PHP Australia Conference 2015

base64_encode

(PHP 4, PHP 5)

base64_encodeCodifica dados com MIME base64

Descrição

string base64_encode ( string $data )

Codifica a dada data com base64.

Esta codificação é designada para que dados binários durem no transporte sobre camadas de transorte que não são 8-bit clean, como mensagens de e-mail.

Dados codificados na Base-64 tem aproximadamente 33% mais espaço que dos dados originais.

Parâmetros

data

A informação a ser codificada.

Valor Retornado

A informação codificada, como uma string.

Exemplos

Exemplo #1 Exemplo base64_encode()

<?php
  $str 
'This is an encoded string';
  echo 
base64_encode($str);
?>

O exemplo acima irá imprimir:

VGhpcyBpcyBhbiBlbmNvZGVkIHN0cmluZw==

Veja Também

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User Contributed Notes 31 notes

up
25
gutzmer at usa dot net
3 years ago
For anyone interested in the 'base64url' variant encoding, you can use this pair of functions:

<?php
function base64url_encode($data) {
  return
rtrim(strtr(base64_encode($data), '+/', '-_'), '=');
}

function
base64url_decode($data) {
  return
base64_decode(str_pad(strtr($data, '-_', '+/'), strlen($data) % 4, '=', STR_PAD_RIGHT));
}
?>
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12
MitMacher
5 years ago
Unfortunately my "function" for encoding base64 on-the-fly from 2007 [which has been removed from the manual in favor of this post] had 2 errors!
The first led to an endless loop because of a missing "$feof"-check, the second caused the rare mentioned errors when encoding failed for some reason in larger files, especially when
setting fgets($fh, 2) for example. But lower values then 1024 are bad overall because they slow down the whole process, so 4096 will be fine for all purposes, I guess.
The error was caused by the use of "empty()".

Here comes the corrected version which I have tested for all kind of files and length (up to 4,5 Gb!) without any error:

<?php
$fh
= fopen('Input-File', 'rb');
//$fh2 = fopen('Output-File', 'wb');

$cache = '';
$eof = false;

while (
1) {

    if (!
$eof) {
        if (!
feof($fh)) {
           
$row = fgets($fh, 4096);
        } else {
           
$row = '';
           
$eof = true;
        }
    }

    if (
$cache !== '')
       
$row = $cache.$row;
    elseif (
$eof)
        break;

   
$b64 = base64_encode($row);
   
$put = '';

    if (
strlen($b64) < 76) {
        if (
$eof) {
           
$put = $b64."\n";
           
$cache = '';
        } else {
           
$cache = $row;
        }

    } elseif (
strlen($b64) > 76) {
        do {
           
$put .= substr($b64, 0, 76)."\n";
           
$b64 = substr($b64, 76);
        } while (
strlen($b64) > 76);

       
$cache = base64_decode($b64);

    } else {
        if (!
$eof && $b64{75} == '=') {
           
$cache = $row;
        } else {
           
$put = $b64."\n";
           
$cache = '';
        }
    }

    if (
$put !== '') {
        echo
$put;
       
//fputs($fh2, $put);
        //fputs($fh2, base64_decode($put));        // for comparing
   
}
}

//fclose($fh2);
fclose($fh);
?>
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10
luke at lukeoliff.com
3 years ago
A function I'm using to return local images as base64 encrypted code, i.e. embedding the image source into the html request.

This will greatly reduce your page load time as the browser will only need to send one server request for the entire page, rather than multiple requests for the HTML and the images. Requests need to be uploaded and 99% of the world are limited on their upload speed to the server.

<?php
function base64_encode_image ($filename=string,$filetype=string) {
    if (
$filename) {
       
$imgbinary = fread(fopen($filename, "r"), filesize($filename));
        return
'data:image/' . $filetype . ';base64,' . base64_encode($imgbinary);
    }
}
?>

used as so

<style type="text/css">
.logo {
    background: url("<?php echo base64_encode_image ('img/logo.png','png'); ?>") no-repeat right 5px;
}
</style>

or

<img src="<?php echo base64_encode_image ('img/logo.png','png'); ?>"/>
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4
Cristiano Calligaro
9 years ago
I've used base64_encode and base64_decode for file attachment both in MySQL (using a BLOB field) and MSSQL (using a TEXT field). For MSSQL remember to set in PHP.INI file both mssql.textsize and mssql.textlimit to 2147483647.

