Conversion Filters

Like the string.* filters, the convert.* filters perform actions similar to their names. The convert filters were added with PHP 5.0.0. For more information on a given filter, refer to the manual page for the corresponding function.

convert.base64-encode and convert.base64-decode Use of these filters are equivalent to processing all stream data through the base64_encode() and base64_decode() functions respectively. convert.base64-encode supports parameters given as an associative array. If line-length is given, the base64 output will be split into chunks of line-length characters each. If line-break-chars is given, each chunk will be delimited by the characters given. These parameters give the same effect as using base64_encode() with chunk_split().

Example #1 convert.base64-encode & convert.base64-decode

<?php
$fp 
fopen('php://output''w');
stream_filter_append($fp'convert.base64-encode');
fwrite($fp"This is a test.\n");
fclose($fp);
/* Outputs:  VGhpcyBpcyBhIHRlc3QuCg==  */

$param = array('line-length' => 8'line-break-chars' => "\r\n");
$fp fopen('php://output''w');
stream_filter_append($fp'convert.base64-encode'STREAM_FILTER_WRITE$param);
fwrite($fp"This is a test.\n");
fclose($fp);
/* Outputs:  VGhpcyBp
          :  cyBhIHRl
          :  c3QuCg==  */

$fp fopen('php://output''w');
stream_filter_append($fp'convert.base64-decode');
fwrite($fp"VGhpcyBpcyBhIHRlc3QuCg==");
fclose($fp);
/* Outputs:  This is a test.  */
?>

convert.quoted-printable-encode and convert.quoted-printable-decode Use of the decode version of this filter is equivalent to processing all stream data through the quoted_printable_decode() functions. There is no function equivalent to convert.quoted-printable-encode. convert.quoted-printable-encode supports parameters given as an associative array. In addition to the parameters supported by convert.base64-encode, convert.quoted-printable-encode also supports boolean arguments binary and force-encode-first. convert.base64-decode only supports the line-break-chars parameter as a type-hint for stripping from the encoded payload.

Example #2 convert.quoted-printable-encode & convert.quoted-printable-decode

<?php
$fp 
fopen('php://output''w');
stream_filter_append($fp'convert.quoted-printable-encode');
fwrite($fp"This is a test.\n");
/* Outputs:  =This is a test.=0A  */
?>
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marcus at synchromedia dot co dot uk
2 years ago
It's not quite obvious what all the available parameters are for convert.quoted-printable-encode. If you want the stream filter to act the same way as the quoted_printable_encode function, you need these extra params, for example:

stream_filter_append(
    STDOUT,
    'convert.quoted-printable-encode',
    STREAM_FILTER_WRITE,
    [
        'line-break-chars' => PHP_EOL,
        'line-length' => 75,
    ]
);
echo stream_copy_to_stream(STDIN, STDOUT);

Without these extra params set, you may get no wrapping at all, or wrapping using the wrong line break sequence.
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