array_push overwritting array data [duplicate] - php

Is there a way in PHP to use "out of session" variables, which would not be loaded/unloaded at every connexion, like in a Java server ?
Please excuse me for the lack of accuracy, I don't figure out how to write it in a proper way.
The main idea would be to have something like this :
<?php
...
// $variablesAlreadyLoaded is kind of "static" and shared between all PHP threads
// No need to initialize/load/instantiate it.
$myVar = $variablesAlreadyLoaded['aConstantValueForEveryone'];
...
?>
I already did things like this using shmop and other weird things, but if there is a "clean" way to do this in "pure PHP" without using caching systems (I think about APC, Redis...), nor database.
EDIT 1 :
Since people (thanks to them having spent time for me) are answering me the same way with sessions, I add a constraint I missed to write : no sessions please.
EDIT 2 :
It seems the only PHP native methods to do such a thing are shared memory (shmop) and named pipes. I would use a managed manner to access shared objects, with no mind of memory management (shared memory block size) nor system problems (pipes).
Then, I browsed the net for a PHP module/library which provides functions/methods to do that : I found nothing.
EDIT 3 :
After a few researches on the way pointed out by #KFO, it appears that the putenv / setenv are not made to deal with objects (and I would avoid serialization). Thus, it resolves the problem for short "things" such as strings or numbers but not for more large/comples objects.
Using the "env way" AND another method to deal with bigger objects would be uncoherent and add complexity to the code and maintenability.
EDIT 4 :
Found this : DBus (GREE Lab DBus), but I'm not having tools to test it at work. Has somebody tested it yet ?
I'm open to every suggestion.
Thanks
EDIT 5 ("ANSWER"):
Since DBus is not exactly what I'm looking for (needs to install a third-party module, with no "serious" application evidence), I'm now using Memcache which has already proven its reliability (following #PeterM comment, see below).

// First page
session_id('same_session_id_for_all');
session_start();
$_SESSION['aConstantValueForEveryone'] = 'My Content';
// Second page
session_id('same_session_id_for_all');
session_start();
echo $_SESSION['aConstantValueForEveryone'];
This works out of the box in PHP. Using the same session id (instead of an random user-uniqe string) to initialize the session for all visitors leads to a session which is the same for all users.
Is it really necessary to use session to achieve the goal or wouldn't it better to use constants?
There is no pure PHP way of sharing information across different
threads in PHP! Except for an "external"
file/database/servervariable/sessionfile solution.
Since some commentators pointed out, that there is serialize/unserialize functionality for Session data which might break data on the transport, there is a solution: In PHP the serialize and unserialize functionality serialize_handler can be configured as needed. See https://www.php.net/manual/session.configuration.php#ini.session.serialize-handler It might be also interesting to have a look at the magic class methods __sleep() and __wakeup() they define how a object behaves on a serialize or unserialize request. https://www.php.net/manual/language.oop5.magic.php#object.sleep ... Since PHP 5.1 there is also a predefined Serializable interface available: https://www.php.net/manual/class.serializable.php

You can declare a Variable in your .htaccess. For Example SetEnv APPLICATION_ENVIRONMENT production and access it in your application with the function getenv('APPLICATION_ENVIRONMENT')

Another solution is to wrap your variable in a "persistent data" class that will automatically restore its data content every time the php script is run.
Your class needs to to the following:
store content of variable into file in __destructor
load content of variable from file in __constructor
I prefer storing the file in JSON format so the content can be easily examined for debugging, but that is optional.
Be aware that some webservers will change the current working directory in the destructor, so you need to work with an absolute path.

I think you can use $_SESSION['aConstantValueForEveryone'] that you can read it on every page on same domain.
Consider to refer to it's manual.

Related

Should I store application-scope variable inside a file in PHP?

I want store a variable shared between sessions (application-scope):
It is not user session-specific (so I can't put it in $_SESSION[]).
It is a long term storage (so I can't use APC - Alternative PHP Cache).
So, I use a file do store the variable and access it using file_get_contents and file_put_contents functions.
Is it a good way of proceeding or is there any alternative?
It's clear your's is a global, server side issue. I would use a Database to do it. Just CRUD when needed.
You'rs may do the work, but I recommend the database approach, due to the enhanced capabilities that it provides like logging, checking the history of events. I think is a cleaner solution.

