How to read and add to an array then write it to a text file

[npm]

I'm setting up a polling system where voters can only vote once, based on their IP address.

When the poll loads I want to open the text file with the list of blocked IPs to see if a voter has already voted. If not, they vote and then their IP should get added to the array and then the updated array get written back to the text file.

Here's the code I have so far:

<?php
// Get information from file //
$IPs = "IPs.txt";
$fp = fopen($IPs, "r");
$ipList = fread($fp, filesize($IPs));
fclose($fp);

// Explode line breaks //
$bannedIPs = explode("\n", $ipList);

// Check for IP //
if (in_array($ipNew, $ipList)) {
	echo "Thanks! We've already counted your vote.";
}
else {
	include("voteCode.php");
}

// Get new IP //
$ipNew = $REMOTE_ADDR;
echo "Your IP: " . $ipNew . "<br />";

// Add new IP to array //
$bannedIPs[] = $ipNew;

// Write new array & close file //
$fp = fopen("IPs.txt","w+");
foreach($bannedIPs as $key => $value){
	fwrite($fp,$value."\n");
}
fclose($fp);
?>

I think I have it worked out until the point where I need to write the updated array, and then it's not working.

Thanks!

[Dormilich]

hm, wouldn’t it be easier to put the IPs into a database (esp. if you have thousands of IPs)? it would make adding/checking much easier.

PS. won’t work, if the user has a dynamic IP.

[npm]

The thing is that I'll be initially setting up over 100 separate polls (with more to come) and I'll need a text file for each poll to store the IPs of the voters.

I know about the dynamic IP thing. It's not too big of a deal. This will just be to keep most people from voting a bunch of times on the same poll.

[npm]

Well, now I've made some progress, but it's not quite there.

<?php
// Get information from file //
$IPs = "IPs.txt";
$fp = fopen($IPs, "r");
$ipList = fread($fp, filesize($IPs));
fclose($fp);

// Explode line breaks //
$bannedIPs = explode("\n", $ipList);

// Get new IP //
$ipNew = $REMOTE_ADDR;

// Check to see if IP is in list
if (in_array($ipNew, $bannedIPs)) {
	echo "Thanks! We've already counted your vote.";
}
else {
	include("voteCode.php");
}

// Add new IP to array //
array_push($bannedIPs, $ipNew);

// Write new array & close file //
$fp = fopen("IPs.txt", "w+");
foreach($bannedIPs as $key => $value) {
	fwrite($fp,$value . "\n");
}
fclose($fp);
?>

I've gotten it to add the new IP to the list, and write the file, but if I started with this original text file:

11.111.11.111
22.222.22.222
33.333.33.333
44.444.44.444
55.555.55.555

It will save the text file like this:

11.111.11.111
22.222.22.222
33.333.33.333
44.444.44.444
55.555.55.555
66.666.66.666

77.777.77.777

88.888.88.888

99.999.99.999

etc.

Instead of this:

11.111.11.111
22.222.22.222
33.333.33.333
44.444.44.444
55.555.55.555
66.666.66.666
77.777.77.777
88.888.88.888
99.999.99.999
etc.

So, it's sorta doing what I want, but not quite exactly.

[captainB]

database

so, why won't you use a database again? It seems to make sense to use one. you can have a polls table, a banned IPs table, and a 3rd table that ties them together. You would even get voting statistics this way, if you wanted.

As for the text file, just by looking at your post, it seems like your new IPs contain a newline character which gets added.
What would happen if you were to add the new IP directly to the end of the text file, instead of adding it to the array and re-writing the entire file every time a vote is made?

I still think a database is much better here.
I'd be happy to help you create one =)