What if the user closes the browser while INSERT INTO MySQL?

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This maybe a newbie question.

Consider the following concept,

~/index.php

#1. Fetch data from an external webpage using PHP Curl;
#2. Preg_match/Prepare Data to INSERT from local MySQL; - this may take a
few secs
#3. While Loop { INSERT data (from #2) into local MySQL } - this may take
only mili secs.

Suppose this code is run by a random user (say, my website visitor), and
he/she closes the browser while the code was running. The real problem is
when the browser is closed while #3 is executing. Because only portion of
data is inserted, ~/index.php, and it doesn't know if it needs to visit the
site again (i.e. repeat from #1 -> over visiting the same webpage /
possibility of inaccurate data in local MySQL).

Has anyone come across with a similar problem? Do I need to use other
programming languages like C to execute the code from #2 in order not
to depend upon users' browser status?

Another general question : Is there a way to make sure all the data is
INSERTED in a while loop once it's triggered?

many thanks in advance,

- Anton

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Re: What if the user closes the browser while INSERT INTO MySQL? (PHP/MySQL)

On Friday 16 April 2010 11:39, Antonio PHP wrote:
> This maybe a newbie question.
>
> Consider the following concept,
>
> ~/index.php
>
> #1. Fetch data from an external webpage using PHP Curl;
> #2. Preg_match/Prepare Data to INSERT from local MySQL; - this may take a
> few secs
> #3. While Loop { INSERT data (from #2) into local MySQL } - this may take
> only mili secs.
>
> Suppose this code is run by a random user (say, my website visitor), and
> he/she closes the browser while the code was running. The real problem is
> when the browser is closed while #3 is executing. Because only portion of
> data is inserted, ~/index.php, and it doesn't know if it needs to visit t=
he
> site again (i.e. repeat from #1 -> over visiting the same webpage /
> possibility of inaccurate data in local MySQL).

The server does not know if the browser is closed or not (or if the network=
=20
connection is losted). It will continue to execute the code until finnished.

=2D-=20
J=F8rn Dahl-Stamnes
homepage: http://www.dahl-stamnes.net/dahls/

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Re: What if the user closes the browser while INSERT INTO MySQL?(PHP/MySQL)

> > Consider the following concept,
> >
> > ~/index.php
> >
> > #1. Fetch data from an external webpage using PHP Curl;
> > #2. Preg_match/Prepare Data to INSERT from local MySQL; - this may take a
> > few secs
> > #3. While Loop { INSERT data (from #2) into local MySQL } - this may take
> > only mili secs.
> >
> > Suppose this code is run by a random user (say, my website visitor), and
> > he/she closes the browser while the code was running. The real problem is
> > when the browser is closed while #3 is executing.

> The server does not know if the browser is closed or not (or if the network
> connection is losted). It will continue to execute the code until finnished.

I'm not sure that's exactly correct. "The default behaviour is however
for your script to be aborted when the remote client disconnects."
http://www.php.net/manual/en/features.connection-handling.ph p

You can certainly set a script not to terminate if the user aborts
during the page request using ignore_user_abort() or a php.ini setting.

HTH

Nigel

P.S. Sorry to the other list users for a PHP oriented discussion.



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Re: What if the user closes the browser while INSERT INTO MySQL?

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As a side-note: letting a random user (such as your website visitor) wait
for a couple of seconds is usually not good practice, unless you have a ver=
y
good incentive for them to do so.

2010/4/16 J=F8rn Dahl-Stamnes

> On Friday 16 April 2010 11:39, Antonio PHP wrote:
> > This maybe a newbie question.
> >
> > Consider the following concept,
> >
> > ~/index.php
> >
> > #1. Fetch data from an external webpage using PHP Curl;
> > #2. Preg_match/Prepare Data to INSERT from local MySQL; - this may take=
a
> > few secs
> > #3. While Loop { INSERT data (from #2) into local MySQL } - this may ta=
ke
> > only mili secs.
> >
> > Suppose this code is run by a random user (say, my website visitor), an=
d
> > he/she closes the browser while the code was running. The real problem =
is
> > when the browser is closed while #3 is executing. Because only portion =
of
> > data is inserted, ~/index.php, and it doesn't know if it needs to visit
> the
> > site again (i.e. repeat from #1 -> over visiting the same webpage /
> > possibility of inaccurate data in local MySQL).
>
> The server does not know if the browser is closed or not (or if the netwo=
rk
> connection is losted). It will continue to execute the code until
> finnished.
>
> --
> J=F8rn Dahl-Stamnes
> homepage: http://www.dahl-stamnes.net/dahls/
>
> --
> MySQL General Mailing List
> For list archives: http://lists.mysql.com/mysql
> To unsubscribe: http://lists.mysql.com/mysql?unsub=3Dgbrits@gmail.com
>
>

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Re: What if the user closes the browser while INSERT INTOMySQL? (PHP/MySQL)

http://php.net/manual/en/function.ignore-user-abort.php



/ Carsten



On Fri, 16 Apr 2010 18:39:07 +0900, Antonio PHP

wrote:

> This maybe a newbie question.

