Month: March 2012

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Php file_exists, does it really exists?

“Php functions are sometimes so confusing”, I don’t know how true that is, but I just found it to be true in this very case. Php’s file_exists, a function that seems like it is made to check if a file exists or not, is the one I encountered recently.

So I created this little test for this very purpose. I created an images folder with 2 files and 1 folder. Next I used file_exists function in 3 conditions with respective relative paths, to see which of those existed.

$file1="images/two.jpeg";
$file2="images/icon/one.jpg";
$file3="images/small/icon/";

if (file_exists($file1))
    echo "File one exists";

if (file_exists($file2))
    echo "File two exists";

if (file_exists($file3))
    echo "File three exists";

To my surprise all the conditions returned true.

File one exists
File two exists
File three exists

file_exists — Checks whether a file or directory exists.

According to php.net manual:

Irrespective of existence of file, file_exists function return true even if the path provided exists, which is in accordance with php manual’s definition, it’s just the name that is confusing. So, its better to use is_file() together with file_exists() if the objective is to check if the file really exists or is_dir()to check for directory.

Cheers!

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Creating a zip file using php

Creating a zip file in php is as easy as creating them on your desktop using some zipping software. Php comes with inbuilt class that helps in making a zip file and provides all the functionality that you would ever need. Here is a simple function that I coded for my project. Hope it helps some peoples out there as well.

Php code:

// creates a compressed zip file
function create_zip($files = array(), $filename=array(), $destination = '',$overwrite = false) {
	//if the zip file already exists and overwrite is false, return false
	if(file_exists($destination) && !$overwrite) { return false; }

	//vars
	$valid_files = array();
	$valid_names = array();
	$i=0;

	//if files were passed in...
	if(is_array($files)) {
		//cycle through each file
		foreach($files as $file) {
			//make sure the file exists
			if(is_file($file)) {
				$valid_files[] = $file;
				if(isset($filename[$i]) && $filename[$i]!='') {
					$valid_names[]=$filename[$i];
				} else {
					$valid_names[]=$file;
				}
			}
			$i++;
		}
	}

	//if we have good files...
	if(count($valid_files)) {
		//create the archive
		$zip = new ZipArchive();
		if($zip->open($destination,$overwrite ? ZIPARCHIVE::OVERWRITE : ZIPARCHIVE::CREATE) !== true) {
			return false;
		}

		$i=0;
		//add the files
		foreach($valid_files as $file) {
			$zip->addFile($file,$valid_names[$i]);
			$i++;
		}

		//debug
		//echo 'The zip archive contains ',$zip->numFiles,' files with a status of ',$zip->status;

		//close the zip -- done!
		$zip->close();

		//check to make sure the file exists
		return file_exists($destination);
	} else {
		return false;
	}
}

Usage demo:

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