PHP 5.6.14 is available


(PHP 4, PHP 5)

gzopenAbre un archivo gz


resource gzopen ( string $filename , string $mode [, int $use_include_path = 0 ] )

Abre un archivo gzip (.gz) para lectura o escritura.

gzopen() se puede usar para leer un archivo el cual no esté en formato gzip; en este caso gzread() leerá directamente el archivo sin descomprimirlo.



El nombre del archivo.


Como en fopen() (rb o wb) pero también puede incluir un nivel de compresión (wb9) u una estrategia: f para datos filtrados como en wb6f, h para compresión Huffman solamente como en wb1h. (Ver la descripción de deflateInit2 en zlib.h para más información sobre el parámetro de estrategia.)


Se puede configurar este parámetro opcional en 1, si se desea buscar también el archivo en la ruta include_path.

Valores devueltos

Retorna un apuntador hacia el archivo abierto, después de eso, cualquier cosa que se lea desde este descriptor de archivo sera descomprimido de forma transparente y lo que se escriba será comprimido.

Si falla la apertura, la función retorna FALSE.


Ejemplo #1 Ejemplo de gzopen()


Ver también

  • gzclose() - Cierra el apuntador de un archivo gz abierto

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User Contributed Notes 8 notes

David Gero dave at havidave dot com
4 years ago
gzopen("php://output","wb") doesn't work on a web server, nor does fopen("compress.zlib://php://output","wb").

Here is a snippet to gzip a file and output it on the fly, without using a temporary file, without reading the file into memory, and without reading the file more than once:

= fopen($file, "rb");
if (
$fin !== FALSE) {
$fout = fopen("php://output", "wb");
    if (
$fout !== FALSE) {
// write gzip header
fwrite($fout, "\x1F\x8B\x08\x08".pack("V", filemtime($file))."\0\xFF", 10);
// write the original file name
$oname = str_replace("\0", "", basename($file));
fwrite($fout, $oname."\0", 1+strlen($oname));
// add the deflate filter using default compression level
$fltr = stream_filter_append($fout, "zlib.deflate", STREAM_FILTER_WRITE, -1);
// set up the CRC32 hashing context
$hctx = hash_init("crc32b");
// turn off the time limit
if (!ini_get("safe_mode")) set_time_limit(0);
$con = TRUE;
$fsize = 0;
    while ((
$con !== FALSE) && !feof($fin)) {
// deflate works best with buffers >32K
$con = fread($fin, 64 * 1024);
        if (
$con !== FALSE) {
hash_update($hctx, $con);
$clen = strlen($con);
$fsize += $clen;
fwrite($fout, $con, $clen);
// remove the deflate filter
// write the CRC32 value
    // hash_final is a string, not an integer
$crc = hash_final($hctx, TRUE);
// need to reverse the hash_final string so it's little endian
fwrite($fout, $crc[3].$crc[2].$crc[1].$crc[0], 4);
// write the original uncompressed file size
fwrite($fout, pack("V", $fsize), 4);
dtorop932 at hotmail dot com
10 years ago
RE dubious's comment: "Being able to read gzip streams from ftp and http is near the top of my personal wishlist at the moment..."

One way to read a gzip stream over http is to daisychain stream wrappers, e.g.:

$fp = fopen("compress.zlib://", "r");
dj8 at joesvolcano dot net
24 days ago
An OO-version of David Gero's excellent GZ File format note also on this page:


// David Gero's example: read a file and output GZ
$gz_to_out = new GZTempFile(basename($file), "php://output");
$fin = fopen($file, "rb");
$data = fread($fin, 64 * 1024)) {

// Example of building your GZ file content on the fly (temp filehandle)
$gz_custom = new GZTempFile();
foreach ( ... ) {
//  Some work
$str = ...

//  Store it in a database
$m = new MongoClient();
$gridfs = $m->selectDB('test')->getGridFS();
$id = $gridfs->storeFile($gz_custom->getReadFilehandle(), array('contentType' => 'application/x-gzip'));

GZTempFile {
$__fh = null;
$uncompressed_bytes = 0;
$filesize = null;
$gz_filter = null;
$file_hash = null;
$final_read_fh = false;
$__buffer = '';
$__buffer_len = 0;

    public function
__construct($filename = 'data', $fh = null) {
$this->__fh = is_null($fh) ? fopen('php://temp','w+') : $fh;
fwrite($this->__fh, "\x1F\x8B\x08\x08".pack("V", time())."\0\xFF", 10); // GZ file header
fwrite($this->__fh, str_replace("\0", "", basename($filename)) ."\0");  // GZ filename = data, needed???
$this->gz_filter = stream_filter_append($this->__fh, "zlib.deflate", STREAM_FILTER_WRITE, -1);
$this->uncompressed_bytes = 0;
$this->file_hash = hash_init("crc32b");

    public function
fwrite($str,$length = null) {
        if (
$this->final_read_fh ) { throw new Exception("GZTempFile has already been finalized and closed.  No more writing"); }
hash_update($this->file_hash, $str);
$this->uncompressed_bytes += strlen($str);
$this->__buffer_len += strlen($str);
$this->__buffer .= $str;
        if (
$this->__buffer_len >= 64 * 1024 ) { $this->flushBuffer(); }
    public function
flushBuffer() {
        if (
$this->__buffer_len == 0 ) { return false; }
$return = fwrite($this->__fh, $this->__buffer);
$this->__buffer_len = 0;
$this->__buffer = '';

    public function
getReadFilehandle() {       
        if ( !
$this->final_read_fh ) {
$crc = hash_final($this->file_hash, TRUE);            // hash_final is a string, not an integer
fwrite($this->__fh, $crc[3].$crc[2].$crc[1].$crc[0]); // need to reverse the hash_final string so it's little endian
fwrite($this->__fh, pack("V", $this->uncompressed_bytes), 4);

$this->filesize = ftell($this->__fh);
$this->final_read_fh = $this->__fh;
7 years ago
This worked unstable for me under high load (50+ files per second):

= gzopen ( $file, 'w9' );
gzwrite ( $gz, $content );
gzclose ( $gz );

The following works fine:

= fopen ( $file, 'w' );
fwrite ( $f, gzcompress ( $content, 9 ) );
fclose ( $f );
katzlbtjunk at hotmail dot com
7 years ago
WARNING gzopen and gzread have a major disadvantage. They makes NO checksum and NO length verification of the gzipped data and discard this valuable information. This should be documented here.
rob at digital-crocus dot com
10 years ago
dtorop932 at hotmail dot com's comments, according to my tests, is incorrect. That code wishes to download the entire file before parsing, which is inconvinient. The wget method works though.
pentek_imre at mailbox dot hu
10 years ago
Be aware that when opening a remote file on a http server the gzopen will return by default false after 120 seconds waiting to any answer.
-delete-this-part-dubious at 2xtreme dot net
13 years ago
"On the fly" gunzipping actually DOES seem to work - it just appears that only LOCAL streams/files (including php://stdin) can be accessed for some reason.  I THINK (but have not yet tested) that you could similarly gzopen "php://stdout" and pass a stream of gzipped data to the browser (when run from a web page) or console (when run standalone) through there.

I HAVE tested scripts from the command line like:

wget -q -O- | php gunzip_stuff.php

where gunzip_stuff.php would be a script that gzopened "php://stdin" and did gzgets from that stream, and it seems to work fine, but that obviously doesn't help someone wanting to grab gzipped streams from remote sites from a web-based script.

Being able to read gzip streams from ftp and http is near the top of my personal wishlist at the moment...
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