I really didn't follow all that. But this stuff is not that complex.
header() sets a header to be sent when output goes out. header() does
not send an actual header at that point. If you don't send any output,
then the headers won't go out until the script terminates. If you have
any sort of output buffering enabled, then even if you think you are
sending something, you may only be buffering it, and in that case again
the headers won't go out until the request is done.
Also, ignore_user_abort() controls whether or not your script will be
terminated when we are able to detect that the user has aborted. A user
abort is defined as nobody being around to read the data we are sending
out. If you don't send anything, we can't detect if the browser has
gone away. Generally browsers will redirect as soon as they see a
Location: redirect header, but that could be client-speficic. If the
client sticks around after seeing the redirect and doesn't redirect
until after the server has closed the connection, then there is no way
to force a close. If it does redirect and close its end of the
connection, then if you set ignore_user_abort(false) your script will be
terminated as soon as it tries to send something further and your
shutdown function will be called at that point.
-Rasmus
Liang ZHONG wrote:
> Hi Rasmus,
>
> This may be a little bit long, sorry for taking your time.
>
> It still does not work as expected. I tried some experiment, and found
> that if I called some function or write some code line other then
> calling header(), the register_shutdown_function and other part of codes
> work as expected . For example:
> <?php
> set_time_limit(5);
> function f(){
> set_time_limit(10);
> //doing something time consuming
> }
>
> some_function();
>
> ?>
> The time limit of 5 will be the limit of the some_function() and the 10
> will be the limit of function f() respectively.
>
> Code example:
>
> -----------------------------------------------------------------------------------------------------------------------
>
> <?php
> set_time_limit(1);
> ignore_user_abort(true);
>
> function say_goodbye() {
> $st = connection_status();
> print "Status 1: ".$st."\n";
> set_time_limit(10);
> $st = connection_status();
> print "Status 2: ".$st."\n";
>
> $count=20000000;
> for($i=0; $i<$count; $i++){ }
> print "End!\n";
> exec("touch /home/.nappy/liang/liang.ns2user.info/php/bbb");
> }
>
> register_shutdown_function("say_goodbye");
> print "Sleeping...\n";
>
> $count=10000000;
> for($i=0; $i<$count; $i++){ }
>
> print "Done!\n";
>
> ?>
> ------------------------------------------------------------------------------------------------------------------------
>
> -bash-2.05b$ curl -N liang.ns2user.info/php/v.php
> Sleeping...
> <br />
> <b>Fatal error</b>: Maximum execution time of 1 second exceeded in
> <b>/home/.nappy/liang/liang.ns2user.info/php/v.php</b> on line
> <b>30</b><br />
> Status 1: 2
> Status 2: 2
> End!
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> if I change the time limit from 10 to 5 in function f()
>
> -bash-2.05b$ curl -N liang.ns2user.info/php/v.php
> Sleeping...
> <br />
> <b>Fatal error</b>: Maximum execution time of 1 second exceeded in
> <b>/home/.nappy/liang/liang.ns2user.info/php/v.php</b> on line
> <b>30</b><br />
> Status 1: 2
> Status 2: 2
> <br />
> <b>Fatal error</b>: Maximum execution time of 5 seconds exceeded in
> <b>/home/.nappy/liang/liang.ns2user.info/php/v.php</b> on line
> <b>14</b><br />
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Change both the time limit to 10 will result:
>
> -bash-2.05b$ curl -N liang.ns2user.info/php/v.php
> Sleeping...
> Done!
>
> Status 1: 0
> Status 2: 0
> End!
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> But if the some_function is header() then the rule above does not work.
> It seems the function f()'s time limit also rule the header(). Only
> after the registered shutdown function finishes runing normally or by
> hit the expire time limit, will the header() return page to browser/http
> user agent. Example code with suggestion from Rasmus as:
>
> ------------------------------------------------------------------------------------------------------------------
>
> <?php
>
> set_time_limit(5);
>
> function f(){
> set_time_limit(100);
> $count=500000000;
> for($i=0; $i<$count; $i++){
> //sit here and loop for a bit so we can have time to hit Stop...
> echo "a \n"; flush();
> }
> echo "end";
> exec("touch /tmp/aaa");
> }
>
> register_shutdown_function('f');
>
> ignore_user_abort(true);
> header("Content-type: text/plain");
> header("Location: y.html");
>
> echo "foo\n"; flush();
> for($i=0;$i<10;$i++) { echo $i; sleep(1); }
> $fp = fopen("/tmp/foo.txt","a");
> fputs($fp,$i);
> fclose($fp);
> ?>
>
> ------------------------------------------------------------------------------------------------------------------
>
> After the file /tmp/foo.txt has been created, before the file /tmp/aaa
> being created, the y.html will not get to the browser or perl program
> using LWP::UserAgent. I think it is no way to close the connection
> actively by the php program to deliver the page sooner to end the http
> request, even I add lines and make code like this does not work:
>
> ----------------------------------------------------------------
> header("Content-type: text/plain");
> header("Cache-Control: no-store, no-cache");
> header("Location: y.html");
> header("Connection: close");
> ----------------------------------------------------------------
>
> My project act as a broker for user agent to a library database server
> called z39.50. Upon the request from user agent, my program need to
> connect a z39.50 server, getting data back 1 by 1, transforming to
> sepcial xml format and sending back to the request party. When the data
> repository is huge (sometimes up to million records), I have to get
> partial data transform and send back to user agent (normally a piece of
> perl code, called harvester) with a resumption token. The harvester will
> in a while loop send out another http request with the last resumption
> token and fetch data of next part, until finish all data fetching. The
> time to connect the database and do the query is a constant overhead. So
> it is not a good design that program need to connect the database and
> query upon each request with or with out resumption token. So my design
> is to connect to database and query only when the first initial request
> comes, and reponse back with partical data using header() and continue
> getting back data from z39 server. Upon next request, the program will
> only need to make sure the data needed has already stored in the
> harddrive and transform them and send them back.
