gzread

(PHP 4, PHP 5)

gzread — Binary-safe gz-file read

Description

string gzread ( resource $zp , int $length )

gzread() reads up to length bytes from the given gz-file pointer. Reading stops when length (uncompressed) bytes have been read or EOF is reached, whichever comes first.

Parameters

zp: The gz-file pointer. It must be valid, and must point to a file successfully opened by gzopen().
length: The number of bytes to read.

Return Values

The data that have been read.

Examples

Example #1 gzread() example


<?php
// get contents of a gz-file into a string
$filename = "/usr/local/something.txt.gz";
$zd = gzopen($filename, "r");
$contents = gzread($zd, 10000);
gzclose($zd);
?>


Regarding finding out the lenght of the gz file.

For some reason the seek() function didn't worked, so, I've tried finding out the last 4 bytes using string functions.

That worked pretty well. Here is the code. 

<?php

$stringu='my_beautiful_file.txt.gz';

$gzip=file_get_contents($stringu);

$rest = substr($gzip, -4); 

$GZFileSize = end(unpack("V", $rest));



$FileRead = $stringu;

$HandleRead = gzopen($FileRead, "rb");

$ContentRead = gzread($HandleRead, $GZFileSize);

gzclose($HandleRead);

?>

denis at bitrix dot ru 16-Jul-2010 09:00


Note that this functions' behavior differs from fread in case of EOF.



When you read the last chunk (mean the last bytes from file), it is EOF just after gzread, but in case of fread you need to read once more to get EOF.



Hope, I am clear :)

robinv12001 at yahoo dot co dot in 10-Jun-2009 09:21


<?php

//Extracting the content of a gzip file in php and creating a new csv file using the content

//Create a folder uploads inside current folder

$local_file    =    'test.gz';



//To Get the size of the uncompressed file

$FileRead = $local_file;

$FileOpen = fopen($FileRead, "rb");

fseek($FileOpen, -4, SEEK_END);

$buf = fread($FileOpen, 4);

$GZFileSize = end(unpack("V", $buf));

fclose($FileOpen);

//To Get the size of the zip file



$fzip_size    =    $GZFileSize;

    

$filename    =    $local_file;

$ext        =    pathinfo($filename,PATHINFO_EXTENSION);    

$file_name    =    pathinfo($filename,PATHINFO_FILENAME);        

$file_name    =    $file_name.".csv";



$zd         =     gzopen($filename, "rb");

$contents     =     gzread($zd, $fzip_size);

gzclose($zd);

$file_name    =    "uploads/".$file_name;

$fp    =    fopen($file_name, "wb");

fwrite($fp, $contents); //write contents of feed to cache file

fclose($fp);

if(file_exists($file_name))

{

    chmod($file_name,0755);

    unlink($local_file);

}

?>

robinv12001 at yahoo dot co dot in 09-Jun-2009 02:18


<?php


//Using FTP Download a gzip file on current date from a remote server


//The gzip files are extracted


function parse_rawlist( $array )


{


    $i=0;


    foreach($array as $curraw)


    {


        $struc = array();


        $current = preg_split("/[\s]+/",$curraw,9);





        $struc['perms']      =     $current[0];


        $struc['number']     =     $current[1];


        $struc['owner']     =     $current[2];


        $struc['group']      =     $current[3];


        $struc['size']         =     $current[4];


        $struc['month']      =     $current[5];


        $struc['day']        =     $current[6];


        $struc['time']      =     $current[7];


        $struc['zfile_name']      =     $current[8];


     $structure[$i]      =     $struc;


    $i++;


    }


   return $structure;





}


ini_set('memory_limit', '100M');





//Give FTP Information Here


//------------------------------------------------------------


$ftp_server     =     "example.com";


$ftp_user_name    =    "example";


$ftp_user_pass    =    "test";


//------------------------------------------------------------


//------------------------------------------------------------


$local_path     =    '/opt/lampp/htdocs/sample/test.gz';//Local Path


$server_path     =     'outgoing/folder/';//Remote Sever Path


//------------------------------------------------------------





$conn_id = ftp_connect($ftp_server,21);


if($conn_id)


{


    echo "Successfully connected";


}


  


$login_result     =     ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);


ftp_chdir($conn_id, $server_path);//Change Current Working Directory


$file_list     =    ftp_rawlist($conn_id,".");


$zip_details    =    parse_rawlist($file_list);


set_time_limit(1000); 


$curr_date    =    strtotime(date("F d Y"));


for($i=0;$i<count($zip_details);$i++)


{


    $fname        =    $zip_details[$i]['zfile_name'];    


    $mod_date1    =    $zip_details[$i]['month']." ".$zip_details[$i]['day']." ".date("Y");    


    $mod_date    =    strtotime($mod_date1);//File Modified Date


    if($mod_date == $curr_date)//If modified date equals current date


    {


        $local_file    =    $fname;


        $server_file    =    $fname;


        if (ftp_get($conn_id, $local_file, $server_file, FTP_BINARY)) 


        {


        


            echo "<br/>Successfully written to $local_file\n";


        } 


        else 


        {


            echo "<br/>There was a problem\n";


        }


        if(file_exists($local_file))


        {


            $fzip_size    =    $zip_details[$i]['size'];    


            $filename    =    $local_file;


            $ext        =    pathinfo($filename,PATHINFO_EXTENSION);    


            $file_name    =    pathinfo($filename,PATHINFO_FILENAME);        


            $file_name    =    $file_name.".csv";


            $zd         =     gzopen($filename, "r");


            $contents     =     gzread($zd, $fzip_size);


            $file_name    =    "uploads/".$file_name;


            file_put_contents($file_name,addslashes($contents));


            if(file_exists($file_name))


            {


                chmod($file_name,0755);


                unlink($local_file);


            }


            gzclose($zd);


        }


    }


}


ftp_close($conn_id);


?>

utku 08-Feb-2008 01:31


I don't think it would be wise to open a whole gzip file (it _is_ compressed for a reason, and likely to be a very big file) into a single string. You would most likely hit the php memory limits. Instead, if you need to process the file, put your gzread calls in a loop, and read incrementally by a setting $length to a constant value.

zaotong at yahoo dot com 07-Mar-2007 03:06


As was shown to me in another forum there is a way to get the uncompressed size of the gz file by viewing the last 4 bytes of the gz file.



Here is a piece of code that will do this

<?php

$FileRead = 'SomeText.txt';

$FileOpen = fopen($FileRead, "rb");

        fseek($FileOpen, -4, SEEK_END);

        $buf = fread($FileOpen, 4);

        $GZFileSize = end(unpack("V", $buf));

        fclose($FileOpen);

        $HandleRead = gzopen($FileRead, "rb");

        $ContentRead = gzread($HandleRead, $GZFileSize);

?>



This will read the last 4 bytes of the gz file and use it as the file int for the gzread.



Thanks to stereofrog for helping me with this code.

methatron at hotmail dot com 27-Sep-2006 12:33


Be aware that gzread's second parameter - length reffers to the file's uncompressed size, therefore using this code:



<?php

$file_name = "/usr/local/something.txt.gz";

if($file_handle = gzopen($file_name, "r"))

{

    $contents = gzread($file_handle, filesize($file_name));

    gzclose($file_name);

}

?>



will probably truncate the content of the file as filesize checks for the file's compressed size.

So either use the actual uncompressed size, if you know it, or use an aribtrary big enough length, as gzreading will stop at the end of the file anyway.

add a note

gzread

Description

Parameters

Return Values

Examples

See Also