PHP Session Start?

_sh

Being an ASP coder I'm used to Session fuctionality just being there whenever I need to create or read one - I don't quite understand this session_start(); command, could someone give me a brief overview as to when/where its required, if at all?

Many thanks!

_sh

I have to comment that I'm disappointed - having had 17 views so far (clearly by users interested in the subject) no one has taken the time to respond to this basic request for information?

I have been searching for a long time this evening trying to resolve this query before I proceed with developing my application, please could someone take a few minutes to reply in order to assist me!?!?

bradgrafelman

ashleyhall wrote:
I have to comment that I'm disappointed - having had 17 views so far

Sorry our volunteer system has disappointed you, I hope others will dedicate time in the future to answering your questions as soon as they are posted.

ashleyhall wrote:
clearly by users interested in the subject

Clearly? Really?

ashleyhall wrote:
could someone give me a brief overview as to when/where its required

It's required whenever you wish to access (whether that be to retrieve or store) session data. As to the "where", you simply need to call the function before you output anything (else you'll get the infamous "headers already sent" error), and of course before you attempt to access the session data.

In other words, PHP doesn't populate the $_SESSION array until you tell it, namely by calling [man]session_start/man.

_sh

bradgrafelman;10878717 wrote:
Sorry our volunteer system has disappointed you, I hope others will dedicate time in the future to answering your questions as soon as they are posted.

Sadly your unnecessary sarcastic response has overshadowed the constructive element of your reply. I was merely expressing my disappointment at a number of users of this forum viewing my topic yet no bothering to reply, when the likelihood is that those viewing it knew of the answer.

I run a large forum myself and also participate in many, if I know the answer to something, I'll post it immediately.

Eitherway, thanks for your help - I presume this method is more efficient than the ASP method whereby Sessions are continually populated and sent to/from the browser within each transaction.

bradgrafelman

ashleyhall wrote:
Sadly your unnecessary sarcastic response has overshadowed the constructive element of your reply.

shrug When new (and old, I suppose) users come here and impatiently bump their 2-hour-old posts, it just rubs me the wrong way.

ashleyhall wrote:
I presume this method is more efficient than the ASP method whereby Sessions are continually populated and sent to/from the browser within each transaction.

I'm no expert on the matter, but I would have to agree. It makes sense, I suppose; why bother doing all of the session handling (checking for previous id, checking for file on server, opening file, populating array... then reversing the process to save data when the script is done executing) when it turns out that you don't even need session data. Note, however, that PHP can imitate this ASP-ness in terms of session behavior if you enable the session.auto_start PHP directive.

_sh

Note, however, that PHP can imitate this ASP-ness in terms of session behavior if you enable the session.auto_start PHP directive

Ahhh I like the sound of this, has it been proven to cause any additional processing power/load? I presume it would be an insignificant load for a low traffic website? Whats your/others view on this?

bradgrafelman

Well like I said, it will incur additional overhead than normal simply because it has to do all of the session handling for every PHP request, not just the scripts that use session_start().

Also note that there might be timing issues between the time PHP finishes writing data and closing the session file and the user's next page request. Sometimes people have manually called [man]session_write_close/man before doing a header() redirect, for example, just to speed up the process.

JPnyc

The moderators of this forum are volunteers. They volunteer to moderate the forum. They have no special responsibility for answering questions, any more than any other forum member does. That's the function of an open forum, you post your question and anyone knowing the answer and wishing to post it, does. We can't guarantee answers will be given, and especially not within a particular time frame.

_sh

JPnyc;10878758 wrote:
The moderators of this forum are volunteers. They volunteer to moderate the forum. They have no special responsibility for answering questions, any more than any other forum member does. That's the function of an open forum, you post your question and anyone knowing the answer and wishing to post it, does. We can't guarantee answers will be given, and especially not within a particular time frame.

I am also the owner/administrator/moderator of a large forum, I fully understand the role of such individuals, I'm not disputing that nor need it clarifying - my complaint wasn't moderator targeted, and eitherway we're now going off topic.