Add ErrorHandlerTrait

Author: devanych

src/ErrorHandlerTrait.php

@@ -0,0 +1,131 @@
+<?php
+
+declare(strict_types=1);
+
+namespace HttpSoft\ErrorHandler;
+
+use ErrorException;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Throwable;
+
+use function error_reporting;
+use function get_class;
+use function restore_error_handler;
+use function set_error_handler;
+
+trait ErrorHandlerTrait
+{
+    /**
+     * @var ErrorListenerInterface[]
+     */
+    private array $listeners = [];
+
+    /**
+     * @var ErrorResponseGeneratorInterface
+     */
+    private ErrorResponseGeneratorInterface $responseGenerator;
+
+    /**
+     * Adds an error listener to the queue.
+     *
+     * @param ErrorListenerInterface $listener
+     */
+    public function addListener(ErrorListenerInterface $listener): void
+    {
+        $this->listeners[get_class($listener)] = $listener;
+    }
+
+    /**
+     * Handles errors and exceptions in the layers it wraps.
+     *
+     * When an exception is intercepted, a response with error information is generated and returned;
+     * otherwise, the response returned by `Psr\Http\Server\RequestHandlerInterface` instance is used.
+     *
+     * @param ServerRequestInterface $request
+     * @param RequestHandlerInterface $handler
+     * @return ResponseInterface
+     * @throws ErrorException
+     */
+    private function handleError(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
+    {
+        set_error_handler(static function (int $severity, string $message, string $file, int $line): bool {
+            // https://www.php.net/manual/en/function.error-reporting.php#8866
+            // Usages the defined levels of `error_reporting()`.
+            if (!(error_reporting() & $severity)) {
+                // This error code is not included in `error_reporting()`.
+                return true;
+            }
+
+            throw new ErrorException($message, 0, $severity, $file, $line);
+        });
+
+        try {
+            $response = $handler->handle($request);
+        } catch (Throwable $error) {
+            $this->triggerListeners($error, $request);
+            $response = $this->generateResponse($error, $request);
+        }
+
+        restore_error_handler();
+        return $response;
+    }
+
+    /**
+     * Trigger all error listeners.
+     *
+     * @param Throwable $error
+     * @param ServerRequestInterface $request
+     */
+    private function triggerListeners(Throwable $error, ServerRequestInterface $request): void
+    {
+        foreach ($this->listeners as $listener) {
+            $listener->trigger($error, $request);
+        }
+    }
+
+    /**
+     * Returns a response with a valid status code.
+     *
+     * If the generated response has a valid status code, it will be returned unchanged.
+     *
+     * If the status code of the generated response is invalid, but the error
+     * code is valid, the response code will be changed to an error code.
+     *
+     * If the status code of the generated response and error code are
+     * not valid, a response with the status code 500 is returned.
+     *
+     * @see isValidResponseCode()
+     * @param Throwable $error
+     * @param ServerRequestInterface $request
+     * @return ResponseInterface
+     */
+    private function generateResponse(Throwable $error, ServerRequestInterface $request): ResponseInterface
+    {
+        $response = $this->responseGenerator->generate($error, $request);
+
+        if ($this->isValidResponseCode((int) $response->getStatusCode())) {
+            return $response;
+        }
+
+        if ($this->isValidResponseCode((int) $error->getCode())) {
+            return $response->withStatus((int) $error->getCode());
+        }
+
+        return $response->withStatus(500);
+    }
+
+    /**
+     * Checks whether the response status code is valid or not.
+     *
+     * The valid response status code must be 4xx (client errors) or 5xx (server errors).
+     *
+     * @param int $responseCode
+     * @return bool
+     */
+    private function isValidResponseCode(int $responseCode): bool
+    {
+        return ($responseCode >= 400 && $responseCode < 600);
+    }
+}