Is there a way in PHP to use persistent data as in Java EE? (sharing objects between PHP threads) without session nor cache/DB

Is there a way in PHP to use "out of session" variables, which would not be loaded/unloaded at every connexion, like in a Java server ?
Please excuse me for the lack of accuracy, I don't figure out how to write it in a proper way.
The main idea would be to have something like this :
<?php
...
// $variablesAlreadyLoaded is kind of "static" and shared between all PHP threads
// No need to initialize/load/instantiate it.
$myVar = $variablesAlreadyLoaded['aConstantValueForEveryone'];
...
?>
I already did things like this using shmop and other weird things, but if there is a "clean" way to do this in "pure PHP" without using caching systems (I think about APC, Redis...), nor database.
EDIT 1 :
Since people (thanks to them having spent time for me) are answering me the same way with sessions, I add a constraint I missed to write : no sessions please.
EDIT 2 :
It seems the only PHP native methods to do such a thing are shared memory (shmop) and named pipes. I would use a managed manner to access shared objects, with no mind of memory management (shared memory block size) nor system problems (pipes).
Then, I browsed the net for a PHP module/library which provides functions/methods to do that : I found nothing.
EDIT 3 :
After a few researches on the way pointed out by #KFO, it appears that the putenv / setenv are not made to deal with objects (and I would avoid serialization). Thus, it resolves the problem for short "things" such as strings or numbers but not for more large/comples objects.
Using the "env way" AND another method to deal with bigger objects would be uncoherent and add complexity to the code and maintenability.
EDIT 4 :
Found this : DBus (GREE Lab DBus), but I'm not having tools to test it at work. Has somebody tested it yet ?
I'm open to every suggestion.
Thanks
EDIT 5 ("ANSWER"):
Since DBus is not exactly what I'm looking for (needs to install a third-party module, with no "serious" application evidence), I'm now using Memcache which has already proven its reliability (following #PeterM comment, see below).
// First page
session_id('same_session_id_for_all');
session_start();
$_SESSION['aConstantValueForEveryone'] = 'My Content';
// Second page
session_id('same_session_id_for_all');
session_start();
echo $_SESSION['aConstantValueForEveryone'];
This works out of the box in PHP. Using the same session id (instead of an random user-uniqe string) to initialize the session for all visitors leads to a session which is the same for all users.
Is it really necessary to use session to achieve the goal or wouldn't it better to use constants?
There is no pure PHP way of sharing information across different
threads in PHP! Except for an "external"
file/database/servervariable/sessionfile solution.
Since some commentators pointed out, that there is serialize/unserialize functionality for Session data which might break data on the transport, there is a solution: In PHP the serialize and unserialize functionality serialize_handler can be configured as needed. See https://www.php.net/manual/session.configuration.php#ini.session.serialize-handler It might be also interesting to have a look at the magic class methods __sleep() and __wakeup() they define how a object behaves on a serialize or unserialize request. https://www.php.net/manual/language.oop5.magic.php#object.sleep ... Since PHP 5.1 there is also a predefined Serializable interface available: https://www.php.net/manual/class.serializable.php
You can declare a Variable in your .htaccess. For Example SetEnv APPLICATION_ENVIRONMENT production and access it in your application with the function getenv('APPLICATION_ENVIRONMENT')
Another solution is to wrap your variable in a "persistent data" class that will automatically restore its data content every time the php script is run.
Your class needs to to the following:
store content of variable into file in __destructor
load content of variable from file in __constructor
I prefer storing the file in JSON format so the content can be easily examined for debugging, but that is optional.
Be aware that some webservers will change the current working directory in the destructor, so you need to work with an absolute path.
I think you can use $_SESSION['aConstantValueForEveryone'] that you can read it on every page on same domain.
Consider to refer to it's manual.

Own SuperGlobal Variable in PHP?

I was reading something about SuplerGlobals like $_SERVER or (see more detail PHP Manual Superglobals) the other day, now, I'm asking me:
Is it possible to implement own SuperGlobals?
Beside of Constants...
So for example user A writes something in the Variable which, if User B is calling it can see.
Something like a server wide Session Variable or something.
Please don't be to hard, if its a silly question :)
I know there are couple of ways outside, like SQL, Xml and Stuff, but maybe...
Your whole idea of PHP superglobals it wrong.
These variables are always available in terms of just one script runtime, no the whole site.
PHP doesn't have context which can be shared between users. You should some replacement like SQL server or file. You may also check some extensions like memcache which might help you achieve your goal.
I was reading something about SuplerGlobals like $_SERVER or (see more detail PHP Manual Superglobals) the other day, now, I'm asking me:
Is it possible to implement own SuperGlobals? Beside of Constants...
Yes it is possible if you've got the PHP runkit extension.
So for example user A writes something in the Variable which, if User B is calling it can see
That's not what superglobals do - they are variables which exist in global scope (i.e. for the duration of an instance of a script).
If you want to share data between different invocations then you need to send it to your storage tier or (in the case of data for a single client) out to the browser.
Since what you are describing here is effectively a shared session, then the sensible place to implement this would be in the session handler.
This is not possible, you can only see your own session data.
To achieve this you would need to store the data somewhere else. in text files or in a MySQL database would be the most common.
i suppose you can use (asterix)export yourvar="something"(asterix) and to receive it using getenv
sry, dont know how to embed asterix=`, but it is better to avoid it...
If you use apache following could be used:
http://php.net/manual/en/function.apache-setenv.php
same idea, enveroinment variable

