Header Processing

[Call Me Tom]

I was looking at an application with the following code snippet:

ob_start();
session_name('f oo');
session_start() ;
if (!$_SESSION['bar']) {
header("Locatio n: http://" . $_SERVER['HTTP_HOST'] .
dirname($_SERVE R['PHP_SELF']) . "/index.php");
ob_end_clean();
exit();
}

I am under the impression that the "header" redirection is immediate.
Am I correct or will the 'ob_end_clean() ' and 'exit()' actually
process.

Tom

[Erwin Moller]

Re: Header Processing


Call Me Tom schreef:

Hi Tom,

I was looking at an application with the following code snippet:
>
ob_start();
session_name('f oo');
session_start() ;
if (!$_SESSION['bar']) {
header("Locatio n: http://" . $_SERVER['HTTP_HOST'] .
dirname($_SERVE R['PHP_SELF']) . "/index.php");
ob_end_clean();
exit();
}
>
I am under the impression that the "header" redirection is immediate.

That is wrong.
This is not like, for example ASP/VB's Response.Redire ct.
header() function in PHP does excact what it says and nothing more:
Setting a header.

Am I correct or will the 'ob_end_clean() ' and 'exit()' actually
process.

They will be processed.

>
Tom

Bottomline: If you need a 'redirect' via header("Locatio n...") always
call exit after that, or the script will merely run on untill it ends.

Regards,
Erwin Moller

--
=============== =============
Erwin Moller
Now dropping all postings from googlegroups.
Why? http://improve-usenet.org/
=============== =============

[Jerry Stuckle]

Re: Header Processing

Erwin Moller wrote:

>
Call Me Tom schreef:
>
Hi Tom,
>

>I was looking at an application with the following code snippet:
>>
>ob_start();
>session_name(' foo');
>session_start( );
>if (!$_SESSION['bar']) { header("Locatio n: http://" .
>$_SERVER['HTTP_HOST'] . dirname($_SERVE R['PHP_SELF']) .
>"/index.php");
> ob_end_clean();
> exit();
>}
>>
>I am under the impression that the "header" redirection is immediate.

>
That is wrong.
This is not like, for example ASP/VB's Response.Redire ct.
header() function in PHP does excact what it says and nothing more:
Setting a header.
>

>Am I correct or will the 'ob_end_clean() ' and 'exit()' actually
>process.

>
They will be processed.
>

>>
>Tom

>
Bottomline: If you need a 'redirect' via header("Locatio n...") always
call exit after that, or the script will merely run on untill it ends.
>
Regards,
Erwin Moller
>

Almost correct, Erwin,

The script will continue until the redirect actually takes place. That
will be after the header is sent to the client and the client responds.

So while the rest of this script will run, another script with a
relatively long run time probably will be interrupted.

--
=============== ===
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attgl obal.net
=============== ===

[Erwin Moller]

Re: Header Processing


Jerry Stuckle schreef:

Erwin Moller wrote:

>>
>Call Me Tom schreef:
>>
>Hi Tom,
>>

>>I was looking at an application with the following code snippet:
>>>
>>ob_start();
>>session_name( 'foo');
>>session_start ();
>>if (!$_SESSION['bar']) { header("Locatio n: http://" .
>>$_SERVER['HTTP_HOST'] . dirname($_SERVE R['PHP_SELF']) .
>>"/index.php");
>> ob_end_clean();
>> exit();
>>}
>>>
>>I am under the impression that the "header" redirection is immediate.

>>
>That is wrong.
>This is not like, for example ASP/VB's Response.Redire ct.
>header() function in PHP does excact what it says and nothing more:
>Setting a header.
>>

>>Am I correct or will the 'ob_end_clean() ' and 'exit()' actually
>>process.

>>
>They will be processed.
>>

>>>
>>Tom

>>
>Bottomline: If you need a 'redirect' via header("Locatio n...") always
>call exit after that, or the script will merely run on untill it ends.
>>
>Regards,
>Erwin Moller
>>

>
Almost correct, Erwin,
>
The script will continue until the redirect actually takes place. That
will be after the header is sent to the client and the client responds.
>
So while the rest of this script will run, another script with a
relatively long run time probably will be interrupted.
>

Hi Jerry,

Good point, Jerry.
If a programmer WANTS to keep executing the script after the
locationheader (some longrunning DB actions eg), this might cause some
hard-to-find bugs.
Since the time the remainder of the scripts has depends on the speed to
the client.

Since I never leave my script running after a Location header, I never
gave that route of problems much thought. ;-)

Hypothetical question: Suppose I deliberately want to keep the script
running after the header("Locatio n.."), will using
ignore_user_abo rt(TRUE) avoid this problem?

Regards,
Erwin Moller


--
=============== =============
Erwin Moller
Now dropping all postings from googlegroups.
Why? http://improve-usenet.org/
=============== =============

[Jerry Stuckle]

Re: Header Processing

Erwin Moller wrote:

>
Jerry Stuckle schreef:

>Erwin Moller wrote:

>>>
>>Call Me Tom schreef:
>>>
>>Hi Tom,
>>>
>>>I was looking at an application with the following code snippet:
>>>>
>>>ob_start() ;
>>>session_name ('foo');
>>>session_star t();
>>>if (!$_SESSION['bar']) { header("Locatio n: http://" .
>>>$_SERVER['HTTP_HOST'] . dirname($_SERVE R['PHP_SELF']) .
>>>"/index.php");
>>> ob_end_clean();
>>> exit();
>>>}
>>>>
>>>I am under the impression that the "header" redirection is immediate.
>>>
>>That is wrong.
>>This is not like, for example ASP/VB's Response.Redire ct.
>>header() function in PHP does excact what it says and nothing more:
>>Setting a header.
>>>
>>>Am I correct or will the 'ob_end_clean() ' and 'exit()' actually
>>>process.
>>>
>>They will be processed.
>>>
>>>>
>>>Tom
>>>
>>Bottomline: If you need a 'redirect' via header("Locatio n...") always
>>call exit after that, or the script will merely run on untill it ends.
>>>
>>Regards,
>>Erwin Moller
>>>

>>
>Almost correct, Erwin,
>>
>The script will continue until the redirect actually takes place.
>That will be after the header is sent to the client and the client
>responds.
>>
>So while the rest of this script will run, another script with a
>relatively long run time probably will be interrupted.
>>

>
Hi Jerry,
>
Good point, Jerry.
If a programmer WANTS to keep executing the script after the
locationheader (some longrunning DB actions eg), this might cause some
hard-to-find bugs.
Since the time the remainder of the scripts has depends on the speed to
the client.
>
Since I never leave my script running after a Location header, I never
gave that route of problems much thought. ;-)
>
Hypothetical question: Suppose I deliberately want to keep the script
running after the header("Locatio n.."), will using
ignore_user_abo rt(TRUE) avoid this problem?
>
Regards,
Erwin Moller
>
>

Yep, it should, but I would say no guarantee - the web server may
terminate the thread (although I don't know of any cases where it will
for sure). But it would be better to just delay the header() call, if
possible, or start another script as a background task. Then you're
more sure it will not be killed.

--
=============== ===
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attgl obal.net
=============== ===