Here's the code:

######### MSSQL(mssql_)/MySQL(mysql_) file attach
$val=$HTTP_POST_FILES['lob_upload']['tmp_name'];
$valn=$HTTP_POST_FILES['lob_upload']['name'];
$valt=$HTTP_POST_FILES['lob_upload']['type'];

$data=base64_encode(addslashes(fread(fopen($val, "r"), filesize($val))));

mssql_connect("srv","usr","pass") or die ("");
mssql_select_db("db") or die ("");
$query = "UPDATE $table SET $field='$data', $fieldname='$valn', $fieldtype='$valt' WHERE DocID='$DocID'";
$result = mssql_query($query) or die(mssql_error());
mssql_close();

######### MSSQL(mssql_)/MySQL(mysql_) open file attached
mssql_connect("srv","usr","pass") or die ("");
mssql_select_db("db") or die ("");
$query = "SELECT $field,$fieldtype FROM $table WHERE DocID='$DocID'";
$result = mssql_query($query) or die(mssql_error());
$row = mssql_fetch_array($result);

header("Content-type: $row[1]");
echo stripslashes(base64_decode($row[0]));

This strategy is good for Microsoft Word, Acrobat PDF, JPG image and so on (even zipped files!!!)
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1
massimo dot scamarcia at gmail dot com
8 years ago
function urlsafe_b64encode($string) {
    $data = base64_encode($string);
    $data = str_replace(array('+','/','='),array('-','_',''),$data);
    return $data;
}

function urlsafe_b64decode($string) {
    $data = str_replace(array('-','_'),array('+','/'),$string);
    $mod4 = strlen($data) % 4;
    if ($mod4) {
        $data .= substr('====', $mod4);
    }
    return base64_decode($data);
}

Php version of perl's MIME::Base64::URLSafe, that provides an url-safe base64 string encoding/decoding (compatible with python base64's urlsafe methods)
up
0
Naser Mirzaei
3 months ago
<?php
$image
= 'example.png';

// Read image path, convert to base64 encoding
$imageData = base64_encode(file_get_contents($image));

// Format the image SRC:  data:{mime};base64,{data};
$src = 'data: '.mime_content_type($image).';base64,'.$imageData;

// Echo out a sample image
echo "<img src=\"$src\" alt=\"\" />";
?>
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-1
Hayley Watson
1 year ago
Base64 encoding of large files.

Base64 encoding converts triples of eight-bit symbols into quadruples of six-bit symbols. Reading the input file in chunks that are a multiple of three bytes in length results in a chunk that can be encoded independently of the rest of the input file. MIME additionally enforces a line length of 76 characters plus the CRLF. 76 characters is enough for 19 quadruples of six-bit symbols thus representing 19 triples of eight-bit symbols. Reading 57 eight-bit symbols provides exactly enough data for a complete MIME-formatted line. Finally, PHP's default buffer size is 8192 bytes - enough for 143 MIME lines' worth of input.

So if you read from the input file in chunks of 8151 (=57*143) bytes you will get (up to) 8151 eight-bit symbols, which encode as exactly 10868 six-bit symbols, which then wrap to exactly 143 MIME-formatted lines. There is no need to retain left-over symbols (either six- or eight-bit) from one chunk to the next. Just read a chunk, encode it, write it out, and go on to the next chunk. Obviously the last chunk will probably be shorter, but encoding it is still independent of the rest.

