What is the purpose of the buffer functions used in Slim PHP codebase?

Question

I am going the codebase of slim php for educational purposes, I kind of understand alot from reading it. however, i am finding it really difficult to understand the purpose of the buffer used in the 'main' run method of the App class.

public function run($silent = false)
{
    $response = $this->container->get('response');

    try {
        ob_start();
        $response = $this->process($this->container->get('request'), $response);
    } catch (InvalidMethodException $e) {
        $response = $this->processInvalidMethod($e->getRequest(), $response);
    } finally {
        $output = ob_get_clean();
    }

    if (!empty($output) && $response->getBody()->isWritable()) {
        $outputBuffering = $this->container->get('settings')['outputBuffering'];
        if ($outputBuffering === 'prepend') {
            // prepend output buffer content
            $body = new Http\Body(fopen('php://temp', 'r+'));
            $body->write($output . $response->getBody());
            $response = $response->withBody($body);
        } elseif ($outputBuffering === 'append') {
            // append output buffer content
            $response->getBody()->write($output);
        }
    }

    $response = $this->finalize($response);

    if (!$silent) {
        $this->respond($response);
    }

    return $response;
}

i have tried to dump the value of ob_get_clean() but it is always empty.

Possible duplicate of [What is output buffering?](https://stackoverflow.com/questions/2832010/what-is-output-buffering) — CecilMerrell aka bringrainfire, Oct 30 '18 at 14:52
`ob_get_clean()` will only return something when userland code prints output or emits an error message. I presume it's a mechanism to control such events. — Álvaro González, Oct 30 '18 at 14:53
@ÁlvaroGonzález thank you so much, makes perfert sense for me now — Ewomazino Ukah, Oct 30 '18 at 15:35

score 2 · Accepted Answer · answered Nov 06 '18 at 17:11

2

This is done in order to always return a PSR-7 Response. If you echo or print_r() inside your routes/middleware this will get prepended to the response body if the outputBuffering setting is set to prepend or if set to append it will be appended.

answered Nov 06 '18 at 17:11

VaaChar

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What is the purpose of the buffer functions used in Slim PHP codebase?

1 Answers1