Laravel: Middleware to support multipart/form-data in PUT, PATH and DELETE requests. Deals with one level of form arrays.

HandlePutFormData.php

<?php
namespace App\Http\Middleware;

use Closure;
use Symfony\Component\HttpFoundation\ParameterBag;

/**
 * @author https://github.com/Stunext
 *
 * PHP, and by extension, Laravel does not support multipart/form-data requests when using any request method other than POST.
 * This limits the ability to implement RESTful architectures. This is a middleware for Laravel 5.7 that manually decoding
 * the php://input stream when the request type is PUT, DELETE or PATCH and the Content-Type header is mutlipart/form-data.
 *
 * The implementation is based on an example by [netcoder at stackoverflow](http://stackoverflow.com/a/9469615).
 * This is necessary due to an underlying limitation of PHP, as discussed here: https://bugs.php.net/bug.php?id=55815.
 */
class HandlePutFormData
{
	/**
	 * Handle an incoming request.
	 *
	 * @param  \Illuminate\Http\Request  $request
	 * @param  \Closure  $next
	 * @return mixed
	 */
	public function handle($request, Closure $next)
	{
		if ($request->method() == 'POST' or $request->method() == 'GET') {
			return $next($request);
		}

		if (
			preg_match('/multipart\/form-data/', $request->headers->get('Content-Type')) or
			preg_match('/multipart\/form-data/', $request->headers->get('content-type'))
		) {
			$parameters = $this->decode();
			$request->merge($parameters['inputs']);
			$request->files->add($parameters['files']);
		}

		return $next($request);
	}

	public function decode()
	{
		$this->files = [];
		$this->data = [];
		// Fetch content and determine boundary
		$rawData = file_get_contents('php://input');
		$boundary = substr($rawData, 0, strpos($rawData, "\r\n"));

		// Fetch and process each part
		$parts = array_slice(explode($boundary, $rawData), 1);

		foreach ($parts as $part) {
			// If this is the last part, break
			if ($part == "--\r\n") {
				break;
			}

			// Separate content from headers
			$part = ltrim($part, "\r\n");
			list($rawHeaders, $content) = explode("\r\n\r\n", $part, 2);
			$content = substr($content, 0, strlen($content) - 2);

			// Parse the headers list
			$rawHeaders = explode("\r\n", $rawHeaders);
			$headers = [];

			foreach ($rawHeaders as $header) {
				list($name, $value) = explode(':', $header);
				$headers[strtolower($name)] = ltrim($value, ' ');
			}

			// Parse the Content-Disposition to get the field name, etc.
			if (isset($headers['content-disposition'])) {
				preg_match('/^form-data; *name="([^"]+)"(; *filename="([^"]+)")?/', $headers['content-disposition'], $matches);

				$fieldName = $matches[1];
				$fileName = (isset($matches[3]) ? $matches[3] : null);
				parse_str($fieldName, $fieldNameAsArray);

				// If we have a file, save it. Otherwise, save the data.
				if ($fileName !== null) {
					$localFileName = tempnam(sys_get_temp_dir(), 'sfy');

					file_put_contents($localFileName, $content);

					$fileData = [
						'name' => $fileName,
						'type' => $headers['content-type'],
						'tmp_name' => $localFileName,
						'error' => 0,
						'size' => filesize($localFileName),
					];

					$this->parseFieldName($this->files, array_keys($fieldNameAsArray)[0], array_values($fieldNameAsArray)[0], $fileData);

					// register a shutdown function to cleanup the temporary file
					register_shutdown_function(function () use($localFileName) {
						unlink($localFileName);
					});
				} else {
					$this->parseFieldName($this->data, array_keys($fieldNameAsArray)[0], array_values($fieldNameAsArray)[0], $content);
				}
			}
		}

		$fields = new ParameterBag($this->data);

		return [
			"inputs" => $fields->all(),
			"files" => $this->files
		];
	}

	public function parseFieldName(&$var, $fieldBaseName, $fieldNameAsArray, $content)
	{
		if (empty($fieldNameAsArray)) {
			$var[$fieldBaseName] = $content;
			return;
		}

		foreach ($fieldNameAsArray as $key => $value) {
			if (gettype($value) === 'string') {
				//  TODO: deal with nested arrays
				$var[$fieldBaseName][$key] = $content;
			}
		}
	}
}