<?php

while(!feof($input_file))
{
   
$plain = fread($input_file, 57 * 143);
   
$encoded = base64_encode($plain);
   
$encoded = chunk_split($encoded, 76, "\r\n");
   
fwrite($output_file, $encoded);
}

?>

Conversely, each 76-character MIME-formatted line (not counting the trailing CRLF) contains exactly enough data for 57 bytes of output without needing to retain leftover bits that need prepending to the next line. What that means is that each line can be decoded independently of the others, and the decoded chunks can then be concatenated together or written out sequentially. However, this does make the assumption that the encoded data really is MIME-formatted; without that assurance it is necessary to accept that the base64 data won't be so conveniently arranged.
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-1
Andi
6 years ago
I needed a simple way to obfuscate auto_increment primary keys in databases when they are visible to users in URIs or API calls. The users should not be able to increment the id in the URL and see the next data record in the database table.

My solution (uses modified base64 functions by Tom):

function base64url_encode($plainText) {
   
    $base64 = base64_encode($plainText);
    $base64url = strtr($base64, '+/=', '-_,');
    return $base64url;  
}

function base64url_decode($plainText) {
   
    $base64url = strtr($plainText, '-_,', '+/=');
    $base64 = base64_decode($base64url);
    return $base64;  
}

function encryptId($int, $class='') {
   
    return base64url_encode($int.'-'.substr(sha1($class.$int.encryptionKey), 0, 6));
}

function decryptId($string, $class='') {
   
    $parts = explode('-', base64url_decode($string));
    if (count($parts) != 2) {
       
        return 0;
    }
   
    $int = $parts[0];
    return substr(sha1($class.$int.encryptionKey), 0, 6) === $parts[1]
        ? (int)$int
        : 0;
}

- The optional 2nd argument is the class name, so two equal ids of different tables will not result in two equal obfuscated ids.

- encryptionKey is a global secret key for encryption.

- decryptId() checks if the second part of the base64 encoded string is correct.
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-1
dawgeatschikin at hotmail dot com
8 years ago
Just a minor tweak of massimo's functions.

<?
$data = str_replace(array('+','/','='),array('-','_','.'),$data);
//replace '=' with '.' instead of with nothing, that way the process is reversible.  '.' is uri-safe according to http://www.w3.org/Addressing/URL/5_URI_BNF.html
?>
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-1
Gabriel Malca
8 years ago
If the function doesn't exist, this is a messy but effective way of doing it:

<?

echo bencode("Gabriel Malca");
// R2FicmllbCBNYWxjYQ==

function bencode($string='') {
    $binval = convert_binary_str($string);
    $final = "";
    $start = 0;
    while ($start < strlen($binval)) {
        if (strlen(substr($binval,$start)) < 6)
            $binval .= str_repeat("0",6-strlen(substr($binval,$start)));
        $tmp = bindec(substr($binval,$start,6));
        if ($tmp < 26)
            $final .= chr($tmp+65);
        elseif ($tmp > 25 && $tmp < 52)
            $final .= chr($tmp+71);
        elseif ($tmp == 62)
            $final .= "+";
        elseif ($tmp == 63)
            $final .= "/";
        elseif (!$tmp)
            $final .= "A";
        else
            $final .= chr($tmp-4);
        $start += 6;
    }
    if (strlen($final)%4>0)
        $final .= str_repeat("=",4-strlen($final)%4);
    return $final;
}

function convert_binary_str($string) {
    if (strlen($string)<=0) return;
    $tmp = decbin(ord($string[0]));
    $tmp = str_repeat("0",8-strlen($tmp)).$tmp;
    return $tmp.convert_binary_str(substr($string,1));
}

?>
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-3
markrose at markrose dot ca
3 years ago
An even faster way to line-breaks every 64th character is using the chunk_split function:

<?php
$string
= chunk_split(base64_encode($string), 64, "\n");
?>
up
-4
andronick(dot)mail(dog)gmail(dot)com
4 years ago
output images into html:

<?php

$imgfile
= "test.gif";

$handle = fopen($filename, "r");

$imgbinary = fread(fopen($imgfile, "r"), filesize($imgfile));

echo
'<img src="data:image/gif;base64,' . base64_encode($imgbinary) . '" />';

