Interesting header-problem

[Anon]

Hello all,

I stumbled over a class of problems that appeares rather difficult to me. Here's the situation:

I'm developing a vectorbased 3d drawing libary using PHP and GD. The vectors are stored in sessions along with information about image size, colors and so on.

Now I have two flavors of the same problem:
To draw the picture I have to call a function that takes the session data, does with it whatever needs to be done and then generates a png-file inside DOCUMENT_ROOT. Thus I need a webserver-writable directory which certainly is not what I want.
I know that PHP can send images directly by setting the header to content-type: image/png or similar. But if I do this I can no longer access the sessiondata because that needs header information as well.
See the problem? I either get the data to draw the picture but can not send the pic to the user or I send an empty pic...

The second flavor appears when I want to send a datadump via session_encode() to the user (textfile similar to the popular sql-dump in phpMyAdmin).
I either send an empty textfile because I can not access the sessions' content or i can not send at all but have all info.

Long explanation, short problem: Can I access the sessions' content, keep it and then still be able to send a new header such as image/png or text/plain to send a picture or a textfile?

Thanks in advance,

Dominique

[sepodati]

Couldn't you do something like this?

<?
session_start();
//get relevant session data...$name,$address,etc

?>
Regular html page...
<? echo "<img src=\"make_png.php?name=$name&address=$address\">"; ?>
More html

where make_png.php creates it's own headers for a png image and echos the data for the image, but nothing else.

Obviously your sessions will have different data, but hopefully that gives you an idea.

---John Holmes...

[Anon]

Hi,

I thought of that idea, too. Unfortunatelly I'd usually end up with a 30kbyte querystring... that's why I moved on to sessions...

...but thanks anyways

Dominique

[[deleted]]

Well if you really can't use a session in that function, why don't you just pass the session id through the URL, and open the session file manually, session_decode() it and hey presto, session vars without using sessions.

http://www.php.net/manual/en/function.session-decode.php

[sepodati]

Exactly what I was going to say.

<img src="make_png.php?SESSID=<? echo $SESSID; ?>">

Something like that...decode in make_png.php and create your picture headers and data...

---John Holmes...

[Anon]

Whoo... nice idea.
Sessions are stored in mySQL though, I'd have to misuse the session user but hey why not...

I'll definatelly keep that in mind, thx.

Dominique