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<HTML
><HEAD
><TITLE
>Connection Handling</TITLE
><META
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><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="FEATURE-CONNECTION-HANDLING"
>Connection Handling</A
></H1
><P
> The following applies to PHP version 3.0.7 and later.
</P
><P
> Internally in PHP a connection status is maintained. There are 3 possible states:
<P
></P
><UL
><LI
><P
>0 - NORMAL
</P
></LI
><LI
><P
>1 - ABORTED
</P
></LI
><LI
><P
>2 - TIMEOUT
</P
></LI
></UL
>
</P
><P
> When a PHP script is running normally the NORMAL state, is active. If the
remote client disconnects the ABORTED state flag is turned on. A remote client
disconnect is usually caused by the user hitting his STOP button. If the PHP-imposed
time limit (see <A
HREF="function.set-time-limit.html"
><B
CLASS="FUNCTION"
>set_time_limit()</B
></A
>) is hit, the TIMEOUT state flag
is turned on.
</P
><P
> You can decide whether or not you want a client disconnect to cause your script to be
aborted. Sometimes it is handy to always have your scripts run to completion even if
there is no remote browser receiving the output. The default behaviour is however for your
script to be aborted when the remote client disconnects. This behaviour can be set via the
ignore_user_abort php3.ini directive as well as through the corresponding php3_ignore_user_abort
Apache .conf directive or with the <A
HREF="function.ignore-user-abort.html"
><B
CLASS="FUNCTION"
>ignore_user_abort()</B
></A
> function. If you do
not tell PHP to ignore a user abort and the user aborts, your script will terminate. The one
exception is if you have registered a shutdown function using
<A
HREF="function.register-shutdown-function.html"
><B
CLASS="FUNCTION"
>register_shutdown_function()</B
></A
>. With a shutdown function, when the remote user hits
his STOP button, the next time your script tries to output something PHP will detect that the connection
has been aborted and the shutdown function is called. This shutdown function will also get called at
the end of your script terminating normally, so to do something different in case of a client
diconnect you can use the <A
HREF="function.connection-aborted.html"
><B
CLASS="FUNCTION"
>connection_aborted()</B
></A
> function. This function will return
true if the connection was aborted.
</P
><P
> Your script can also be terminated by the built-in script timer. The default timeout is 30 seconds.
It can be changed using the max_execution_time php3.ini directive or the corresponding
php3_max_execution_time Apache .conf directive as well as with the <A
HREF="function.set-time-limit.html"
><B
CLASS="FUNCTION"
>set_time_limit()</B
></A
>
function. When the timer expires the script will be aborted and as with the above client disconnect
case, if a shutdown function has been registered it will be called. Within this shutdown function
you can check to see if a timeout caused the shutdown function to be called by calling the
<A
HREF="function.connection-timeout.html"
><B
CLASS="FUNCTION"
>connection_timeout()</B
></A
> function. This function will return true if a timeout caused
the shutdown function to be called.
</P
><P
> One thing to note is that both the ABORTED and the TIMEOUT states can be active at the same time. This
is possible if you tell PHP to ignore user aborts. PHP will still note the fact that a user may have
broken the connection, but the script will keep running. If it then hits the time limit it will be aborted
and your shutdown function, if any, will be called. At this point you will find that
<A
HREF="function.connection-timeout.html"
><B
CLASS="FUNCTION"
>connection_timeout()</B
></A
> and <A
HREF="function.connection-aborted.html"
><B
CLASS="FUNCTION"
>connection_aborted()</B
></A
> return true. You can also
check both states in a single call by using the <A
HREF="function.connection-status.html"
><B
CLASS="FUNCTION"
>connection_status()</B
></A
>. This function
returns a bitfield of the active states. So, if both states are active it would return 3, for example.
</P
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