> Since the user harvester agent normally has a 180 second timeout, it is
> necessary to respond within that period of time.
>
> I really need your suggestion. Thank you very much again.
>
>
> Liang
>
>
>
>
>> Try somthing lik
>
>
> e this:
>
>>
>> <?php
>> ignore_user_abort(true);
>> header("Location: redirect2.html");
>> echo "foo\n"; flush();
>> for($i=0;$i<10;$i++) { echo $i; sleep(1); }
>> $fp = fopen("/tmp/foo.txt","a");
>> fputs($fp,$i);
>> fclose($fp);
>> ?>
>>
>>
>> Liang ZHONG wrote:
>> > Sorry, does not seem to work here. The code below takes minutes to show
>> > up in browser.
>> >
>> > Any more suggestion?
>> >
>> ---------------------------------------------------------------------------------------
>>
>> >
>> > <?php
>> >
>> > set_time_limit(5);
>> >
>> > function f(){
>> > set_time_limit(100);
>> > $count=500000000;
>> > for($i=0; $i<$count; $i++){ }
>> > echo "end";
>> > exec("touch /home/.nappy/liang/liang.ns2user.info/php/aaa");
>> > }
>> >
>> > register_shutdown_function('f');
>> >
>> > ignore_user_abort(true);
>> > header("Content-type: text/plain");
>> > header("Location: y.html");
>> >
>> > $count=50000;
>> > for($i=0; $i<$count; $i++){ echo " \n"; }
>> > flush();
>> > ?>
>> >
>> ---------------------------------------------------------------------------------------
>>
>> >
>> >
>> > Liang
>> >
>> >>
>> >> If you don't flush some output after setting the header() then the
>> >> headers won't go out until the end of the request. So do something
>> like:
>> >>
>> >> ignore_user_abort(true);
>> >> header("Location: http://whatever";);
>> >> echo "foo\n"; flush();
>> >>
>> >> Then whatever comes after this should run and the browser is long
>> gone.
>> >>
>> >> -Rasmus
>> >>
>> >>
>> >> Liang ZHONG wrote:
>> >> > I think I did not express myself clearly.
>> >> >
>> >> > What I want is to be able to redirect user an existing page (let
>> them
>> >> > get it immediately), and to close the connection actively, NOT
>> >> passively
>> >> > by user abort, at last, to run the function in background.
>> >> >
>> >> > But the redirecting using function header() with location has a
>> problem
>> >> > that header() always does return the page to user after the entire
>> >> > program, including registered showdown function finish running,
>> >> which is
>> >> > against the will. I put a time consuming task into a function that
>> >> > registered to be a shutdown function and hoping it runs after the
>> user
>> >> > has got the redirected page and the connection has been closed. But
>> >> > experiements (using browsers, curl command line tool as well as
>> >> > perl::LWP code) show that the user got the redirected page only
>> after
>> >> > the shutdown function finished, which is against the description of
>> >> > register_shutdown_function at php website.
>> >> >
>> >> > It seems only header() function use to redirect page has this
>> problem
>> >> > (not executed until register_shutdown_function finished) while other
>> >> > functions like print()/echo(), exec() have not.
>> >> >
>> >> > The code looks like:
>> >> >
>> >>
>> ---------------------------------------------------------------------------------------------
>>
>> >>
>> >> >
>> >> > <?php
>> >> > set_time_limit(1);
>> >> >
>> >> > function f(){
>> >> > set_time_limit(20);
>> >> > $count=50000000;
>> >> > for($i=0; $i<$count; $i++){ }
>> >> > echo "end";
>> >> > exec("touch /home/.nappy/liang/liang.ns2user.info/php/aaa");
>> >> > }
>> >> >
>> >> > register_shutdown_function('f');
>> >> >
>> >> > header("Content-type: text/plain");
>> >> > header("Location: y.html");
>> >> > ?>
>> >> >
>> >>
>> ---------------------------------------------------------------------------------------------
>>
>> >>
>> >> >
>> >> >
>> >> > http client who sends the request to the php program will only
>> get the
>> >> > page back as response after function f finsihes (file aaa created).
>> >> > Changing the $count will make a lot difference.
>> >> >
>> >> > My BIGGEST question is:
>> >> > How to make user get the redirect page immediately after the
>> >> header() is
>> >> > called, and not until function f() ends, while making sure that the
>> >> > function f() will finally fully (and might slowly) execute?
>> >> >
>> >> > Thank you very much for kindly replying.
>> >> >
>> >> > With high respect,
>> >> >
>> >> > Liang
>> >> >
>> >> >
>> >> >>
>> >> >> Liang ZHONG wrote:
>> >> >> > My Question is:
>> >> >> > What is the correct way to keep the function running after I
>> >> >> redirect an
>> >> >> > existing page to http client (which I want the client get
>> >> immediately)
>> >> >> > and then immediately close the connection?
>> >> >>
>> >> >> ignore_user_abort(true);
>> >> >>
>> >> >> -Rasmus
>> >> >>
>> >> >> --
>> >> >> PHP General Mailing List (http://www.php.net/)
>> >> >> To unsubscribe, visit: http://www.php.net/unsub.php
>> >> >>
>> >> >
>> >>
>> >> --
>> >> PHP General Mailing List (http://www.php.net/)
>> >> To unsubscribe, visit: http://www.php.net/unsub.php
>> >>
>> >
>>
>
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