Programming Forums > Web Development and Design > PHP

Sane · Jul 24th, 2006, 10:42 PM

I tried searching this on google, but all I got was unrelated trash like how to upgrade your computer's RAM and such.

Is there a way to store a variable within one session of a page, and recall it at a later time? Keeping data inside the RAM? Without storing the value in a data file?

I don't think this is possible, or else I think I would have stumbled across it already. But it would be so perfect if it were. I will slap PHP across the face if it can't.

Darkhack · Jul 24th, 2006, 10:56 PM

There are SESSION and COOKIE variables if that is what you mean. I don't seem to exactly understand what your question is. Here are some links that might help.

http://www.w3schools.com/php/php_cookies.asp
http://www.w3schools.com/php/php_sessions.asp

Sane · Jul 24th, 2006, 10:58 PM

No, I mean like load an array of 100 random integers in to the RAM in page: "init.php", and then display them straight from the RAM on: "index.php". So then anyone seeing "index.php" would see the exact same thing... as long as "init.php" has been accessed at least once. Then every time "init.php" is accessed, it would cause a different result to show in "index.php".

Note: This is not actually what I'm doing. Just a demonstration of what it could be used for.

DaWei · Jul 24th, 2006, 11:19 PM

Not on your ordinary, modern, multiple-processed, controlled-by-an-OS-that-ain't you, memory-managed system, no.

titaniumdecoy · Jul 24th, 2006, 11:52 PM

Your best bet would probably be to write data to a temporary file, and load that in the subsequent page.

Sane · Jul 25th, 2006, 8:58 AM

Oh wow... so I think this really means that Python can sometimes be faster than PHP. Both in efficiency and production. If we were to do this in Python, it would be...

(Toggle Plain Text)

        ...

        @cherrypy.expose
        def init(self):
            self.random_ints = [str(random.randrange(10)) for i in range(100)]
        
        @cherrypy.expose
        def index(self):
            return '<br />'.join(self.random_ints)

        ...

And due to PHP not being able to do the same... there will be a dramatic loss in potential speed. The relevant data is going to be needlessly... loaded, parsed, modified, outputted, formatted, then saved... every time a page is accessed. That makes me sad.

*slaps PHP*

Darkhack · Jul 25th, 2006, 9:19 AM

I'm not a python guy but I doubt even Python stores it in RAM. If I understand this correctly you want to be able to load/generate data by visiting init.php but then have the same data be displayed to everyone on index.php.

You have to store it somewhere on the disk of the server. Either a database, flat-file, or something of the sort. Another possibility is to generate the entire html on the spot. When you visit init.php it will then generate a static html file called index.html that gets updated through init.php. The server will cache some popular pages in RAM although there is no way to force something to stay in RAM.

Sane · Jul 25th, 2006, 11:53 AM

No, Python definitely stores it in the RAM. The way Python works, is it is its own server. The HTTP server is embedded within your Python script. So the entire site, everything that can be seen and downloaded, is contained within (at least) one file. You're basically extending the server's capabilities to decide what pages are linked to what.

You don't need Apache to run it (although you can), all you need is one Python script and the necessary files that are used to embed the server (CherryPy). It most certainly is held inside the RAM, or else around 6000 pages on my website would not be working right now.

Since PHP can not do this, it's limiting a lot of potential speed ups in efficiency. PHP could get nowhere near the speed of Python+CherryPy in some situations.

DaWei · Jul 25th, 2006, 12:07 PM

Sounds like you're talking about an ability of CherryPy, not Python, per se. This is a question of a parent process treating all services as children and arranging for shared memory, I would guess.

Sane · Jul 25th, 2006, 12:20 PM

Well, yes. I chose to ignore that fact. I would have hoped PHP had some way to communicate back to Apache to manage memory (PHP --> Apache --> PHP).

Not necessarily in the same manner Python does it (CherryPy --> Python --> CherryPy).

Jul 24th, 2006, 10:42 PM	#1
Sane Programming Guru Join Date: Apr 2005 Posts: 1,827 Rep Power: 5	Retaining Variables In Memory? I tried searching this on google, but all I got was unrelated trash like how to upgrade your computer's RAM and such. Is there a way to store a variable within one session of a page, and recall it at a later time? Keeping data inside the RAM? Without storing the value in a data file? I don't think this is possible, or else I think I would have stumbled across it already. But it would be so perfect if it were. I will slap PHP across the face if it can't.

