Emitting Responses

Introduction

Deprecated

Emitters are deprecated from Diactoros starting with version 1.8.0. The functionality is now available for any PSR-7 implementation via the package laminas/laminas-httphandlerrunner. We suggest using that functionality instead.

If you are using a non-SAPI PHP implementation and wish to use the Server class, or if you do not want to use the Server implementation but want to emit a response, this package provides an interface, Laminas\Diactoros\Response\EmitterInterface, defining a method emit() for emitting the response.

Diactoros provides two implementations currently, both for working with traditional Server API (SAPI) implementations: Laminas\Diactoros\Response\SapiEmitter and Laminas\Diactoros\Response\SapiStreamEmitter. Each uses the native header() PHP function to emit headers, and echo() to emit the response body.

If you are using a non-SAPI implementation, you will need to create your own EmitterInterface implementation.

For example, the SapiEmitter implementation of the EmitterInterface can be used thus:

$response = new Laminas\Diactoros\Response();
$response->getBody()->write("some content\n");
$emitter = new Laminas\Diactoros\Response\SapiEmitter();
$emitter->emit($response);

Emitting Ranges of streamed Files

The SapiStreamEmitter is useful when you want to emit a Content-Range. As an example, to stream a range of bytes from a file to a client, the client can pass the following header:

Range: bytes=1024-2047

Your application would then populate the response with a Content-Range header:

$range = $request->getHeaderLine('range');
$range = str_replace('=', ' ', $range);

$body = new Stream($pathToFile);
$size = $body->getSize();
$range .= '/' . $size;

$response = new Response($body);
$response = $response->withHeader('Content-Range', $range);

(Note: you will likely want to ensure the range specified falls within the content size of the streamed body!)

The SapiStreamEmitter detects the Content-Range header and emits only the bytes specified.

$emitter = new SapiStreamEmitter();
$emitter->emit($response);

The SapiStreamEmitter may be used in place of the SapiEmitter, even when not sending files. However, unlike the SapiEmitter, it will emit a chunk of content at a time instead of the full content at once, which could lead to performance overhead. The default chunk size is 8192 bytes.