyUser('your name');
//Some time after
require MyUserV2.php;
$MyUser = 'MyUserV2';
$newUser = new $MyUser('your name');
Every declared class stay in memory but become unused when the last MyUserV1 logout
you can make them inherit from an abstract class MyUser for using is_a
You cannot include again a file with the same class, but you can do so with an array. You can also convert from array to class, if you really need to do so. This only applies to data, though, not to behavior (methods).
I don't know much about these things with the games on PC but you can try to get all the variables from your database for the user and then update the text fields or buttons using those variables
In web is using AJAX (change data without refreshing the page).Isn't one for programming?
I'm trying to display some content in real time to my visitors using a loop. Problem is that the content is added to the output instead of being replaced with the new one. Here's an example of code which counts from 10 to 0. The output shows the whole set of results instead of counting backwards. I mean, I don't want to see all numbers shown just each number as the counter goes.
ob_end_flush ();
//start buffering
ob_start ();
echo str_pad ( '', 1024 ); // minimum start for Safari
for ( $i = 10; $i > 0; $i --) {
echo str_pad ( "$i<br>\n", 8 );
ob_flush ();
flush ();
sleep ( 1 );
}
die ();
This can not be achieved with PHP alone, as to alter what is rendered in the browser requires some client side intervention.
How you go about this division of labour depends upon what is needed.
If your code is all of it, then you would be far better off writing a JS routine to count down the numbers in a timed fashion.
If PHP is required in some other fashion to generate the numbers then the decision needs to be taken as to whether you can split the generation of the update in to multiple PHP calls or if it has to be from within the single PHP call due to actions taking forth within that call.
If the former, you can separate it, which is the ideal situation - then the procedure is to setup AJAX calls to retrieve updated information periodically.
If the latter and it must be from a single page, then the connection must be kept open with new content generated.
In this case, to get new content to replace old, JS code must handle this. Either code running periodically upon the page can check for new content and update accordingly, or a little trick can be played injecting code that performs the update.
Sending inline <script> content that performs the update instead of new display elements works well, if a little untidy, as the browser receives the new <script> element it is run. This is the only way I am aware of that a push-update can be made to a web page without plugins.
There might be a trick or something (just thought of one or two) but the most appropriate way to do it is with an ajax autoupdate from the browser. Like this pattern description.
We didnt do this in PHP, in fact using js. ( with Stacker help ) you can reverse the count
But am sure you could adopt, sorry if this doesnt answer your question.
Demo here on our dev site < link >
You can also ( again may not be pertinent, use jquery to refresh a div element )