PSR-7 Message Implementation

This repository contains a partial PSR-7 message implementation, several stream decorators, and some helpful functionality like query string parsing. Currently missing ServerRequestInterface and UploadedFileInterface; a pull request for these features is welcome.

Stream implementation

This package comes with a number of stream implementations and stream decorators.

AppendStream

RingCentral\Psr7\AppendStream

Reads from multiple streams, one after the other.

use RingCentral\Psr7;

$a = Psr7\stream_for('abc, ');
$b = Psr7\stream_for('123.');
$composed = new Psr7\AppendStream([$a, $b]);

$composed->addStream(Psr7\stream_for(' Above all listen to me').

echo $composed(); // abc, 123. Above all listen to me.

BufferStream

RingCentral\Psr7\BufferStream

Provides a buffer stream that can be written to 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.

use RingCentral\Psr7;

// 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 Psr7\BufferStream(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.

use RingCentral\Psr7;

$original = Psr7\stream_for(fopen('http://www.google.com', 'r'));
$stream = new Psr7\CachingStream($original);

$stream->read(1024);
echo $stream->tell();
// 1024

$stream->seek(0);
echo $stream->tell();
// 0

DroppingStream

RingCentral\Psr7\DroppingStream

Stream decorator that begins dropping data once the size of the underlying stream becomes too full.

use RingCentral\Psr7;

// Create an empty stream
$stream = Psr7\stream_for();

// Start dropping data when the stream has more than 10 bytes
$dropping = new Psr7\DroppingStream($stream, 10);

$stream->write('01234567890123456789');
echo $stream; // 0123456789

FnStream

RingCentral\Psr7\FnStream

Compose stream implementations based on a hash of functions.

Allows for easy testing and extension of a provided stream without needing to to create a concrete class for a simple extension point.

use RingCentral\Psr7;

$stream = Psr7\stream_for('hi');
$fnStream = Psr7\FnStream::decorate($stream, [
    'rewind' => function () use ($stream) {
        echo 'About to rewind - ';
        $stream->rewind();
        echo 'rewound!';
    }
]);

$fnStream->rewind();
// Outputs: About to rewind - rewound!

InflateStream

RingCentral\Psr7\InflateStream

Uses PHP's zlib.inflate filter to inflate deflate or gzipped content.

This stream decorator skips the first 10 bytes of the given stream to remove the gzip header, 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

RingCentral\Psr7\LazyOpenStream

Lazily reads or writes to a file that is opened only after an IO operation take place on the stream.

use RingCentral\Psr7;

$stream = new Psr7\LazyOpenStream('/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

RingCentral\Psr7\LimitStream

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).

use RingCentral\Psr7;

$original = Psr7\stream_for(fopen('/tmp/test.txt', 'r+'));
echo $original->getSize();
// >>> 1048576

// Limit the size of the body to 1024 bytes and start reading from byte 2048
$stream = new Psr7\LimitStream($original, 1024, 2048);
echo $stream->getSize();
// >>> 1024
echo $stream->tell();
// >>> 0

MultipartStream

RingCentral\Psr7\MultipartStream

Stream that when read returns bytes for a streaming multipart or multipart/form-data stream.

NoSeekStream

RingCentral\Psr7\NoSeekStream

NoSeekStream wraps a stream and does not allow seeking.

use RingCentral\Psr7;

$original = Psr7\stream_for('foo');
$noSeek = new Psr7\NoSeekStream($original);

echo $noSeek->read(3);
// foo
var_export($noSeek->isSeekable());
// false
$noSeek->seek(0);
var_export($noSeek->read(3));
// NULL

PumpStream

RingCentral\Psr7\PumpStream

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 RingCentral\Psr7\StreamDecoratorTrait. This trait provides methods that implement Psr\Http\Message\StreamInterface 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.

use Psr\Http\Message\StreamInterface;
use RingCentral\Psr7\StreamDecoratorTrait;

class EofCallbackStream implements StreamInterface
{
    use StreamDecoratorTrait;

    private $callback;

    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:

use RingCentral\Psr7;

$original = Psr7\stream_for('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 RingCentral\Psr7\StreamWrapper class if you need to use a PSR-7 stream as a PHP stream resource.

Use the RingCentral\Psr7\StreamWrapper::getResource() method to create a PHP stream from a PSR-7 stream.

use RingCentral\Psr7\StreamWrapper;

$stream = RingCentral\Psr7\stream_for('hello!');
$resource = StreamWrapper::getResource($stream);
echo fread($resource, 6); // outputs hello!

Function API

There are various functions available under the RingCentral\Psr7 namespace.

function str

function str(MessageInterface $message)

Returns the string representation of an HTTP message.

$request = new RingCentral\Psr7\Request('GET', 'http://example.com');
echo RingCentral\Psr7\str($request);

function uri_for

function uri_for($uri)

This function accepts a string or Psr\Http\Message\UriInterface and returns a UriInterface for the given value. If the value is already a UriInterface, it is returned as-is.

$uri = RingCentral\Psr7\uri_for('http://example.com');
assert($uri === RingCentral\Psr7\uri_for($uri));

function stream_for

function stream_for($resource = '', array $options = [])

Create a new stream based on the input type.

Options is an associative array that can contain the following keys:

• • metadata: Array of custom metadata.
• • size: Size of the stream.

