Custom request body parsers, spunoff from reactphp/http#220 (comment)

Author: WyriHaximus

composer.json

@@ -0,0 +1,12 @@
+{
+    "name": "wyrihaximus/custom-request-body-parsers",
+    "require": {
+        "php": "^7.0",
+        "psr/http-message": "^1.0"
+    },
+    "autoload": {
+        "psr-4": {
+            "WyriHaximus\\React\\Http\\Middleware\\": "src/"
+        }
+    }
+}

composer.lock

@@ -0,0 +1,67 @@
+<?php
+
+namespace WyriHaximus\React\Http\Middleware;
+
+use Psr\Http\Message\ServerRequestInterface;
+final class CustomRequestBodyParsers
+{
+    private $types = array();
+
+    public function __construct()
+    {
+        /**
+         * Via: https://github.com/reactphp/http/pull/220#discussion_r140863176
+         */
+        $this->addType('application/json', function (ServerRequestInterface $request) {
+            $result = json_decode((string)$request->getBody(), true);
+            if (!is_array($result)) {
+                return null;
+            }
+            return $result;
+        });
+
+        /**
+         * Via: https://github.com/reactphp/http/pull/220#discussion_r140863176
+         */
+        $xmlParser = function (ServerRequestInterface $request) {
+            $backup = libxml_disable_entity_loader(true);
+            $backup_errors = libxml_use_internal_errors(true);
+            $result = simplexml_load_string((string)$request->getBody());
+            libxml_disable_entity_loader($backup);
+            libxml_clear_errors();
+            libxml_use_internal_errors($backup_errors);
+            if ($result === false) {
+                return $request;
+            }
+            return $request->withParsedBody($result);
+        };
+        $this->addType('application/xml', $xmlParser);
+        $this->addType('text/xml', $xmlParser);
+    }
+
+    public function addType($type, $callback)
+    {
+        $this->types[$type] = $callback;
+    }
+
+    public function __invoke(ServerRequestInterface $request, $next)
+    {
+        $type = $request->getHeaderLine('Content-Type');
+
+        if (!isset($this->types[$type])) {
+            return $next($request);
+        }
+
+        try {
+            $parser = $this->types[$type];
+            /** @var ServerRequestInterface $request */
+            $request = $parser($request);
+        } catch (\Exception $e) {
+            return $next($request);
+        } catch (\Throwable $t) {
+            return $next($request);
+        }
+
+        return $next($request);
+    }
+}