Zlib 函数
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PHP手册

gzread

(PHP 4, PHP 5)

gzread — Binary-safe gz-file read

说明

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.

参数

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.

返回值

The data that have been read.

范例

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);
?>

参见

Zlib 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: Binary-safe gz-file read

用户评论:

calin_ip at yahoo dot com (10-Nov-2010 11:55)

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 05:00)

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 (11-Jun-2009 05:21)

<?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 10:18)

<?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 09:31)

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 11:06)

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 08:33)

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.