?>

gif - data:image/gif;base64,...
jpg - data:image/jpeg;base64,...
png - data:image/png;base64,...
etc.
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-1
Tom
7 years ago
This function supports "base64url" as described in Section 5 of RFC 4648, "Base 64 Encoding with URL and Filename Safe Alphabet"

    <?php
   
function base64url_encode($plainText)
    {
       
$base64 = base64_encode($plainText);
       
$base64url = strtr($base64, '+/', '-_');
        return (
$base64url);   
    }
   
?>

You may wish to rtrim (or escape) trailing ='s for use in a URI.
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-2
juha at kuhazor dot idlegames dot com
10 years ago
If you use base64encoded strings as cookie names, make sure you remove '=' characters. At least Internet Explorer refuses cookie names containing '=' characters or urlencoded cookie names containing %xx character replacements. Use the function below to turn base64 encoded strings to bare alphabets (get rid of / and + characters as well)

<?php
function base64clean($base64string)
{
    
$base64string = str_replace(array('=','+','/'),'',$base64string);

     return
$base64string;
}
?>
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-3
pablo at compuar dot com
5 years ago
If you want to send a very long value over URL, you might consider using base64_encode, and discover that IE6 only supports 2000 or so chars.

So, Using a little bit of magic you can do this and be happy:

<?php
$string
= 'Blah';

$encoded = strtr(base64_encode(addslashes(gzcompress(serialize($string),9))), '+/=', '-_,');

$string= unserialize(gzuncompress(stripslashes(base64_decode(strtr($encoded, '-_,', '+/=')))));

?>
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-3
gglockner AT NOSPAMdwaffler DOT com
6 years ago
I have another solution that is simple and elegant.  Create a pseudorandom string of characters.  Then, each time you want to obfuscate your key, append a random substring from the pseudorandom string and use base64 encoding.  When you want to de-obfuscate, convert back from base64.  If the prefix is not in your pseudorandom source, then the value is forged.  Otherwise, strip the prefix and recover your original key.

The advantages are that the string will look different even for the same key, and encoding and decoding should be extremely fast.

Here's an example:

<?php

// Call makeCksum once upon landing on the homepage
function makeCksum() {
      
$str = "";
       for (
$i=0;$i<32;++$i)
              
$str .= chr(rand(32,126));
      
$_SESSION['Cksum'] = $str;
}

function
encode($x) {
    return
base64_encode(substr($_SESSION['Cksum'],rand(0,28),4) . $x);
}

function
decode($x) {
   
$y = base64_decode($x);
    if (
strpos($_SESSION['Cksum'],substr($y,0,4)) === false) return false;
    return
substr($y,4-strlen($y));
}
?>
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-2
eric [at] d512 [dot] com
7 years ago
Note that at least some Windows systems will not print a line of characters longer than a certain length unless it has line breaks of some kind.  So if you base-64 encode a file, print it back for debugging purposes, and see nothing, don't be alarmed.
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-2
dlyaza aT yahoo DOT com
7 years ago
Using Function:
Output for HTML Put:
<img src="$self?image=file" border="0" alt="file">
<img src="$self?image=folder" border="0" alt="folder">

