# PSR-7 Message Implementation
This repository contains a full [PSR-7](https://www.php-fig.org/psr/psr-7/)
message implementation, several stream decorators, and so...
# PSR-7 Message Implementation
This repository contains a full [PSR-7](https://www.php-fig.org/psr/psr-7/)
message implementation, several stream decorators, and some helpful
functionality like query string parsing.
# Installation
```shell
composer require guzzlehttp/psr7
```
# Stream implementation
This package comes with a number of stream implementations and stream
decorators.
## AppendStream
`GuzzleHttpPsr7AppendStream`
Reads from multiple streams, one after the other.
```php
use GuzzleHttpPsr7;
$a = Psr7Utils::streamFor('abc, ');
$b = Psr7Utils::streamFor('123.');
$composed = new Psr7AppendStream([$a, $b]);
$composed->addStream(Psr7Utils::streamFor(' Above all listen to me'));
echo $composed; // abc, 123. Above all listen to me.
```
## BufferStream
`GuzzleHttpPsr7BufferStream`
Provides a buffer stream that can be written to fill a buffer, and read
from to remove bytes from the buffer.
This stream returns a "hwm" metadata value that tells upstream consumers
what the configured high water mark of the stream is, or the maximum
preferred size of the buffer.
```php
use GuzzleHttpPsr7;
// When more than 1024 bytes are in the buffer, it will begin returning
// false to writes. This is an indication that writers should slow down.
$buffer = new Psr7BufferStream(1024);
```
## CachingStream
The CachingStream is used to allow seeking over previously read bytes on
non-seekable streams. This can be useful when transferring a non-seekable
entity body fails due to needing to rewind the stream (for example, resulting
from a redirect). Data that is read from the remote stream will be buffered in
a PHP temp stream so that previously read bytes are cached first in memory,
then on disk.
```php
use GuzzleHttpPsr7;
$original = Psr7Utils::streamFor(fopen('http://www.google.com', 'r'));
$stream = new Psr7CachingStream($original);
$stream->read(1024);
echo $stream->tell();
// 1024
$stream->seek(0);
echo $stream->tell();
// 0
```
## DroppingStream
`GuzzleHttpPsr7DroppingStream`
Stream decorator that begins dropping data once the size of the underlying
stream becomes too full.
```php
use GuzzleHttpPsr7;
// Create an empty stream
$stream = Psr7Utils::streamFor();
// Start dropping data when the stream has more than 10 bytes
$dropping = new Psr7DroppingStream($stream, 10);
$dropping->write('01234567890123456789');
echo $stream; // 0123456789
```
## FnStream
`GuzzleHttpPsr7FnStream`
Compose stream implementations based on a hash of functions.
Allows for easy testing and extension of a provided stream without needing
to create a concrete class for a simple extension point.
```php
use GuzzleHttpPsr7;
$stream = Psr7Utils::streamFor('hi');
$fnStream = Psr7FnStream::decorate($stream, [
'rewind' => function () use ($stream) {
echo 'About to rewind - ';
$stream->rewind();
echo 'rewound!';
}
]);
$fnStream->rewind();
// Outputs: About to rewind - rewound!
```
## InflateStream
`GuzzleHttpPsr7InflateStream`
Uses PHP's zlib.inflate filter to inflate zlib (HTTP deflate, RFC1950) or gzipped (RFC1952) content.
This stream decorator converts the provided stream to a PHP stream resource,
then appends the zlib.inflate filter. The stream is then converted back
to a Guzzle stream resource to be used as a Guzzle stream.
## LazyOpenStream
`GuzzleHttpPsr7LazyOpenStream`
Lazily reads or writes to a file that is opened only after an IO operation
take place on the stream.
```php
use GuzzleHttpPsr7;
$stream = new Psr7LazyOpenStream('/path/to/file', 'r');
// The file has not yet been opened...
echo $stream->read(10);
// The file is opened and read from only when needed.
```
## LimitStream
`GuzzleHttpPsr7LimitStream`
LimitStream can be used to read a subset or slice of an existing stream object.