Convert big php project from register_globals to _GET["param"]

I have a rather big php site, which was written for php4 and register_globals enabled. It is old custom CMS. Now I want to run it on the php5 hosting without register_globals. Is it possible to change parameters parsing from $id to $_GET["id"] automatically, with some script?
I can get parameters names from wget -r on this site.
It have dozens of php scripts, and it is not very easy to do this change manually.
PS: UPDATE: I want to convert only GET variables. The additional line is $var_name = $_GET["var_name"] for each parameter. This line should be inserted very high in the script, e.g. by adding a new <? ?> section at very top.
Running such tool would introduce great risk of introducing errors in code.
I'd suggest running extract() on superglobals, so that you force register_globals and aplication will work properly.
http://php.net/manual/pl/function.extract.php
Next, when everything will be ok, write an OO wrapper for input parameters, pack it into nice DI Container and start manually transitioning whole script to the new style.
I don't know of any tools that help you in the conversion, but you have several options:
Simulate register globals by doing the same thing that register_globals did: At the beginning of the script, put all variables from GET and POST into the global variable namespace (i.e. via extract). While this is fastest and the most easy solution, it will lead to the security problems that register_globals was known for, and it doesn't help with the performance of your application
Determine the variables that are used and load them only via the init script into $GLOBALS only. Still not nice
Determine the variables that are used and replace the GLOBALS usage with REQUEST
Walk through it manually. This way, you can be sure everything is correct and will have the least trouble afterwards.
From your description, solution 1 or 2 might be the best for you since the cms doesn't seem to be updated anyway (which is a shame).
Although the actual finding/replacing might take more time, doing this manually will most likely result in less bugs / weird behaviour.
If are not the original author of the application, then this manual finding/replacing is also an opportunity for you to become much more familiar with the codebase than some automatic method.
Automatic: fast, almost definitely will result in some horrible bugs
Manual: slower (likely), almost definitely will result in better understanding, less bugs - and any bugs that are introduced will be easier to fix because of your better understanding.

How do I execute PHP that is stored in a MySQL database?

I'm trying to write a page that calls PHP that's stored in a MySQL database. The page that is stored in the MySQL database contains PHP (and HTML) code which I want to run on page load.
How could I go about doing this?
You can use the eval command for this. I would recommend against this though, because there's a lot of pitfalls using this approach. Debugging is hard(er), it implies some security risks (bad content in the DB gets executed, uh oh).
See When is eval evil in php? for instance. Google for Eval is Evil, and you'll find a lot of examples why you should find another solution.
Addition: Another good article with some references to exploits is this blogpost. Refers to past vBulletin and phpMyAdmin exploits which were caused by improper Eval usage.
Easy:
$x // your variable with the data from the DB
<?php echo eval("?>".$x."<?") ?>
Let me know, works great for me in MANY applications, can't help but notice that everyone is quick to say how bad it is, but slow to actually help out with a straight answer...
eval() function was covered in other responses here. I agree you should limit use of eval unless it is absolutely needed. Instead of having PHP code in db you could have just a class name that has method called, say, execute(). Whenever you need to run your custom PHP code just instantiate the class of name you just fetched from db and run ->execute() on it. It is much cleaner solution and gives you great field of flexibility and improves site security significantly.
You can look at the eval function in PHP. It allows you to run arbitrary PHP code. It can be a huge security risk, though, and is best avoided.
Have you considered using your Source Control system to store different forks for the various installations (and the modules that differ among them)? That would be one of several best practices for application configuration I can think of. Yours is not an unusual requirement, so it's a problem that's been solved by others in the past; and storing code in a database is one I think you'd have a hard time finding reference to, or being advised as a best practice.
Good thing you posted the clarification. You've probably unintentionally posed an answer in search of a suitable question.
Read php code from database and save to file with unique name and then include file
this easy way for run php code and debug it.
$uniqid="tmp/".date("d-m-Y h-i-s").'_'.$Title."_".uniqid().".php";
$file = fopen($uniqid,"w");
fwrite($file,"<?php \r\n ".$R['Body']);
fclose($file);
// eval($R['Body']);
include $uniqid;
How I did this is to have a field in the database that identified something unique about the block of code needing to be executed. That one word is in the file name of that code. I put the strings together to point to the php file to be included. example:
$lookFor = $row['page'];
include("resources/" . $lookFor . "Codebase.php");
In this way even if a hacker could access you DB he couldn't put malicious code straight in there to be executed. He could perhaps change the reference word, but unless he could actually put a file directly onto the server it would do him no good. If he could put files directly onto the server, you're sunk then anyway if he really wants to be nasty. Just my two cents worth.
And yes, there are reasons you would want to execute stored code, but there are cons.

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