Self-extracting PHP archive

The __halt_compiler(); function in php enables to store some additional data in a php-file without blowing up the memory. A very nice possibility is to use this for a self-extracting php file as installation-packages of your php application. A wile ago I created a script which automatically creates such a archive and I think you might like it….for the impatient ones: Download / Download as Zip.

Before I start to show how the entire script works I’d like to show you a small example so that you can see how the __halt_compiler(); function can be used to store some data at the end of a file:

$fp = fopen(__FILE__, ‘r’);
fseek($fp, __COMPILER_HALT_OFFSET__);
$i=0;
while($buffer = fgets($fp)) {
    echo ($i++). “:”. $buffer.“<br></br>”;
};
__HALT_COMPILER();Line 1
Line 2
Line 3
Last line 

The first thing you might mention is, that the closing “?>” is missing, but since the function-name is nearly self-explaining you should realize very fast what the output of the script might be ;)

If that’s working the question is what’s needed for a script which is meant to create and extract a archive? The first thing is a way to create the archive itself. I used the PHP-builtin ZipArchive for that. The second thing is a script which is able to extract this archiv (using the method show above). That’s handled by the following snippet:

try {
    $zipfilename = md5(time()).‘archive.zip’; //remove with tempname()
    $fp_tmp = fopen($zipfilename,‘w’);
    $fp_cur = fopen(__FILE__, ‘r’);
    fseek($fp_cur, __COMPILER_HALT_OFFSET__);
    $i=0;
    while($buffer = fread($fp_cur,10240)) {
        fwrite($fp_tmp,$buffer);
    }
    fclose($fp_cur);
    fclose($fp_tmp);
    $zipfile = new ZipArchive();
    if($zipfile->open($zipfilename)===true) { 
        if(!$zipfile->extractTo(‘.’)) throw new Exception(‘extraction failed…’);
    } else throw new Exception(‘reading archive failed’);
    $zipfile->close();
    unlink($zipfilename);
} catch (Exception $e) {
    printf(“Error:<br></br>%s<br>%s>”,$e->getMessage(),$e->getTraceAsString());
};
__HALT_COMPILER();[zipdata is appended here later] 

As you see that’s no rocket-science just read the data, pass it to the ZipArchive object via a temporary file and extract the archive. If that’s working then you need a script which brings the PHP extraction script and the zip-data together. And since we want to have a single script for the creation of our self extracting php archive, it would be very odd if we’d place the “template” for the extraction in a separate file. That’s the reason why I just use the same method as above for this script and this time the data is php code instead of zip-data:

try {
    $sourcefolder = ‘compressthis/’;                 // maybe you want to get this via CLI argument …
    $targetname = ‘phparchive.php’;                    
    $zipfilename = md5(time()).‘archive.zip’;         // replace with tempname()

    // create a archive from the submitted folder
    $zipfile = new ZipArchive();
    $zipfile->open($zipfilename,ZipArchive::CREATE);
    addFiles2Zip($zipfile,$sourcefolder,true);
    $zipfile->close();

    // compile the selfextracting php-archive
    $fp_dest =fopen($targetname,‘w’);    
    $fp_cur = fopen(__FILE__, ‘r’);
    fseek($fp_cur, __COMPILER_HALT_OFFSET__);
    $i=0;
    while($buffer = fgets($fp_cur)) {
        fwrite($fp_dest,$buffer);
    }
    fclose($fp_cur);
    $fp_zip = fopen($zipfilename,‘r’);
    while($buffer = fread($fp_zip,10240)) {
        fwrite($fp_dest,$buffer);
    }
    fclose($fp_zip);
    fclose($fp_dest);
    unlink($zipfilename);

} catch (Exception $e) {
 echo $e->getTraceAsString();
}

function 
addFiles2Zip(ZipArchive $zip,$path,$removeFirstFolder=false) {
    $d = opendir($path);
    while($file = readdir($d)) {
        if ($file == “.” || $file == “..”) continue;
        $curfile=($removeFirstFolder)?substr($path.$file,strpos($path,‘/’)+1):$path.$file;
        if(is_dir($path.$file)) {
            $zip->addEmptyDir($curfile);
            addFiles2Zip($zip,$path.$file.‘/’,$removeFirstFolder);    
        } else {
            $zip->addFile($path.$file,$curfile);
        }    
    }
    closedir($d);
}


__HALT_COMPILER();[the script shown above]

If you all wrap up into a single script the you’ll have something like the script I already mentioned. I think that it could be useful to have a version with a better error-handling and maybe also some CLI functions so that there’s no need to edit the script itself everytime… I’ll keep you updated as soon as I have something like that :)