Jul 24th, 2006, 11:19 PM	#4
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	Not on your ordinary, modern, multiple-processed, controlled-by-an-OS-that-ain't you, memory-managed system, no. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Jul 25th, 2006, 8:58 AM	#6
Sane Programming Guru Join Date: Apr 2005 Posts: 1,827 Rep Power: 5	Oh wow... so I think this really means that Python can sometimes be faster than PHP. Both in efficiency and production. If we were to do this in Python, it would be... (Toggle Plain Text) ... @cherrypy.expose def init(self): self.random_ints = [str(random.randrange(10)) for i in range(100)] @cherrypy.expose def index(self): return '<br />'.join(self.random_ints) ... ... @cherrypy.expose def init(self): self.random_ints = [str(random.randrange(10)) for i in range(100)] @cherrypy.expose def index(self): return '<br />'.join(self.random_ints) ... And due to PHP not being able to do the same... there will be a dramatic loss in potential speed. The relevant data is going to be needlessly... loaded, parsed, modified, outputted, formatted, then saved... every time a page is accessed. That makes me sad. slaps PHP

Jul 25th, 2006, 12:07 PM	#9
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	Sounds like you're talking about an ability of CherryPy, not Python, per se. This is a question of a parent process treating all services as children and arranging for shared memory, I would guess. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

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Jul 24th, 2006, 10:56 PM	#2
Darkhack Hobbyist Programmer Join Date: Dec 2005 Location: Kansas City Posts: 102 Rep Power: 3	There are SESSION and COOKIE variables if that is what you mean. I don't seem to exactly understand what your question is. Here are some links that might help. http://www.w3schools.com/php/php_cookies.asp http://www.w3schools.com/php/php_sessions.asp

Jul 24th, 2006, 10:58 PM	#3
Sane Programming Guru Join Date: Apr 2005 Posts: 1,827 Rep Power: 5	No, I mean like load an array of 100 random integers in to the RAM in page: "init.php", and then display them straight from the RAM on: "index.php". So then anyone seeing "index.php" would see the exact same thing... as long as "init.php" has been accessed at least once. Then every time "init.php" is accessed, it would cause a different result to show in "index.php". Note: This is not actually what I'm doing. Just a demonstration of what it could be used for.

Jul 24th, 2006, 11:52 PM	#5
titaniumdecoy Expert Programmer Join Date: Nov 2005 Posts: 841 Rep Power: 3	Your best bet would probably be to write data to a temporary file, and load that in the subsequent page.

Jul 25th, 2006, 9:19 AM	#7
Darkhack Hobbyist Programmer Join Date: Dec 2005 Location: Kansas City Posts: 102 Rep Power: 3	I'm not a python guy but I doubt even Python stores it in RAM. If I understand this correctly you want to be able to load/generate data by visiting init.php but then have the same data be displayed to everyone on index.php. You have to store it somewhere on the disk of the server. Either a database, flat-file, or something of the sort. Another possibility is to generate the entire html on the spot. When you visit init.php it will then generate a static html file called index.html that gets updated through init.php. The server will cache some popular pages in RAM although there is no way to force something to stay in RAM.

Jul 25th, 2006, 11:53 AM	#8
Sane Programming Guru Join Date: Apr 2005 Posts: 1,827 Rep Power: 5	No, Python definitely stores it in the RAM. The way Python works, is it is its own server. The HTTP server is embedded within your Python script. So the entire site, everything that can be seen and downloaded, is contained within (at least) one file. You're basically extending the server's capabilities to decide what pages are linked to what. You don't need Apache to run it (although you can), all you need is one Python script and the necessary files that are used to embed the server (CherryPy). It most certainly is held inside the RAM, or else around 6000 pages on my website would not be working right now. Since PHP can not do this, it's limiting a lot of potential speed ups in efficiency. PHP could get nowhere near the speed of Python+CherryPy in some situations.

Jul 25th, 2006, 12:20 PM	#10
Sane Programming Guru Join Date: Apr 2005 Posts: 1,827 Rep Power: 5	Well, yes. I chose to ignore that fact. I would have hoped PHP had some way to communicate back to Apache to manage memory (PHP --> Apache --> PHP). Not necessarily in the same manner Python does it (CherryPy --> Python --> CherryPy).

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Programming Forums > Web Development and Design > PHP

Retaining Variables In Memory?