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CXIII. Zlib Komprimierungsfunktionen
Diese Extension nutzt die Funktionen der von Jean-loup Gailly und Mark Adler
um transparent gzip (.gz) - komprimierte Dateien lesen und
schreiben zu k�nnen. Es muss die zlib >= 1.0.9 verwendet werden,
um die Funktionen nutzen zu k�nnen.
Diese Extension beinhaltet Versionen der meisten Dateisystem-Funktionen, die mit
gzip-komprimierten (und nicht komprimierten) Datein, jedoch nicht
mit Sockets funktionieren.
Anmerkung:
Mit Version 4.0.4 wurde ein fopen-wrapper f�r .gz-Dateien
eingef�hrt, so das eine spezielle 'zlib:'-URL verwendet werden kann,
um komprimierte Datei transparent �ber die f*()-Dateifunktionen
genutzt werden k�nnen.
In Version 4.3.0 wurde diese spezielle Prefix in zlib:// ge�ndert,
um Konflikte mit Dateinamen zu vermeiden die ':' enthalten.
Dieses Feature erfordert eine C-Laufzeitbibliothek, die
die fopencookie()-Funktion bereitstellt. Nach
aktuellem Stand ist die GNU libc die einzige Bibliothek, die dieses
Feature bereitstellt.
Code-Beispiel
�ffnet eine tempor�re Datei und schreibt einen Test-String in die
Datei, dann wird der Inhalt dieser Datei zweimal ausgegeben.
Beispiel 1. Zlib Beispiel <?php
$filename = tempnam ('/tmp', 'zlibtest').'.gz';
print "<html>\n<head></head>\n<body>\n<pre>\n";
$s = "Only a test, test, test, test, test, test, test, test!\n";
// �ffne eine Datei zum Schreibzugriff mit der maximalen Kompressionsstufe
$zp = gzopen($filename, "w9");
// Schreibe den String in die Datei
gzwrite($zp, $s);
// Schlie�e die Datei
gzclose($zp);
// �ffne die Datei zum Lesezugriff
$zp = gzopen($filename, "r");
// Lese 3 Zeichen
print gzread($zp, 3);
// Gebe den Inhalt aus, bis die Datei vollst�ndig ausgegeben ist.
gzpassthru($zp);
print "\n";
// �ffne die Datei und gebe den Inhalt zum zweiten Mal aus
if (readgzfile($filename) != strlen($s)) {
echo "Fehler in den Zlib-Funktionen!";
}
unlink($filename);
print "</pre>\n</h1></body>\n</html>\n";
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- Inhaltsverzeichnis
- gzclose -- Close an open gz-file pointer
- gzcompress -- Compress a string
- gzdeflate -- Deflate a string
- gzencode -- Create a gzip compressed string
- gzeof -- Test for end-of-file on a gz-file pointer
- gzfile -- Read entire gz-file into an array
- gzgetc -- Get character from gz-file pointer
- gzgets -- Get line from file pointer
- gzgetss --
Get line from gz-file pointer and strip HTML tags
- gzinflate -- Inflate a deflated string
- gzopen -- Open gz-file
- gzpassthru --
Output all remaining data on a gz-file pointer
- gzputs -- Alias for gzwrite()
- gzread -- Binary-safe gz-file read
- gzrewind -- Rewind the position of a gz-file pointer
- gzseek -- Seek on a gz-file pointer
- gztell -- Tell gz-file pointer read/write position
- gzuncompress -- Uncompress a deflated string
- gzwrite -- Binary-safe gz-file write
- readgzfile -- Output a gz-file
User Contributed Notes
Zlib Komprimierungsfunktionen |
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monte at ispi dot net
19-Apr-2001 01:02 |
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An alternate way to handle gzip compression is to let the mod_gzip module
of apache handle it. This seems to contradict the tutorial on
phpbuilder.com saying that it won't compress php (or any dynamic) output,
but mod_gzip as of version 1.3.17.1a works well for me.
Here is
an example of an httpd.conf setup:
<IfModule
mod_gzip.c>
mod_gzip_on Yes
mod_gzip_dechunk
Yes
mod_gzip_minimum_file_size
300
mod_gzip_maximum_file_size 0
mod_gzip_maximum_inmem_size
100000
mod_gzip_keep_workfiles No
mod_gzip_temp_dir
/tmp
mod_gzip_item_include file
\.html$
mod_gzip_item_include file
\.jsp$
mod_gzip_item_include file
\.php$
mod_gzip_item_include file
\.pl$
mod_gzip_item_include mime
^text/.*
mod_gzip_item_include mime
^application/x-httpd-php
mod_gzip_item_include mime
^httpd/unix-directory$
mod_gzip_item_include handler
^perl-script$
mod_gzip_item_include handler
^server-status$
mod_gzip_item_include handler
^server-info$
mod_gzip_item_exclude mime
^image/.*
</IfModule>
This will automatically compress
all output of your files with the .php extention or the x-httpd-php mime
type. Be sure to have dechunk set to Yes.
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STEVE vortexx at freemail dot hu
20-Jan-2003 12:33 |
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The manual here states that the option zlib.output_compression can be
changed at runtime using ini_set:
Name Default Changeable
zlib.output_compression "Off" PHP_INI_ALL
(!)
zlib.output_compression_level "-1" PHP_INI_ALL
zlib.output_handler "" PHP_INI_ALL
However, using
PHP 4.3.0 on Win2k this is not so. Trying to set zlib.output_compression
to "On" from within a PHP script returns empty (meaning ini_set
was unsuccessful)!
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mlevy at rgj dot com
12-Feb-2003 09:06 |
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If you turn zlib.output_compression_level on, be advised that you shouldn't
try to flush() the output in your scripts. PHP will add the gzip header
but send the output uncompressed, which plays havoc with Mozilla. IE seems
to handle it, though.
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wallacebw at yahoo dot com
09-Mar-2003 03:10 |
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I have found that using:
zlib.output_compression = on (or On)
instead of using a chunk size (i.e. 4KB)
is problematic
when used in conjunction with output buffering i.e. 'ob_start()' and form
data. PHP intermittently fails to return any data to client after
processing form.
Using a chunk size appears to correct this
problem.
Brian Wallace
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phpuser at dpiworld.com
21-Mar-2003 02:32 |
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With zlib.output_compression turned on in the php.ini file, I discovered
that the output of my script which returns jpeg data was being compressed,
which for some reason causes IE 6.0 to take much longer to display the
image. Turning off compression cured the problem. So I tried calling
ini_set("zlib.output_compression", 0 ) (also tried
"Off")
as the first statement in my script. It does not
appear to work. Then I noticed that the documentation is inconsistant,
here it says zlib.output_compression can be changed anywhere
(PHP_INI_ALL), yet in the docs for ini_set() it says that it can only be
changed in PHP_INI_SYSTEM or PHP_INI_PERDIR. If I understand correctly
that means ini_set() can't change it in a script. Apparently the latter
is true.
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devcontact at tech-island dot com
24-Mar-2003 02:47 |
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The method of first reading the source file and then passing its content to
the gzip function instead of simply the source and destination filename
was a bit confusing for me.
So I have written a simple funtion you
can use to compress files in the gzip format (gzip is readable by winzip
like .zip files)
function compress($srcName, $dstName)
{
$fp = fopen($srcName, "r");
$data = fread ($fp,
filesize($srcName));
fclose($fp);
$zp = gzopen($dstName,
"w9");
gzwrite($zp, $data);
gzclose($zp);
}
// Compress a
file
compress("/web/myfile.dat", "/web/myfile.gz");
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PHP Handbuch
Funktionsreferenz
Apache
zip_read