gzinflate

(PHP 4 >= 4.0.4, PHP 5)

gzinflateDescomprime una cadena comprimida

Descripción

string gzinflate ( string $data [, int $length = 0 ] )

Esta función descomprime una cadena comprimida.

Parámetros

data

Los datos comprimidos con gzdeflate().

length

La longitud máxima de datos a decodificar.

Valores devueltos

Los datos originales descomprimidos o FALSE en caso de error.

La función retornará un error si los datos descomprimidos son más de 32768 veces la longitud de la data de entrada o mayores que el parámetro opcional length.

Ejemplos

Ejemplo #1 Ejemplo de gzinflate()

<?php
$compressed   
gzdeflate('Compress me'9);
$uncompressed gzinflate($compressed);
echo 
$uncompressed;
?>

Ver también

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User Contributed Notes 10 notes

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15
anonymous at dekho-ji dot com
1 year ago
To decode / uncompress the received HTTP POST data in PHP code, request data coming from Java / Android application via HTTP POST GZIP / DEFLATE compressed format

1) Data sent from Java Android app to PHP using DeflaterOutputStream java class and received in PHP as shown below
echo gzinflate( substr($HTTP_RAW_POST_DATA,2,-4) ) . PHP_EOL  . PHP_EOL;

2) Data sent from Java Android app to PHP using GZIPOutputStream java class and received in PHP code as shown below
echo gzinflate( substr($HTTP_RAW_POST_DATA,10,-8) ) . PHP_EOL  . PHP_EOL;

From Java Android side (API level 10+), data being sent in DEFLATE compressed format
        String body = "Lorem ipsum shizzle ma nizle";
        URL url = new URL("http://www.url.com/postthisdata.php");
        URLConnection conn = url.openConnection();
        conn.setDoOutput(true);
        conn.setRequestProperty("Content-encoding", "deflate");
        conn.setRequestProperty("Content-type", "application/octet-stream");
        DeflaterOutputStream dos = new DeflaterOutputStream(
                conn.getOutputStream());
        dos.write(body.getBytes());
        dos.flush();
        dos.close();
        BufferedReader in = new BufferedReader(new InputStreamReader(
                conn.getInputStream()));
        String decodedString = "";
        while ((decodedString = in.readLine()) != null) {
            Log.e("dump",decodedString);
        }
        in.close();

On PHP side (v 5.3.1), code for decompressing this DEFLATE data will be
    echo substr($HTTP_RAW_POST_DATA,2,-4);

From Java Android side (API level 10+), data being sent in GZIP compressed format

        String body1 = "Lorem ipsum shizzle ma nizle";
        URL url1 = new URL("http://www.url.com/postthisdata.php");
        URLConnection conn1 = url1.openConnection();
        conn1.setDoOutput(true);
        conn1.setRequestProperty("Content-encoding", "gzip");
        conn1.setRequestProperty("Content-type", "application/octet-stream");
        GZIPOutputStream dos1 = new GZIPOutputStream(conn1.getOutputStream());
        dos1.write(body1.getBytes());
        dos1.flush();
        dos1.close();
        BufferedReader in1 = new BufferedReader(new InputStreamReader(
                conn1.getInputStream()));
        String decodedString1 = "";
        while ((decodedString1 = in1.readLine()) != null) {
            Log.e("dump",decodedString1);
        }
        in1.close();

On PHP side (v 5.3.1), code for decompressing this GZIP data will be
    echo substr($HTTP_RAW_POST_DATA,10,-8);

Useful PHP code for printing out compressed data using all available formats.

$data = "Lorem ipsum shizzle ma nizle";
echo "\n\n\n";
for($i=-1;$i<=9;$i++)
    echo chunk_split(strtoupper(bin2hex(gzcompress($data,$i))),2," ") . PHP_EOL  . PHP_EOL;
echo "\n\n\n";
for($i=-1;$i<=9;$i++)
    echo chunk_split(strtoupper(bin2hex(gzdeflate($data,$i))),2," ") . PHP_EOL  . PHP_EOL;
echo "\n\n\n";
for($i=-1;$i<=9;$i++)
    echo chunk_split(strtoupper(bin2hex(gzencode($data,$i,FORCE_GZIP))),2," ") . PHP_EOL  . PHP_EOL;
echo "\n\n\n";
for($i=-1;$i<=9;$i++)
    echo chunk_split(strtoupper(bin2hex(gzencode($data,$i,FORCE_DEFLATE))),2," ") . PHP_EOL  . PHP_EOL;
echo "\n\n\n";

Hope this helps. Please ThumbsUp if this saved you a lot of effort and time.
up
3
vitall at ua dot fm
5 years ago
The correct function for gzip and chunked data particularly when you get "Content-Encoding: gzip" and "Transfer-Encoding: chunked" headers:

<?php
function decode_gzip($h,$d,$rn="\r\n"){
if (isset(
$h['Transfer-Encoding'])){
$lrn = strlen($rn);
$str = '';
$ofs=0;
do{
   
$p = strpos($d,$rn,$ofs);
   
$len = hexdec(substr($d,$ofs,$p-$ofs));
   
$str .= substr($d,$p+$lrn,$len);
    
$ofs = $p+$lrn*2+$len;
}while (
$d[$ofs]!=='0');
$d=$str;
}
if (isset(
$h['Content-Encoding'])) $d = gzinflate(substr($d,10));
return
$d;
}
?>

Enjoy!
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2
akniep at rayo dot info
2 years ago
Take care when using the optional second parameter $length!
In our tests -at least in certain situations- we were unable to determine the actual use of this parameter, plus, it lead to the script either being unable to inflate compressed data or crash due to memory-problems.

