Generate dummy files

mofle

I'm trying to create a dummy file generator in PHP, but with no luck. I need the generated files to have some kind of scrambled content, and I need to be able to set the size of the generated file, and the extension. I think it has something to do with the fwrite(), but I'm a PHP noob.

I would really appreciate some help on this 😉

slick101

You need to create the file first

$ext = '.txt';
$filename  = 'wow';
$fh = fopen($filename . $ext, 'w');

fwrite($fh, 'scrambled_content');

fclose($fh);

not sure how to setup certain size of the file on creation. check up on filesize();

laserlight

Besides the traditional fopen(), fwrite() and fclose() functions, you could simplify everything with [man]file_put_contents/man. Generating the scrambled content is easy, but you would need to define what you mean by scrambled content. Do you want something of the "Lorem Ipsum" kind, or are you looking for a string of random numbers?

mofle

Random number, preferably binary.

How would I do that, with an option to select the filesize of the file?

NogDog

If you truly want a binary file, you could do something like:

$fh = fopen('binary_file', 'wb');
fwrite($fh, sha1(uniqid('', true), true));
fclose($fh);

mofle

Thank you!

How would I create content like this?

£àŒ∑aO˙BU_WˇøvÂœwç<k‘u Ø(e_ˇl≥Ωƒ⁄≠!‡âäaLÿÄãO\sè'Eù4¬l˜ÿ(˘C£Rö\ÿARx≤Œ,ÊPjíØ†9B¬ˇSZâµ],Q“zrGO?‰¬§∆πõ»ß™)3˘ÓEﬁU>FA“—S⁄å"õÂÇ–£÷u°»VÇNb›¿Jd«ö◊b&#8734😉‚–t¬&≤P[%ú‰ÁÑiT√º“˚gÊØ ö÷»dÔa.~g†^{"e±'GÑŸÛAW5Û—mÓsÕÒFéyºlH;¥˘q⁄Êä”Ö´¡òé?RyLT≠ò5`Ì…çp∏äsÔΩ3+°Æ¸M?Ê]}

formlesstree4

Doesn't PHP have a random function like rand()? Or is that BASIC I'm thinking about?

NogDog

formlesstree4;10882467 wrote:
Doesn't PHP have a random function like rand()? Or is that BASIC I'm thinking about?

[man]rand/man

NogDog

If you just want a random number of ASCII characters (untested):

function randomText($length=1)
{
   $length = (int)$length;
   $result = '';
   for($i=0; $i < $length; $i++)
   {
      $result .= chr(rand(0,255));
   }
   return $result;
}
file_put_contents($filename, randomText(100));

mofle

How would I generate random unicode character?

mofle

Here's how I've gotten so far. I'm having some problems with $content.

How can I have the random character written to the $content variable?

<?php

$content = null;
$size = $_GET['size'];
$filename = $_GET['filename'] . "." . $_GET['extension'];

$content = for ($i = 0; $i < $size; $i++) {
    chr(rand(0,255))
}


if ($extension == "doc") {
	header("Content-type: application/msexcel");
	header("Content-Disposition: attachment; filename=$filename");
	header("Pragma: no-cache");
	header("Expires: 0");
	print "$header\n$content";

}
elseif ($extension == "txt") {
	header("Content-type: application/msword");
	header("Content-Disposition: attachment; filename=$filename");
	header("Pragma: no-cache");
	header("Expires: 0");
	print "$header\n$content";
}

?>

laserlight

What you have right now might work, except that you need to fix the for loop to something like:

$content = '';
for ($i = 0; $i < $size; $i++) {
    $content .= chr(rand(0, 255));
}

mofle

Thanks, but it doesn't work. Nothing happens when I implement your code.

My current code:

<?php

$size = $_GET['size'];
$filename = $_GET['filename'] . "." . $_GET['extension'];
$content = '';

for ($i = 0; $i < $size; $i++) {
    $content .= chr(rand(0, 255));
}

if ($extension == "doc") {
	header("Content-type: application/msexcel");
	header("Content-Disposition: attachment; filename=$filename");
	header("Pragma: no-cache");
	header("Expires: 0");
	print "$header\n$content";

}
elseif ($extension == "txt") {
	header("Content-type: application/msword");
	header("Content-Disposition: attachment; filename=$filename");
	header("Pragma: no-cache");
	header("Expires: 0");
	print "$header\n$content";
}

?>

NogDog

Are you setting all the required parameters in the URL query string? Maybe you need an "else" after the "elseif" to indicate if neither if condition matched, perhaps doing a print_r($_GET) in it for debugging?

mofle

Doesn't help adding an "else".

print_r($_GET) gives:

Array ( [filename] => test [size] => 1024 [extension] => doc [x] => [y] => )

Any ideas?

NogDog

You never define the $extension variable, so it's null in your if/elseif conditions.

PS: Adding the following to the top of your script would have flagged it for you:

<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);

mofle

Do I really need the Content-Type header?

I tried removing the switch statement bit, and it worked.

So what's really the point of the Content-Type header if the browser detect the type based on the extension anyway?

And is there a way to make the random text generation faster?

And how can I set a max limit on the filesize?

<?php

$size = $_GET['size'];
$extension = $_GET['extension'];
$filename = $_GET['filename'] . "." . $extension;
$content = '';

for ($i = 0; $i < $size; $i++) {
    $content .= chr(mt_rand(0, 255));
}

switch($extension) {
case "xls":
 header("Content-type: application/msexcel");
break;

case "doc":
 header("Content-type: application/msword");
break;

case "txt":
 header("Content-type: application/notepad");
break;
}

header("Content-Disposition: attachment; filename=$filename");
header("Pragma: no-cache");
header("Expires: 0");
print $content;

?>

HalfaBee

Just add a test for the $size variable.

$size = $_GET['size'];
$extension = $_GET['extension'];
$filename = $_GET['filename'] . "." . $extension;
$content = ''; 

if( $size > 1024 ) {
    $size=1024;
}

Ashley_Sheridan

You were trying to use a $header variable that was not even created. I've removed that and replaced the if/elseif/else with a switch, which is a bit more flexible if you ever want to add different file types.

<?php
$size = $_GET['size'];
$filename = $_GET['filename'] . "." . $_GET['extension'];
$content = '';

for ($i = 0; $i < $size; $i++)
{
	$content .= chr(rand(0, 255));
}

switch($extension)
{
	case 'doc':
	{
		header("Content-type: application/msexcel");
		break;
	}
	case 'txt':
	{
		header("Content-type: application/msword");
		break;
	}
	default:
	{
		header("Content-type: text/html");
	}
}
header("Content-Disposition: attachment; filename=$filename");
header("Pragma: no-cache");
header("Expires: 0");
print $content;
?>

I also moved most of the header sections outside of the switch, as they were just being duplicated by your code. This means if you need to change something at a later date, it will be much easier and less prone to errors if you only need to change it once.