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Posted by Tom Rogers on 10/04/60 11:11
Hi,
Friday, March 11, 2005, 6:30:52 PM, you wrote:
KM> -----Original Message-----
KM> From: Richard Lynch [mailto:ceo@l-i-e.com]
KM> Sent: Thursday, March 10, 2005 10:14 PM
KM> To: Ross Hulford
KM> Cc: php-general@lists.php.net
KM> Subject: Re: [PHP] incrementing a number from a text file
>>> I want to read a number from an external (txt) file and increment it.then
>>> save the number back on the text file.
>>> I know this is possible but want a simple amd economical way to do this.
>> That's what you *THINK* you want to do :-)
>> But what happens when *TWO* users hit that same script at exactly the same
>> time.
KM> <snip>
>> This is why so many early "hit counter" scripts back in the day were
>> always getting messed up and reset to 0.
KM> Don´t increase if counter is not read?
>> What you really want, almost for sure, is an SQL database with "sequences"
KM> I try NOT to use databases if not nessecary
>> You *can* use http://php.net/flock, but even that is a Bad Idea, because
>> flock under Un*x is self-imposed -- If some *other* program/script/user
>> decides not change that file and doesn't use flock, well, they're not
>> STOPPED from doing that.
KM> Poor programming?
>> flock is therefore all too subject to human fallibility when you re-work,
>> re-write, or add more code to your system.
KM> Every code is... if You don´t use Your head, the outcome will be...?
KM> If U no nothing about SQL, I use a database to a counter, I
KM> get a piece of code from a friend "alter table counter
KM> auto_increment = 1"; and I´m curious to see, what it does?
KM> Or better: I put my query in a link like <a
KM> href="db.php?q=select+*+from+customers">show customers</a> and
KM> I´ve got NO clue about the settings in the mysql db, so this gets
KM> "funny"
KM> <a href="db.php?q=delete+from+customers">show customers</a>
KM> <a href="db.php?q=drop+table+customers">show customers</a>
KM> *whistle*
KM> This _was_ an issue in a company I worked for, along with queries like:
KM> Select blablabla FROM t1,t2,t3
KM> WHERE customers LIKE '%$s%'
KM> OR name LIKE '%$s%'
KM> OR domain LIKE '%$s%'
KM> OR email LIKE '%$s%'
KM> OR log LIKE '%$s%'
KM> AND t1.id = t2.t1_id
KM> AND t1.id = t3.t1_id
KM> Horror!
KM> Kind regards
KM> Kim Madsen
KM> --
KM> PHP General Mailing List (http://www.php.net/)
KM> To unsubscribe, visit: http://www.php.net/unsub.php
Sorry to get in late here, try these scripts (probably unix only):
//count.php
<?php
//wait if another process has results.new
$x = 5; //5 seconds
while($x > 0 && file_exists('results.new')){
sleep(1);
clearstatcache();
$x--;
}
if($x == 0) echo "Hung process detected <br>";
if(file_exists('results')){
$count = intval(trim(file_get_contents('results')));
$count ++;
}else{
$count = 1;
}
$fp = fopen("results.new", "w");
if($fp) {
fwrite($fp,$count."\n");
exec("ln -f results results.old"); //incase it is being read
exec("mv results.new results");
echo "done count=$count\n";
fclose($fp);
}
//testing script count.html
<html>
<head>
<title>Counter Test</title>
</head>
<frameset cols="150,150,150,*" rows="*">
<frame src="count.php" name="c1" frameborder="1">
<frame src="count.php" name="c2" frameborder="1">
<frame src="count.php" name="c3" frameborder="1">
<frame src="count.php" name="c4" frameborder="1">
<noframes>
<body bgcolor="#FFFFFF">
<p>need frames</p>
</body>
</noframes>
</frameset>
</html>
In theory no 2 frames should have the same number....
--
regards,
Tom
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