使用 POST 表单上传文件

<!-- make sure the attribute enctype is set to multipart/form-data -->
<form method="post" enctype="multipart/form-data">
    <!-- upload of a single file -->
    <p>
        <label>Add file (single): </label><br/>
        <input type="file" name="example1"/>
    </p>

    <!-- multiple input fields for the same input name, use brackets -->
    <p>
        <label>Add files (up to 2): </label><br/>
        <input type="file" name="example2[]"/><br/>
        <input type="file" name="example2[]"/>
    </p>

    <!-- one file input field that allows multiple files to be uploaded, use brackets -->
    <p>
        <label>Add files (multiple): </label><br/>
        <input type="file" name="example3[]" multiple="multiple"/>
    </p>

    <p>
        <input type="submit"/>
    </p>
</form>

<?php

use DI\ContainerBuilder;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\UploadedFileInterface;
use Slim\Factory\AppFactory;

require __DIR__ . '/../vendor/autoload.php';

$containerBuilder = new ContainerBuilder();
$container = $containerBuilder->build();

$container->set('upload_directory', __DIR__ . '/uploads');

AppFactory::setContainer($container);
$app = AppFactory::create();

$app->post('/', function (ServerRequestInterface $request, ResponseInterface $response) {
    $directory = $this->get('upload_directory');
    $uploadedFiles = $request->getUploadedFiles();

    // handle single input with single file upload
    $uploadedFile = $uploadedFiles['example1'];
    if ($uploadedFile->getError() === UPLOAD_ERR_OK) {
        $filename = moveUploadedFile($directory, $uploadedFile);
        $response->getBody()->write('Uploaded: ' . $filename . '<br/>');
    }

    // handle multiple inputs with the same key
    foreach ($uploadedFiles['example2'] as $uploadedFile) {
        if ($uploadedFile->getError() === UPLOAD_ERR_OK) {
            $filename = moveUploadedFile($directory, $uploadedFile);
            $response->getBody()->write('Uploaded: ' . $filename . '<br/>');
        }
    }

    // handle single input with multiple file uploads
    foreach ($uploadedFiles['example3'] as $uploadedFile) {
        if ($uploadedFile->getError() === UPLOAD_ERR_OK) {
            $filename = moveUploadedFile($directory, $uploadedFile);
            $response->getBody()->write('Uploaded: ' . $filename . '<br/>');
        }
    }

    return $response;
});

/**
 * Moves the uploaded file to the upload directory and assigns it a unique name
 * to avoid overwriting an existing uploaded file.
 *
 * @param string $directory The directory to which the file is moved
 * @param UploadedFileInterface $uploadedFile The file uploaded file to move
 *
 * @return string The filename of moved file
 */
function moveUploadedFile(string $directory, UploadedFileInterface $uploadedFile)
{
    $extension = pathinfo($uploadedFile->getClientFilename(), PATHINFO_EXTENSION);

    // see http://php.net/manual/en/function.random-bytes.php
    $basename = bin2hex(random_bytes(8));
    $filename = sprintf('%s.%0.8s', $basename, $extension);

    $uploadedFile->moveTo($directory . DIRECTORY_SEPARATOR . $filename);

    return $filename;
}

$app->run();