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Tale Stream

What is Tale Stream?

This is a direct implementation of the PSR-7 Psr\Http\Message\StreamInterface and the PSR-17 Psr\Http\Message\StreamFactoryInterface. It doesn't add any extra methods, only a few utility stream factories and some useful iterators for streams.

It acts as a stable streaming library core for full-fledged streaming libraries like socket implementations or filesystem abstractions.

Installation

composer req talesoft/tale-stream

Usage

Check out the Functions File to see all things this library does.

Stream all the things

The heart is the Tale\Stream class you can use with the Tale\stream function. You can pass any resource of type stream and have a PSR-7 compatible stream for any purpose.

use function Tale\stream;

$stream = stream(fopen('/some/file', 'rb+'));

if ($stream->isReadable()) {
    $contents = $stream->read(100);
}

if ($stream->isWritable()) {
    $stream->write('Some Content');
}

$stream->close();

Create a Stream factory for DI containers

use Psr\Http\Message\StreamFactoryInterface;
use Tale\StreamFactory;

$container->add(StreamFactory::class);

// ...

$streamFactory = $container->get(StreamFactoryInterface::class);

$stream = $streamFactory->createStreamFromFile('./some-file.txt', 'rb');

echo $stream; // "<contents of some-file.txt>"

File Streams

The filestream works analogous to the fopen($filename, $mode, $useIncludePath, $context) function.

use function Tale\stream_file;

$stream = stream_file('./some-file.txt', 'rb');

echo $stream->getContents(); // "<contents of some-file.txt>"

Memory Streams

Memory streams only reside in memory and are gone when the execution ended. This is very useful to create streams on the fly wherever you need one. They are always readable and writable.

use function Tale\stream_memory;

$stream = stream_memory('Some Content!');

echo $stream->getContents(); // "Some Content!"

Temporary Streams

Temporary streams work like memory streams, but at some point they will start swapping data into a file to save memory.

use function Tale\stream_memory;

$stream = stream_temp('Some Content!', 1024);
// Stream will start swapping after 1024 bytes

Input Stream

The input stream is a readable file stream on php://input. In most cases, this is the raw HTTP request body and useful for APIs that work with structured data formats.

use function Tale\stream_input;

$stream = stream_input();

$data = json_decode($stream->getContents());
echo $data['firstName'];

Output Stream

The output stream is a writable file stream on php://output. This is mostly the output content that is sent to the browser.

use function Tale\stream_output;

$stream = stream_output();

$stream->write('<h1>This will be sent to the browser</h1>');

STDIN Stream

The standard input stream is a readable file stream on php://stdin. This is e.g. content from a piped command.

use function Tale\stream_stdin;

$stream = stream_stdin();

echo $stream->getContents(); // "<piped input>"

STDERR Stream

The standard error stream is a writable file stream on php://stderr. This is mostly used for output of errors in console commands.

use function Tale\stream_stderr;

$stream = stream_stderr();

$stream->write('Error: Something bad happened');

STDOUT Stream

The standard output stream is a writable file stream on php://stdout. This is mostly console command output.

use function Tale\stream_stdout;

$stream = stream_stdout();

$stream->write("Working...please wait...\n");

Null Stream

The null-stream does nothing. It only implements the interfaces. Useful to avoid defensive null checks on optional dependencies, to suppress things and for testing.

use function Tale\stream_null;

$stream = stream_null();

echo $stream->read(100); // Will always return an empty string

Read streams with iterators

The ReadIterator will read a stream chunk-by-chunk (default chunk size is 1024). Notice, all the iterators here work with any PSR-7 stream, not only Tale\Stream instances.

use function Tale\stream_memory;
use function Tale\stream_read;

$stream = stream_memory('abcdefg');

$iterator = stream_read($stream, 2); //Chunk size of 2

$chunks = iterator_to_array($iterator);
// You could alternatively iterate the iterator with foreach

dump($chunks); // ['ab', 'cd', 'ef', 'g']

Iterate lines of a stream

The LineIterator works differently to fgets(). While the chunk size on fgets() limits the length a line can has, the LineIterator will just wait for the actual end of the line and doesn't care about the chunk size.

use function Tale\stream_memory;
use function Tale\stream_get_lines;

$stream = stream_memory("Line 1\nLine 2\nLine 3");

$lines = stream_get_lines($stream);

dump(iterator_to_array($lines)); // ["Line 1", "Line 2", "Line 3"]

Split streams by delimiters

The SplitIterator is the reason why the LineIterator can work like it does. It can split streams by any delimiter of any length and doesn't care about the chunk size of the internal reader.

use function Tale\stream_memory;
use function Tale\stream_split;

$stream = stream_memory('a,b,c,d');

$items = stream_split($stream, ',');

dump(iterator_to_array($items)); // ['a', 'b', 'c', 'd']

Write to streams with iterators

The WriteIterator is a utility to write iterables to streams easily.

use function Tale\stream_memory;
use function Tale\stream_write;

function generateLines()
{
    yield "Line 1\n";
    yield "Line 2\n";
    yield "Line 3\n";
}

$stream = stream_memory();

$writer = stream_write($stream, generateLines());
$writtenBytes = $writer->writeAll();

// or use stream_write_all()
$writtenBytes = stream_write_all($stream, generateLines());

// You could also iterate the write to leave place for other actions
// e.g. in async environments

Pipe streams

The ReadIterator and WriteIterator combined provide a solid way to pipe streams efficiently.

use function Tale\stream_memory;
use function Tale\stream_pipe;

$inputStream = stream_memory('Some content');
$outputStream = stream_memory();

$writer = stream_pipe($inputStream, $outputStream);
$writer->writeAll();

// or use stream_pipe_all()
$writtenBytes = stream_pipe_all($inputStream, $outputStream);

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