<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @see http://github.com/zendframework/zend-diactoros for the canonical source repository
* @copyright Copyright (c) 2015-2016 Zend Technologies USA Inc. (http://www.zend.com)
* @license https://github.com/zendframework/zend-diactoros/blob/master/LICENSE.md New BSD License
*/
namespace Zend\Diactoros;
use Psr\Http\Message\StreamInterface;
use UnexpectedValueException;
use function array_pop;
use function implode;
use function ltrim;
use function preg_match;
use function sprintf;
use function str_replace;
use function ucwords;
/**
* Provides base functionality for request and response de/serialization
* strategies, including functionality for retrieving a line at a time from
* the message, splitting headers from the body, and serializing headers.
*/
abstract class AbstractSerializer
{
const CR = "\r";
const EOL = "\r\n";
const LF = "\n";
/**
* Retrieve a single line from the stream.
*
* Retrieves a line from the stream; a line is defined as a sequence of
* characters ending in a CRLF sequence.
*
* @param StreamInterface $stream
* @return string
* @throws UnexpectedValueException if the sequence contains a CR or LF in
* isolation, or ends in a CR.
*/
protected static function getLine(StreamInterface $stream)
{
$line = '';
$crFound = false;
while (! $stream->eof()) {
$char = $stream->read(1);
if ($crFound && $char === self::LF) {
$crFound = false;
break;
}
// CR NOT followed by LF
if ($crFound && $char !== self::LF) {
throw new UnexpectedValueException('Unexpected carriage return detected');
}
// LF in isolation
if (! $crFound && $char === self::LF) {
throw new UnexpectedValueException('Unexpected line feed detected');
}
// CR found; do not append
if ($char === self::CR) {
$crFound = true;
continue;
}
// Any other character: append
$line .= $char;
}
// CR found at end of stream
if ($crFound) {
throw new UnexpectedValueException("Unexpected end of headers");
}
return $line;
}
/**
* Split the stream into headers and body content.
*
* Returns an array containing two elements
*
* - The first is an array of headers
* - The second is a StreamInterface containing the body content
*
* @param StreamInterface $stream
* @return array
* @throws UnexpectedValueException For invalid headers.
*/
protected static function splitStream(StreamInterface $stream)
{
$headers = [];
$currentHeader = false;
while ($line = self::getLine($stream)) {
if (preg_match(';^(?P<name>[!#$%&\'*+.^_`\|~0-9a-zA-Z-]+):(?P<value>.*)$;', $line, $matches)) {
$currentHeader = $matches['name'];
if (! isset($headers[$currentHeader])) {
$headers[$currentHeader] = [];
}
$headers[$currentHeader][] = ltrim($matches['value']);
continue;
}
if (! $currentHeader) {
throw new UnexpectedValueException('Invalid header detected');
}
if (! preg_match('#^[ \t]#', $line)) {
throw new UnexpectedValueException('Invalid header continuation');
}
// Append continuation to last header value found
$value = array_pop($headers[$currentHeader]);
$headers[$currentHeader][] = $value . ltrim($line);
}
// use RelativeStream to avoid copying initial stream into memory
return [$headers, new RelativeStream($stream, $stream->tell())];
}
/**
* Serialize headers to string values.
*
* @param array $headers
* @return string
*/
protected static function serializeHeaders(array $headers)
{
$lines = [];
foreach ($headers as $header => $values) {
$normalized = self::filterHeader($header);
foreach ($values as $value) {
$lines[] = sprintf('%s: %s', $normalized, $value);
}
}
return implode("\r\n", $lines);
}
/**
* Filter a header name to wordcase
*
* @param string $header
* @return string
*/
protected static function filterHeader($header)
{
$filtered = str_replace('-', ' ', $header);
$filtered = ucwords($filtered);
return str_replace(' ', '-', $filtered);
}
}