function getimage ($image) {
    switch ($image) {
    case 'file':
        return base64_decode('R0lGODlhEQANAJEDAJmZmf///wAAAP///yH5BAHoAwMALAAAA
AARAA0AAAItnIGJxg0B42rsiSvCA/REmXQWhmnih3LUSGaqg35vF
bSXucbSabunjnMohq8CADsA');
    case 'folder':
        return base64_decode('R0lGODlhEQANAJEDAJmZmf///8zMzP///yH5BAHoAwMALAAAAA
ARAA0AAAIqnI+ZwKwbYgTPtIudlbwLOgCBQJYmCYrn+m3smY5v
Gc+0a7dhjh7ZbygAADsA');
    case 'hidden_file':
        return base64_decode('R0lGODlhEQANAJEDAMwAAP///5mZmf///yH5BAHoAwMALAAAA
AARAA0AAAItnIGJxg0B42rsiSvCA/REmXQWhmnih3LUSGaqg35vF
bSXucbSabunjnMohq8CADsA');
    case 'link':
        return base64_decode('R0lGODlhEQANAKIEAJmZmf///wAAAMwAAP///wAAAAAAAAAAA
CH5BAHoAwQALAAAAAARAA0AAAM5SArcrDCCQOuLcIotwgTYUll
NOA0DxXkmhY4shM5zsMUKTY8gNgUvW6cnAaZgxMyIM2zBLCaHlJgAADsA');
    case 'smiley':
        return base64_decode('R0lGODlhEQANAJECAAAAAP//AP///wAAACH5BAHoAwIALAAAA
AARAA0AAAIslI+pAu2wDAiz0jWD3hqmBzZf1VCleJQch0rkdnppB3
dKZuIygrMRE/oJDwUAOwA=');
    case 'arrow':
        return base64_decode('R0lGODlhEQANAIABAAAAAP///yH5BAEKAAEALAAAAAARAA0AA
AIdjA9wy6gNQ4pwUmav0yvn+hhJiI3mCJ6otrIkxxQAOw==');
    }
}
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php at ianco dot co dot uk
8 years ago
I am finding a length restriction with base64_encode (or possibly with echo) in PHP 4.3.9.
This works ok for me:
<?php
echo strlen(str_repeat('-', 3273)); // 3273
echo strlen(base64_encode(str_repeat('-', 3273))); // 4364
echo base64_encode(str_repeat('-', 3273)); // LS0t repeated
?>
But change the length to 3274 and the third echo prints nothing.
<?php
echo strlen(str_repeat('-', 3274)); // 3274
echo strlen(base64_encode(str_repeat('-', 3274))); // 4368
echo base64_encode(str_repeat('-', 3274)); // Nothing at all printed
?>
This has obvious implications if you're wanting to encode a fairly large serialized array and echo it to a form field.
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peter at mailinator dot com
8 years ago
If you want to decode base64 encoded data in Javascript, you can use the tool (Webtoolkit.base64) on this website: http://www.webtoolkit.info/
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-2
greenthumb at 4point-webdesign dot de
8 years ago
I had massive problems storing a serialized Object which contained UTF-8 parts and some ascii parts (from the serialization i think) into mysql.

So i used base64_encode to get a clean string which could be safely decoded and unserialized.

this is bulletproof - if you ever have trouble use this.
the runtime is imho no problem.
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-2
virtuall at virtuall dot info
8 years ago
If you encode text that contains symbols like < > and want to send it in GET query, be sure to urlencode the result of base64_encode, as it sometimes adds a  + (and it's a special symbol) at the end:

<?php
   
echo base64_encode('<html>');
?>

returns:

PGh0bWw+

A function like this could also be useful:

<?php
   
function base64_urlencode($str) {
        return
urlencode(base64_encode($str));
    };
?>
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gglockner AT NOSPAMdwaffler DOT com
6 years ago
I omitted the strtr functions in my examples.  Here are corrected functions:

<?php
function encode($x) {
    return
strtr(base64_encode(substr($_SESSION['Cksum'],rand(0,28),4) . $x), '+/=', '-_~');
}

function
decode($x) {
   
$y = base64_decode(strtr($x, '-_~', '+/='));
    if (
strpos($_SESSION['Cksum'],substr($y,0,4)) === false) return false;
    return
substr($y,4-strlen($y));
}
?>
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-3
Anonymous
6 years ago
a note on URI -safe base64.
Simply replacing + = and / with _ - and . doesn't work as the base64_encode function will insert \r \n chars as well which are not URI-safe. So unless we have a base64encode function that does not insert any newline and padddings, the output can never be URI -safe.

referring to the note posted by " web at pkasperski dot com"

- you might as well use $encoded = strtr ( base64_encode ($data), 'ABCDEFG.....', 'aBcDEfG....' ).

this is more efficient. Also, Is simply changing the casing of the letters  more secure? Why don't you try swapping letters around instead

