Add Config Loader that may fetch values from XML using XPath

composer.json

@@ -71,6 +71,7 @@
         "vimeo/psalm": "^5.11"
     },
     "suggest": {
+        "ext-simplexml": "To load trap.xml",
         "roxblnfk/unpoly": "If you want to remove unnecessary PHP polyfills depend on PHP version."
     }
 }

src/Service/Config/ConfigAttribute.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Buggregator\Trap\Service\Config;
+
+/**
+ * @internal
+ */
+interface ConfigAttribute
+{
+}

src/Service/Config/ConfigLoader.php

@@ -0,0 +1,87 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Buggregator\Trap\Service\Config;
+
+/**
+ * @internal
+ */
+final class ConfigLoader
+{
+    private \SimpleXMLElement|null $xml = null;
+
+    /**
+     * @param null|callable(): non-empty-string $xmlProvider
+     */
+    public function __construct(
+        ?callable $xmlProvider = null,
+    )
+    {
+        // Check SimpleXML extension
+        if (!\extension_loaded('simplexml')) {
+            return;
+        }
+
+        try {
+            $xml = $xmlProvider === null
+                ? \file_get_contents(\dirname(__DIR__, 2) . '/trap.xml')
+                : $xmlProvider();
+        } catch (\Throwable) {
+            return;
+        }
+
+        $this->xml = \is_string($xml) ? \simplexml_load_string($xml) : null;
+    }
+
+    public function hidrate(object $config): void
+    {
+        // Read class properties
+        $reflection = new \ReflectionObject($config);
+        foreach ($reflection->getProperties() as $property) {
+            $attributes = $property->getAttributes(ConfigAttribute::class, \ReflectionAttribute::IS_INSTANCEOF);
+            if (\count($attributes) === 0) {
+                continue;
+            }
+
+            $this->injectValue($config, $property, $attributes);
+        }
+    }
+
+    /**
+     * @param \ReflectionProperty $property
+     * @param array<\ReflectionAttribute> $attributes
+     */
+    private function injectValue(object $config, \ReflectionProperty $property, array $attributes): void
+    {
+        foreach ($attributes as $attribute) {
+            $attribute = $attribute->newInstance();
+
+            $value = match (true) {
+                $attribute instanceof XPath => $this->xml?->xpath($attribute->path),
+                default => null,
+            };
+
+            if ($value === null) {
+                continue;
+            }
+
+            // Cast value to the property type
+            $type = $property->getType();
+            $result = match (true) {
+                $type === null => $value[0],
+                $type->allowsNull() && $value[0] === '' => null,
+                $type->isBuiltin() => match ($type->getName()) {
+                    'int' => (int) $value[0],
+                    'float' => (float) $value[0],
+                    'bool' => \filter_var($value[0], FILTER_VALIDATE_BOOLEAN),
+                    default => $value[0],
+                },
+                default => $value[0],
+            };
+
+            // Set the property value
+            $property->setValue($config, $result);
+        }
+    }
+}

src/Service/Config/XPath.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Buggregator\Trap\Service\Config;
+
+/**
+ * @internal
+ */
+#[\Attribute(\Attribute::TARGET_PROPERTY)]
+final class XPath implements ConfigAttribute
+{
+    public function __construct(
+        public string $path,
+    ) {
+    }
+}

tests/Unit/Service/Config/ConfigLoaderTest.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Buggregator\Trap\Tests\Unit\Service\Config;
+
+use Buggregator\Trap\Service\Config\ConfigLoader;
+use Buggregator\Trap\Service\Config\XPath;
+use PHPUnit\Framework\TestCase;
+
+final class ConfigLoaderTest extends TestCase
+{
+    public function testSimpleHydration(): void
+    {
+        $dto = new class() {
+            #[XPath('/trap/container/@myBool')]
+            public bool $myBool;
+            #[XPath('/trap/container/MyInt/@value')]
+            public int $myInt;
+            #[XPath('/trap/@my-string')]
+            public string $myString;
+            #[XPath('/trap/container/MyFloat/@value')]
+            public float $myFloat;
+        };
+
+        $xml = <<<'XML'
+            <?xml version="1.0"?>
+            <trap my-string="foo-bar">
+                <container myBool="true">
+                    <MyInt value="200"/>
+                    <MyFloat value="42"/>
+                </container>
+            </trap>
+            XML;
+
+        $loader = new ConfigLoader(fn() => $xml);
+        $loader->hidrate($dto);
+
+        self::assertTrue($dto->myBool);
+        self::assertSame(200, $dto->myInt);
+        self::assertSame('foo-bar', $dto->myString);
+        self::assertSame(42.0, $dto->myFloat);
+    }
+}

trap.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0"?>
+<trap>
+    <frontend port="8000">
+        <EventsBuffer maxSize="200"/>
+    </frontend>
+</trap>