This can be useful for breaking a large file into smaller pieces to be sent in
chunks (e.g. Amazon S3's multipart upload API).
```php
use GuzzleHttpPsr7;
$original = Psr7Utils::streamFor(fopen('/tmp/test.txt', 'r+'));
echo $original->getSize();
// >>> 1048576
// Limit the size of the body to 1024 bytes and start reading from byte 2048
$stream = new Psr7LimitStream($original, 1024, 2048);
echo $stream->getSize();
// >>> 1024
echo $stream->tell();
// >>> 0
```
## MultipartStream
`GuzzleHttpPsr7MultipartStream`
Stream that when read returns bytes for a streaming multipart or
multipart/form-data stream.
## NoSeekStream
`GuzzleHttpPsr7NoSeekStream`
NoSeekStream wraps a stream and does not allow seeking.
```php
use GuzzleHttpPsr7;
$original = Psr7Utils::streamFor('foo');
$noSeek = new Psr7NoSeekStream($original);
echo $noSeek->read(3);
// foo
var_export($noSeek->isSeekable());
// false
$noSeek->seek(0);
var_export($noSeek->read(3));
// NULL
```
## PumpStream
`GuzzleHttpPsr7PumpStream`
Provides a read only stream that pumps data from a PHP callable.
When invoking the provided callable, the PumpStream will pass the amount of
data requested to read to the callable. The callable can choose to ignore
this value and return fewer or more bytes than requested. Any extra data
returned by the provided callable is buffered internally until drained using
the read() function of the PumpStream. The provided callable MUST return
false when there is no more data to read.
## Implementing stream decorators
Creating a stream decorator is very easy thanks to the
`GuzzleHttpPsr7StreamDecoratorTrait`. This trait provides methods that
implement `PsrHttpMessageStreamInterface` by proxying to an underlying
stream. Just `use` the `StreamDecoratorTrait` and implement your custom
methods.
For example, let's say we wanted to call a specific function each time the last
byte is read from a stream. This could be implemented by overriding the
`read()` method.
```php
use PsrHttpMessageStreamInterface;
use GuzzleHttpPsr7StreamDecoratorTrait;
class EofCallbackStream implements StreamInterface
{
use StreamDecoratorTrait;
private $callback;
private $stream;
public function __construct(StreamInterface $stream, callable $cb)
{
$this->stream = $stream;
$this->callback = $cb;
}
public function read($length)
{
$result = $this->stream->read($length);
// Invoke the callback when EOF is hit.
if ($this->eof()) {
call_user_func($this->callback);
}
return $result;
}
}
```
This decorator could be added to any existing stream and used like so:
```php
use GuzzleHttpPsr7;
$original = Psr7Utils::streamFor('foo');
$eofStream = new EofCallbackStream($original, function () {
echo 'EOF!';
});
$eofStream->read(2);
$eofStream->read(1);
// echoes "EOF!"
$eofStream->seek(0);
$eofStream->read(3);
// echoes "EOF!"
```
## PHP StreamWrapper
You can use the `GuzzleHttpPsr7StreamWrapper` class if you need to use a
PSR-7 stream as a PHP stream resource.
Use the `GuzzleHttpPsr7StreamWrapper::getResource()` method to create a PHP
stream from a PSR-7 stream.
```php
use GuzzleHttpPsr7StreamWrapper;
$stream = GuzzleHttpPsr7Utils::streamFor('hello!');
$resource = StreamWrapper::getResource($stream);
echo fread($resource, 6); // outputs hello!
```
# Static API
There are various static methods available under the `GuzzleHttpPsr7` namespace.
## `GuzzleHttpPsr7Message::toString`
`public static function toString(MessageInterface $message): string`
Returns the string representation of an HTTP message.
```php
$request = new GuzzleHttpPsr7Request('GET', 'http://example.com');
echo GuzzleHttpPsr7Message::toString($request);
```
## `GuzzleHttpPsr7Message::bodySummary`
`public static function bodySummary(MessageInterface $message, int $truncateAt = 120): string|null`
Get a short summary of the message body.
Will return `null` if th