Example:
When trying to inflate the compressed data from a website, we were literally unable to find a value (other than 0) for $length in order to make gzinflate work... while without the second parameter (or setting it to 0) gzinflate worked like a charm:

<?php
// -----------------------------------------------------------------------
// Test 1 works without problems. Memory peak usage: Before inflating: 24.787 kB; after: 24.844 kB.
gzinflate( substr($deflated_body, 10) );

// -----------------------------------------------------------------------
// ALL three of the following tests failed with a warning. Memory peak usage: Before inflating: 24.787 kB; after: 298.262 kB.
gzinflate( substr($deflated_body, 10),       200 * strlen($deflated_body) );
gzinflate( substr($deflated_body, 10),     32768 * strlen($deflated_body) );
gzinflate( substr($deflated_body, 10),     11000 );
gzinflate( substr($deflated_body, 10), 280000000 );    // the PHP memory limit was set to 300MB  (memory_limit=300M)
=>
Warninggzinflate() [function.gzinflate]: insufficient memory in [...]

// -----------------------------------------------------------------------
// The last test failed with a fatal error. Memory peak usage: Before inflating: 24.787 kB; after: ? (> 300M).
gzinflate( substr($deflated_body, 10), 300000000 );    // the PHP memory limit was set to 300MB  (memory_limit=300M)
=>
Fatal errorAllowed memory size of 314572800 bytes exhausted (tried to allocate 300000000 bytes) in
?>

In short: We were unable to determine the actual use of the second parameter in certain situations.
Be careful with using the second parameter $length!
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1
Steven Lustig
4 years ago
You can use this to uncompress a string from Linux command line gzip by stripping the first 10 bytes:

<?php
$inflatedOutput
= gzinflate(substr($output, 10, -8));
?>
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1
felix dot klee at inka dot de
1 year ago
The code below illustrates usage of the second parameter, in particular to protect against fatal out-of-memory errors. It outputs:

1000000
1000000
error

Tested with PHP 5.3 on 32bit Linux.

<?php

function tryToGzinflate($deflatedData, $maxLen = 0) {
 
$data = gzinflate($deflatedData, $maxLen);
  if (
$data === false)
    echo
'error<br>';
  else
    echo
strlen($data).'<br>';
}

// random data:
$data = '';
for (
$i = 0; $i < 1000000; $i++)
 
$data .= chr(mt_rand(97, 122)); // a-z

$deflatedData = gzdeflate($data);

ini_set('memory_limit', '5M'); // plenty of memory
tryToGzinflate($deflatedData);
tryToGzinflate($deflatedData, strlen($data));

ini_set('memory_limit', '100'); // little memory
tryToGzinflate($deflatedData, 100);
tryToGzinflate($deflatedData); // causes fatal out-of-memory error
?>
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1
niblett at gmail dot com
2 years ago
alternative, with detection for optional filename header
<?php
function gzdecode($data) {

       
// check if filename field is set in FLG, is 4th byte
       
$hex = bin2hex($data);

       
$flg = (int)hexdec(substr($hex, 6, 2));

       
// remove headers
       
$hex = substr($hex, 20);

       
$ret = '';
        if (  (
$flg & 0x8) == 8 ){
                print
"ello";
                for (
$i = 0; $i < strlen($hex); $i += 2 ){
                       
$value = substr($hex, $i, 2);
                        if (
$value == '00' ){
                               
$ret = substr($hex, ($i+2));
                                break;
                        }
                }
        }
        return
gzinflate(pack('H*', $ret));
}
?>
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1
John
6 years ago
And when retrieving mod_deflate gzip'ed content and using gzinflate() to decode the data, be sure to strip the first 11 chars from the retrieved content.

<?php $dec = gzinflate(substr($enc,11)); ?>
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0
patatraboum at free dot fr
7 years ago
Some gz string strip header and return inflated
It actualy processes some first member of the gz
See rfc1952 at http://www.faqs.org/rfcs/rfc1952.html for more details and improvment as gzdecode

<?php
function gzBody($gzData){
    if(
substr($gzData,0,3)=="\x1f\x8b\x08"){
       
$i=10;
       
$flg=ord(substr($gzData,3,1));
        if(
$flg>0){
            if(
$flg&4){
                list(
$xlen)=unpack('v',substr($gzData,$i,2));
               
$i=$i+2+$xlen;
            }
            if(
$flg&8) $i=strpos($gzData,"\0",$i)+1;
            if(
$flg&16) $i=strpos($gzData,"\0",$i)+1;
            if(
$flg&2) $i=$i+2;
        }
        return
gzinflate(substr($gzData,$i,-8));
    }
    else return
false;
}
?>
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0
spikeles_ at hotmail dot com
8 years ago
This can be used to inflate streams compressed by the Java class java.util.zip.Deflater but you must strip the first 2 bytes off it. ( much like the above comment )

<?php $result = gzinflate(substr($compressedData, 2)); ?>
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0
boris at gamate dot com
11 years ago
When retrieving mod_gzip'ed content and using gzinflate() to decode the data, be sure to strip the first 10 chars from the retrieved content.

<?php $dec = gzinflate(substr($enc,10)); ?>
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