Like the string.* filters, the convert.* filters perform actions similar to their names. For more information on a given filter, refer to the manual page for the corresponding function.
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. */
?>
Use of the decode version of this filter is equivalent to processing all stream
data through the quoted_printable_decode() function.
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 */
?>
The convert.iconv.* filters are available, if
iconv support is enabled, and their use is
equivalent to processing all stream data with iconv() .
These filters do not support parameters, but instead expect the input and
output encodings to be given as part of the filter name, i.e. either as
convert.iconv.<input-encoding>.<output-encoding> or
convert.iconv.<input-encoding>/<output-encoding>
(both notations are semantically equivalent).
Example #3 convert.iconv.*
<?php
$fp = fopen('php://output', 'w');
stream_filter_append($fp, 'convert.iconv.utf-16le.utf-8');
fwrite($fp, "T0円h0円i0円s0円 0円i0円s0円 0円a0円 0円t0円e0円s0円t0円.0円\n0円");
fclose($fp);
/* Outputs: This is a test. */
?>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.