<?php
declare(strict_types=1);
namespace Ancarda\Psr7\StringStream;
use Psr\Http\Message\StreamInterface;
use RuntimeException;
/**
* Minimal string based PSR-7 Stream, ideal for use in Functional Tests
*/
class StringStream implements StreamInterface
{
/** @var string|null */
private $data;
/** @var int */
private $pointer = 0;
/** @var int */
private $length;
/**
* @param string $data
*/
public function __construct(string $data)
{
$this->data = $data;
$this->length = strlen($data);
}
/**
* Reads all data from the stream into a string, from the beginning to end.
*
* This method MUST attempt to seek to the beginning of the stream before
* reading data and read the stream until the end is reached.
*
* Warning: This could attempt to load a large amount of data into memory.
*
* This method MUST NOT raise an exception in order to conform with PHP's
* string casting operations.
*
* @see http://php.net/manual/en/language.oop5.magic.php#object.tostring
* @return string
*/
public function __toString(): string
{
return $this->data === null ? '' : $this->data;
}
/**
* Closes the stream and any underlying resources.
*
* @return void
*/
public function close(): void
{
$this->data = null;
$this->pointer = 0;
$this->length = 0;
}
/**
* Separates any underlying resources from the stream.
*
* After the stream has been detached, the stream is in an unusable state.
*
* @return resource|null Underlying PHP stream, if any
*/
public function detach()
{
$this->data = null;
$this->pointer = 0;
$this->length = 0;
return null;
}
/**
* Get the size of the stream if known.
*
* @return int Returns the size in bytes if known, or null if unknown.
*/
public function getSize(): int
{
return $this->length;
}
/**
* Returns the current position of the file read/write pointer
*
* @return int Position of the file pointer
* @throws RuntimeException on error.
*/
public function tell(): int
{
if ($this->data === null) {
throw new StreamUnusableException(__FUNCTION__);
}
return $this->pointer;
}
/**
* Returns true if the stream is at the end of the stream.
*
* @return bool
*/
public function eof(): bool
{
return $this->pointer === $this->length;
}
/**
* Returns whether or not the stream is seekable.
*
* @return bool
*/
public function isSeekable(): bool
{
return $this->data !== null;
}
/**
* Seek to a position in the stream.
*
* @link http://www.php.net/manual/en/function.fseek.php
* @param int $offset Stream offset
* @param int $whence Specifies how the cursor position will be calculated
* based on the seek offset. Valid values are identical to the built-in
* PHP $whence values for `fseek()`. SEEK_SET: Set position equal to
* offset bytes SEEK_CUR: Set position to current location plus offset
* SEEK_END: Set position to end-of-stream plus offset.
* @throws RuntimeException on failure.
*/
public function seek($offset, $whence = SEEK_SET): void
{
if ($this->data === null) {
throw new StreamUnusableException(__FUNCTION__);
}
switch ($whence) {
case SEEK_SET:
$this->pointer = $offset;
return;
case SEEK_CUR:
$this->pointer = $this->pointer + $offset;
return;
case SEEK_END:
$this->pointer = $this->length + $offset;
return;
}
}
/**
* Seek to the beginning of the stream.
*
* If the stream is not seekable, this method will raise an exception;
* otherwise, it will perform a seek(0).
*
* @throws RuntimeException on failure.
* @link http://www.php.net/manual/en/function.fseek.php
* @see seek()
*/
public function rewind(): void
{
if ($this->data === null) {
throw new StreamUnusableException(__FUNCTION__);
}
$this->pointer = 0;
}
/**
* Returns whether or not the stream is writable.
*
* @return bool
*/
public function isWritable(): bool
{
return $this->data !== null;
}
/**
* Write data to the stream.
*
* @param string $string The string that is to be written.
* @return int Returns the number of bytes written to the stream.
* @throws RuntimeException on failure.
*/
public function write($string): int
{
if ($this->data === null) {
throw new StreamUnusableException(__FUNCTION__);
}
// If we're at the end of the data, we can just append.
if ($this->eof()) {
$this->length += strlen($string);
$this->data .= $string;
$this->pointer = $this->length;
return strlen($string);
}
// If we're purely overwriting, we can do that with substr.
// If we have more to write than we can fit, we'll just substr the start and then concatenate the rest.
$this->data =
substr($this->data, 0, $this->pointer) .
$string .
substr($this->data, $this->pointer + strlen($string));
// Since we can do both overwriting and appending here, we'll just recalculate:
$this->length = strlen($this->data);
$this->pointer = $this->length;
return strlen($string);
}
/**
* Returns whether or not the stream is readable.
*
* @return bool
*/
public function isReadable(): bool
{
return $this->data !== null;
}
/**
* Read data from the stream.
*
* @param int $length Read up to $length bytes from the object and return
* them. Fewer than $length bytes may be returned if underlying stream
* call returns fewer bytes.
* @return string Returns the data read from the stream, or an empty string
* if no bytes are available.
* @throws RuntimeException if an error occurs.
*/
public function read($length): string
{
if ($this->data === null) {
throw new StreamUnusableException(__FUNCTION__);
}
$slice = substr($this->data, $this->pointer, $length);
$this->pointer = $this->pointer + $length;
return $slice;
}
/**
* Returns the remaining contents in a string
*
* @return string
* @throws RuntimeException if unable to read or an error occurs while
* reading.
*/
public function getContents(): string
{
if ($this->data === null) {
throw new StreamUnusableException(__FUNCTION__);
}
return $this->read($this->length - $this->pointer);
}
/**
* Get stream metadata as an associative array or retrieve a specific key.
*
* The keys returned are identical to the keys returned from PHP's
* stream_get_meta_data() function.
*
* @link http://php.net/manual/en/function.stream-get-meta-data.php
* @param string $key Specific metadata to retrieve.
* @return array<mixed>|null Returns an associative array if no key is
* provided. Returns a specific key value if a key is provided and the
* value is found, or null if the key is not found.
*/
public function getMetadata($key = null): ?array
{
return null;
}
}