<?php
declare(strict_types=1);
namespace Psr\Http\Message;
/**
* Describes a data stream.
*
* Typically, an instance will wrap a PHP stream; this interface provides
* a wrapper around the most common operations, including serialization of
* the entire stream to a string.
*/
interface StreamInterface
{
/**
* 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();
/**
* Closes the stream and any underlying resources.
*
* @return void
*/
public function close();
/**
* 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();
/**
* Get the size of the stream if known.
*
* @return int|null Returns the size in bytes if known, or null if unknown.
*/
public function getSize();
/**
* Returns the current position of the file read/write pointer
*
* @return int Position of the file pointer
* @throws \RuntimeException on error.
*/
public function tell();
/**
* Returns true if the stream is at the end of the stream.
*
* @return bool
*/
public function eof();
/**
* Returns whether or not the stream is seekable.
*
* @return bool
*/
public function isSeekable();
/**
* 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(int $offset, int $whence = SEEK_SET);
/**
* 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).
*
* @see seek()
* @link http://www.php.net/manual/en/function.fseek.php
* @throws \RuntimeException on failure.
*/
public function rewind();
/**
* Returns whether or not the stream is writable.
*
* @return bool
*/
public function isWritable();
/**
* 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 $string);
/**
* Returns whether or not the stream is readable.
*
* @return bool
*/
public function isReadable();
/**
* 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(int $length);
/**
* Returns the remaining contents in a string
*
* @return string
* @throws \RuntimeException if unable to read or an error occurs while
* reading.
*/
public function getContents();
/**
* 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|null $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(?string $key = null);
}