>

> Consider the following concept,

>

> ~/index.php

>

> #1. Fetch data from an external webpage using PHP Curl;

> #2. Preg_match/Prepare Data to INSERT from local MySQL; - this may take

a

> few secs

> #3. While Loop { INSERT data (from #2) into local MySQL } - this may

take

> only mili secs.

>

> Suppose this code is run by a random user (say, my website visitor), and

> he/she closes the browser while the code was running. The real problem

is

> when the browser is closed while #3 is executing. Because only portion

of

> data is inserted, ~/index.php, and it doesn't know if it needs to visit

the

> site again (i.e. repeat from #1 -> over visiting the same webpage /

> possibility of inaccurate data in local MySQL).

>

> Has anyone come across with a similar problem? Do I need to use other

> programming languages like C to execute the code from #2 in order not

> to depend upon users' browser status?

>

> Another general question : Is there a way to make sure all the data is

> INSERTED in a while loop once it's triggered?

>

> many thanks in advance,

>

> - Anton

>

>

> !DSPAM:451,4bc835a5518712071889376!

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Re: What if the user closes the browser while INSERT INTOMySQL? (PHP/MySQL)

On Fri, 16 Apr 2010 11:44:42 +0200, Jørn Dahl-Stamnes

wrote:



> The server does not know if the browser is closed or not (or if the

> network

> connection is losted). It will continue to execute the code until

> finnished.



Not quite true. If it decides to flush its output buffer and notices that

there's no-one around to receive the output, the process may well be

terminated.



As long as you do not echo(), print() or flush() to a closed connection,

you're probably going to be fine.



/ Carsten

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Re: What if the user closes the browser while INSERT INTO MySQL?

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Well... just summarizing my thread here.

I tested this today.

As Carsten mentioned...

Without the function 'ignore_user_abort(true);', when the browser is
closed the script will stop at some point (if there's output ('echo etc') o=
f
certain number (1,000s) of characters remaining.).

Many Thanks to Carsten!!


On Fri, Apr 16, 2010 at 9:33 PM, Carsten Pedersen wrot=
e:

>
> On Fri, 16 Apr 2010 11:44:42 +0200, J=F8rn Dahl-Stamnes
> wrote:
>
> > The server does not know if the browser is closed or not (or if the
> > network
> > connection is losted). It will continue to execute the code until
> > finnished.
>
> Not quite true. If it decides to flush its output buffer and notices that
> there's no-one around to receive the output, the process may well be
> terminated.
>
> As long as you do not echo(), print() or flush() to a closed connection,
> you're probably going to be fine.
>
> / Carsten
>
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> MySQL General Mailing List
> For list archives: http://lists.mysql.com/mysql
> To unsubscribe:
> http://lists.mysql.com/mysql?unsub=3Dphp.antonio@gmail.com
>
>

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Re: What if the user closes the browser while INSERT INTO MySQL?

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On Fri, Apr 16, 2010 at 1:31 PM, Nigel Wood wrote:

> P.S. Sorry to the other list users for a PHP oriented discussion.
>

Get a room, you two :-)

--
Bier met grenadyn
Is als mosterd by den wyn
Sy die't drinkt, is eene kwezel
Hy die't drinkt, is ras een ezel

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Re: What if the user closes the browser while INSERT INTO MySQL?

On this level, it's more of an apache/web-server-in-general issue.

There are 2 connections to be considered here: the connection between
the browser and the web server and the connection between the
webserver (running PHP for example) and the database and they have
very different behaviours.

If the connection is lost between the web server and the database, the
connection will abort and any pending uncommited operations are rolled
back.

If the connection is lost between the browser and the webserver, that
is another matter. Generally, webservers do not notify server-side
applications of that connection abort so that code will continue to
completion with it's output being lost to the ether. As the
application is not notified of the disconnect; the database server
never hears about it and continues to do as requested.

So: connection lost between browser and webserver affects nothing
except the browser... Should the server-side application itself
abort, uncommited changes will be lost.


On Mon, Apr 19, 2010 at 8:36 AM, Johan De Meersman wrote:
> On Fri, Apr 16, 2010 at 1:31 PM, Nigel Wood wrote:
>
>> P.S. Sorry to the other list users for a PHP oriented discussion.
>>
>
> Get a room, you two :-)
>
> --
> Bier met grenadyn
> Is als mosterd by den wyn
> Sy die't drinkt, is eene kwezel
> Hy die't drinkt, is ras een ezel
>



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- mdykman@gmail.com

May the Source be with you.

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