Telling the script to only run once? Can I?

[darthmahon]

Hi,

I've just settled some code issues with a file download script and now I need to take it to the next level.

I have a list of names and addresses, the query selects say 400 of these and puts them in a .csv file and initatiates a file download. Now, how do I stop the users from pressing refresh and getting another 400 users? They are going to have to pay for it so I don't want them getting as many names and addresses as they want.

Here is the code as I have it:

<?php

mysql_connect(localhost, nn, nn);
mysql_select_db(nn);

$download_me = $_GET['download_me']; 
if($download_me) { 

   $date = date("Ymd");
   $name= "$date";
   // make browser output downloadable 
   header("Content-type: application/octet-stream");  
   header("Content-Disposition: attachment; filename=$name.csv");  
   header("Content-Transfer-Encoding: binary"); 

   $result = mysql_query("SELECT id, firstname, lastname, email FROM userstest WHERE registered=1 ORDER BY RAND(id) LIMIT 400"); 

   $formsubmit="1";

   while($row = mysql_fetch_object($result)) { 
	   //$query = "DELETE FROM userstest WHERE id=' ".$row->id." ' ";
	   //print $query;
	   $array = array(" $row->email, $row->firstname, $row->lastname ");
	   $line = implode(",", $array) ."\n"; 
	   print $line;
	   //mysql_query ("UPDATE userstest SET registered='2' WHERE id=' ".$row->id." ' ");echo mysql_error();
   } 
   // this stuff is being downloaded; stop here before default stuff is printed 

   //mysql_query ("DELETE FROM userstest WHERE registered=2");echo mysql_error();

   die;
}

if ($formsubmit!="") { $formsubmit="";

printf("<div>You have already downloaded this file!</div>");

} else {

$result = mysql_query("SELECT id, firstname, lastname, email FROM userstest WHERE registered=1 ORDER BY RAND(id) LIMIT 400");
if (mysql_num_rows($result) < 400)
{
		printf("<div>Not enough files</div>"); 
}
else
{
		printf('
		<div>Click here to <a href=\'?download_me=true\'>download</a> registered users</div>'
		); 
}

}

?>

Any ideas? I tried putting in a hidden variable $formsubmit and then trying to catch it when they tried again but obviously it's not working as I can refresh as many times as I like.

[HalfaBee]

Update a column in your DB to indicate they have done the download and use it in the WHERE statement.

HalfaBee

[darthmahon]

Can't I just assign something to a variable once the download is initiated and then check the variable.

If it has something in it, don't allow it to download.

If it doesn't have something, let it download.

I've tried this with $formsubmit variable but it's not working.

Having to update the DB would be a pain. What happens when they want to download a different file and I check against the record and it says they have already downloaded a file, but it was the old one?

[HalfaBee]

You can't expect variables to remain valid on a reload.

Having to update the DB would be a pain. What happens when they want to download a different file and I check against the record and it says they have already downloaded a file, but it was the old one?

If you are running a bussiness don't penny pinch, otherwise someone will rip you off big time.

If they pay for it you should be keeping a track of that, so create a table using the invoice number as the id and a flag to indicate that they have received the information.

Updating the DB should not be that hard

mysql_query( "UPDATE tracking SET invoice_num=1234, file_rec=1" );
where tracking is your new table name.

HalfaBee

[fandelem]

halfabee is correct to a point: use the database. set a flag, check the flag before initiating the download. this is a failsafe way.

there is an alternative if you do not wish to do this: create a session, set a session variable, and then check the session variable before initiating a download. sound familiar to the above option? hummm....

i'd say go for the first (database) option unless it's not feasible. the second option would work up until the point the person closed the browser and opened a new browser. a cookie would be a third option which would remain until a savvy client deleted his/her cookies...

cheers,

k.