From 6591f2cf68887e24da87fbb755e4f2c1a7ce8190 Mon Sep 17 00:00:00 2001
From: Michael Babker <michael@happydog.digital>
Date: Wed, 13 Dec 2023 17:37:06 -0500
Subject: [PATCH] Add an error URI resolver

---
 src/WAMP/DefaultErrorUriResolver.php          | 34 +++++++++++++++++++
 src/WAMP/ErrorUriResolver.php                 | 27 +++++++++++++++
 .../Middleware/DispatchMessageToHandler.php   |  7 ++--
 tests/WAMP/DefaultErrorUriResolverTest.php    | 30 ++++++++++++++++
 4 files changed, 96 insertions(+), 2 deletions(-)
 create mode 100644 src/WAMP/DefaultErrorUriResolver.php
 create mode 100644 src/WAMP/ErrorUriResolver.php
 create mode 100644 tests/WAMP/DefaultErrorUriResolverTest.php

diff --git a/src/WAMP/DefaultErrorUriResolver.php b/src/WAMP/DefaultErrorUriResolver.php
new file mode 100644
index 0000000..69a9f03
--- /dev/null
+++ b/src/WAMP/DefaultErrorUriResolver.php
@@ -0,0 +1,34 @@
+<?php declare(strict_types=1);
+
+namespace BabDev\WebSocket\Server\WAMP;
+
+use BabDev\WebSocket\Server\WAMP\Middleware\DispatchMessageToHandler;
+
+/**
+ * The error URI resolver is responsible for resolving URIs for identifying errors,
+ * which is provided as part of the "CALLERROR" WAMP message to the client.
+ */
+final readonly class DefaultErrorUriResolver implements ErrorUriResolver
+{
+    /**
+     * Resolve the error URI or CURIE for the given error type.
+     *
+     * Because the types of errors will be application dependent other than the "handler not found"
+     * scenario in the default {@see DispatchMessageToHandler} middleware, a predefined list of error
+     * types is not provided by this library. However, implementations should at a minimum support the
+     * "not-found" type, and must return a generic type if they do not support creating a URI for a
+     * specific type of error.
+     *
+     * @param non-empty-string $errorType
+     *
+     * @return non-empty-string
+     */
+    public function resolve(string $errorType): string
+    {
+        if ($errorType === 'not-found') {
+            return 'https://example.com/error#not-found';
+        }
+
+        return 'https://example.com/error#generic';
+    }
+}
diff --git a/src/WAMP/ErrorUriResolver.php b/src/WAMP/ErrorUriResolver.php
new file mode 100644
index 0000000..323e79f
--- /dev/null
+++ b/src/WAMP/ErrorUriResolver.php
@@ -0,0 +1,27 @@
+<?php declare(strict_types=1);
+
+namespace BabDev\WebSocket\Server\WAMP;
+
+use BabDev\WebSocket\Server\WAMP\Middleware\DispatchMessageToHandler;
+
+/**
+ * The error URI resolver is responsible for resolving URIs for identifying errors,
+ * which is provided as part of the "CALLERROR" WAMP message to the client.
+ */
+interface ErrorUriResolver
+{
+    /**
+     * Resolve the error URI or CURIE for the given error type.
+     *
+     * Because the types of errors will be application dependent other than the "handler not found"
+     * scenario in the default {@see DispatchMessageToHandler} middleware, a predefined list of error
+     * types is not provided by this library. However, implementations should at a minimum support the
+     * "not-found" type, and must return a generic type if they do not support creating a URI for a
+     * specific type of error.
+     *
+     * @param non-empty-string $errorType
+     *
+     * @return non-empty-string
+     */
+    public function resolve(string $errorType): string;
+}
diff --git a/src/WAMP/Middleware/DispatchMessageToHandler.php b/src/WAMP/Middleware/DispatchMessageToHandler.php
index 5905c3d..f88c32d 100644
--- a/src/WAMP/Middleware/DispatchMessageToHandler.php
+++ b/src/WAMP/Middleware/DispatchMessageToHandler.php
@@ -11,6 +11,8 @@
 use BabDev\WebSocket\Server\RPCMessageMiddleware;
 use BabDev\WebSocket\Server\TopicMessageHandler;
 use BabDev\WebSocket\Server\TopicMessageMiddleware;
+use BabDev\WebSocket\Server\WAMP\DefaultErrorUriResolver;
+use BabDev\WebSocket\Server\WAMP\ErrorUriResolver;
 use BabDev\WebSocket\Server\WAMP\Exception\CannotInstantiateMessageHandler;
 use BabDev\WebSocket\Server\WAMP\Exception\InvalidMessageHandler;
 use BabDev\WebSocket\Server\WAMP\Exception\InvalidRequest;
@@ -47,6 +49,7 @@ public function __construct(
         private UrlMatcherInterface $matcher,
         private MessageHandlerResolver $resolver,
         private ?EventDispatcherInterface $dispatcher = null,
+        private ErrorUriResolver $errorUriResolver = new DefaultErrorUriResolver(),
     ) {}
 
     /**
@@ -110,7 +113,7 @@ public function onCall(WAMPConnection $connection, string $id, string $resolvedU
         } catch (RouteNotFound $exception) {
             $connection->callError(
                 $id,
-                'https://example.com/error#not-found', // TODO - Make the error URI customizable
+                $this->errorUriResolver->resolve('not-found'),
                 sprintf('Could not find a message handler for URI "%s".', $resolvedUri),
                 [
                     'code' => 404,
@@ -126,7 +129,7 @@ public function onCall(WAMPConnection $connection, string $id, string $resolvedU
         } catch (WebSocketException $exception) {
             $connection->callError(
                 $id,
-                'https://example.com/error#not-found', // TODO - Make the error URI customizable
+                $this->errorUriResolver->resolve('not-found'),
                 sprintf('Could not find a message handler for URI "%s".', $resolvedUri),
                 [
                     'code' => 404,
diff --git a/tests/WAMP/DefaultErrorUriResolverTest.php b/tests/WAMP/DefaultErrorUriResolverTest.php
new file mode 100644
index 0000000..245ab03
--- /dev/null
+++ b/tests/WAMP/DefaultErrorUriResolverTest.php
@@ -0,0 +1,30 @@
+<?php declare(strict_types=1);
+
+namespace BabDev\WebSocket\Server\Tests\WAMP;
+
+use BabDev\WebSocket\Server\WAMP\DefaultErrorUriResolver;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+final class DefaultErrorUriResolverTest extends TestCase
+{
+    /**
+     * @return \Generator<string, array{non-empty-string, non-empty-string}>
+     */
+    public static function dataSupportedErrors(): \Generator
+    {
+        yield '"not-found" error' => ['not-found', 'https://example.com/error#not-found'];
+
+        yield 'Unknown error' => ['unknown', 'https://example.com/error#generic'];
+    }
+
+    /**
+     * @param non-empty-string $errorType
+     * @param non-empty-string $expected
+     */
+    #[DataProvider('dataSupportedErrors')]
+    public function testResolve(string $errorType, string $expected): void
+    {
+        $this->assertSame($expected, (new DefaultErrorUriResolver())->resolve($errorType));
+    }
+}