This method accepts the following $resource types:

• Psr\Http\Message\StreamInterface: Returns the value as-is.
• string: Creates a stream object that uses the given string as the contents.
• resource: Creates a stream object that wraps the given PHP stream resource.
• Iterator: If the provided value implements Iterator, then a read-only stream object will be created that wraps the given iterable. Each time the stream is read from, data from the iterator will fill a buffer and will be continuously called until the buffer is equal to the requested read size. Subsequent read calls will first read from the buffer and then call next on the underlying iterator until it is exhausted.
• object with __toString(): If the object has the __toString() method, the object will be cast to a string and then a stream will be returned that uses the string value.
• NULL: When null is passed, an empty stream object is returned.
• callable When a callable is passed, a read-only stream object will be created that invokes the given callable. The callable is invoked with the number of suggested bytes to read. The callable can return any number of bytes, but MUST return false when there is no more data to return. The stream object that wraps the callable will invoke the callable until the number of requested bytes are available. Any additional bytes will be buffered and used in subsequent reads.

$stream = RingCentral\Psr7\stream_for('foo');
$stream = RingCentral\Psr7\stream_for(fopen('/path/to/file', 'r'));

$generator function ($bytes) {
    for ($i = 0; $i < $bytes; $i++) {
        yield ' ';
    }
}

$stream = RingCentral\Psr7\stream_for($generator(100));

function parse_header

function parse_header($header)

Parse an array of header values containing ";" separated data into an array of associative arrays representing the header key value pair data of the header. When a parameter does not contain a value, but just contains a key, this function will inject a key with a '' string value.

function normalize_header

function normalize_header($header)

Converts an array of header values that may contain comma separated headers into an array of headers with no comma separated values.

function modify_request

function modify_request(RequestInterface $request, array $changes)

Clone and modify a request with the given changes. This method is useful for reducing the number of clones needed to mutate a message.

The changes can be one of:

• method: (string) Changes the HTTP method.
• set_headers: (array) Sets the given headers.
• remove_headers: (array) Remove the given headers.
• body: (mixed) Sets the given body.
• uri: (UriInterface) Set the URI.
• query: (string) Set the query string value of the URI.
• version: (string) Set the protocol version.

function rewind_body

function rewind_body(MessageInterface $message)

Attempts to rewind a message body and throws an exception on failure. The body of the message will only be rewound if a call to tell() returns a value other than 0.

function try_fopen

function try_fopen($filename, $mode)

Safely opens a PHP stream resource using a filename.

When fopen fails, PHP normally raises a warning. This function adds an error handler that checks for errors and throws an exception instead.

function copy_to_string

function copy_to_string(StreamInterface $stream, $maxLen = -1)

Copy the contents of a stream into a string until the given number of bytes have been read.

function copy_to_stream

function copy_to_stream(StreamInterface $source, StreamInterface $dest, $maxLen = -1)

Copy the contents of a stream into another stream until the given number of bytes have been read.

function hash

function hash(StreamInterface $stream, $algo, $rawOutput = false)

Calculate a hash of a Stream. This method reads the entire stream to calculate a rolling hash (based on PHP's hash_init functions).

function readline

function readline(StreamInterface $stream, $maxLength = null)

Read a line from the stream up to the maximum allowed buffer length.

function parse_request

function parse_request($message)

Parses a request message string into a request object.

function parse_server_request

function parse_server_request($message, array $serverParams = array())

Parses a request message string into a server-side request object.

function parse_response

function parse_response($message)

Parses a response message string into a response object.

function parse_query

function parse_query($str, $urlEncoding = true)

Parse a query string into an associative array.

If multiple values are found for the same key, the value of that key value pair will become an array. This function does not parse nested PHP style arrays into an associative array (e.g., foo[a]=1&foo[b]=2 will be parsed into ['foo[a]' => '1', 'foo[b]' => '2']).

function build_query

function build_query(array $params, $encoding = PHP_QUERY_RFC3986)

Build a query string from an array of key value pairs.

This function can use the return value of parseQuery() to build a query string. This function does not modify the provided keys when an array is encountered (like http_build_query would).

function mimetype_from_filename

function mimetype_from_filename($filename)

Determines the mimetype of a file by looking at its extension.

function mimetype_from_extension

function mimetype_from_extension($extension)

Maps a file extensions to a mimetype.

Static URI methods

The RingCentral\Psr7\Uri class has several static methods to manipulate URIs.

RingCentral\Psr7\Uri::removeDotSegments

public static function removeDotSegments($path) -> UriInterface

Removes dot segments from a path and returns the new path.

See http://tools.ietf.org/html/rfc3986#section-5.2.4

RingCentral\Psr7\Uri::resolve

public static function resolve(UriInterface $base, $rel) -> UriInterface

Resolve a base URI with a relative URI and return a new URI.

See http://tools.ietf.org/html/rfc3986#section-5

RingCentral\Psr7\Uri::withQueryValue

public static function withQueryValue(UriInterface $uri, $key, $value) -> UriInterface

Create a new URI with a specific query string value.

Any existing query string values that exactly match the provided key are removed and replaced with the given key value pair.

Note: this function will convert "=" to "%3D" and "&" to "%26".

RingCentral\Psr7\Uri::withoutQueryValue

public static function withoutQueryValue(UriInterface $uri, $key, $value) -> UriInterface

Create a new URI with a specific query string value removed.

Any existing query string values that exactly match the provided key are removed.

Note: this function will convert "=" to "%3D" and "&" to "%26".

RingCentral\Psr7\Uri::fromParts

public static function fromParts(array $parts) -> UriInterface

Create a RingCentral\Psr7\Uri object from a hash of parse_url parts.

Not Implemented

A few aspects of PSR-7 are not implemented in this project. A pull request for any of these features is welcome:

• Psr\Http\Message\ServerRequestInterface
• Psr\Http\Message\UploadedFileInterface