- for your utf8_encode function, the "ord" function returns  a number in the range 0-255. Remember that strings in PHP are actually a sequence of bytes rather than chars. So your utf8 encode func may not work properly. and the line "for ($n = 0; $n < strlen($input); $n++) {" is inefficient, you should assign  a variable $count to  strlen($input) and use it.

referring to
"dlyaza aT yahoo DOT com"

whats the usefulness of encoding your images in a php file??

referring to  "php at ianco dot co dot uk"

- what version of php are you using? Your code works fine for me. I see all the output.
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massimo dot scamarcia at gmail dot com
8 years ago
$data = str_replace(array('+','/','='),array('-','_',),$data); // MIME::Base64::URLSafe implementation
      
$data = str_replace(array('+','/'),array('-','_'),$data); // Python raise "TypeError: Incorrect padding" if you remove "=" chars when decoding
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conradopinto at yahoo dot com dot br
8 years ago
There is an error on the example of passing an array through an HTML Form.

In the line:
$array = unserialize(base64_decode($coded_array);

There is a ')' missing. it should be:
$array = unserialize(base64_decode($coded_array));
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-3
guy at bhaktiandvedanta dot com
11 years ago
You can use base64_encode to transfer image file into string text and then display them. I used this to store my images in a database and display them form there. First I open the files using fread, encoded the result, and stored that result in the database. Useful for creating random images.

image.php:

<?

header(" Content-Type: image/jpeg");
header(" Content-Disposition: inline");
$sql = "SELECT data FROM image where name='".$img."'";
$result = mysql_query($sql);
$row = mysql_fetch_row($result);
$image = $row[0];
echo base64_decode($image);

?>

And in the html file you put:

<img src="image.php?img=test3"  border="0" alt="">

Guy Laor
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nishantmathur62 at gmail dot com
11 months ago
<?php
$file
="test.jpg";
$file_cont=file_get_contents($file);
$image=base64_encode($file_cont);
$src = 'data:;base64,'.$image;

if(
copy($src,'test2.jpg'))
  {
      echo
"success";
  }
  else
  {
      echo
"Error";
  }
?>
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-5
Gerard
1 year ago
To make base64_encode encode a URL safe string compatible with .net HttpServerUtility.UrlTokenEncode function use this:

<?php
url_safe_base64_encode
($string)
  {
   
#First base64 encode
   
$data = base64_encode($string);

   
#Base64 strings can end in several = chars. These need to be translated into a number
   
$no_of_eq = substr_count($data, "=");
   
$data = str_replace("=", "", $data);
   
$data = $data.$no_of_eq;

   
#Then replace all non-url safe characters
   
$data = str_replace(array('+','/'),array('-','_'),$data);
    return
$data;
  }
?>
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mightymrj at hotmail dot com
9 years ago
Problem: mime attachments sending as blank or almost completely blank documents (all data is lost)

Explanation: After a couple days of trying to mime pdf attachments without losing all data, I finally came across this function in some obsolete obscure post:

set_magic_quotes_runtime()

This is set to on by default in the machine, and it causes fread() and/or base64_encode() (both used in most mime examples I've seen) to read or encrypt binary without slashes for special characters.  This causes sent files to process incorrectly, breaking, thus truncating most of the data in the file. 

Fix: pass 0 to this function and it will do a one time turn off while your code executes.

example:
<?php
   set_magic_quotes_runtime
(0);
?>

This can also been turned off in the php.ini file, but I'm not sure what uses that setting or what the consequences might be.

info:
   http://us2.php.net/manual/en/function.set-magic-quotes-runtime.php
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jonb at wobblymusic dot com
5 years ago
Note that some applications, such as OpenSSL's enc command, require that there be a line break every 64 characters in order for their base64 decode function to work. The following function will take care of this problem:

<?php
function ($encodeMe) {
   
$data = base64_encode($encodeMe);
   
$datalb = "";
    while (
strlen($data) > 64) {
       
$datalb .= substr($data, 0, 64) . "\n";
       
$data = substr($data,64);
    }
   
$datalb .= $data;
    return
$datalb;
}
?>
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