UHF-6197: Trait to generate cache keys

src/Cache/CacheKeyTrait.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\helfi_api_base\Cache;
+
+/**
+ * A helper trait to generate cache keys.
+ */
+trait CacheKeyTrait {
+
+  /**
+   * Converts an array of request options to cache key.
+   *
+   * @param string $baseKey
+   *   The base key.
+   * @param array $options
+   *   The options.
+   *
+   * @return string
+   *   The flattened cache key.
+   */
+  protected function requestOptionsToCacheKey(string $baseKey, array $options) : string {
+    foreach ($options as $key => $value) {
+      // We only care about string keys.
+      if (is_string($key)) {
+        $baseKey .= sprintf('%s=', $key);
+      }
+      if (is_array($value)) {
+        $baseKey .= $this->requestOptionsToCacheKey('', $value);
+      }
+      elseif (is_scalar($value)) {
+        $baseKey .= $value;
+      }
+      $baseKey .= ';';
+    }
+    return rtrim($baseKey, ';');
+  }
+
+  /**
+   * Gets the cache key for given base key and request options.
+   *
+   * @param string $baseKey
+   *   The base key.
+   * @param array $options
+   *   The request options.
+   *
+   * @return string
+   *   The cache key.
+   */
+  protected function getCacheKey(string $baseKey, array $options = []) : string {
+    return rtrim(
+      sprintf('%s:%s', $baseKey, $this->requestOptionsToCacheKey('', $options)),
+      ':'
+    );
+  }
+
+}

tests/src/Unit/Cache/CacheKeyTraitTest.php

@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\Tests\helfi_api_base\Unit;
+
+use Drupal\helfi_api_base\Cache\CacheKeyTrait;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * Tests cache key trait.
+ *
+ * @group helfi_api_base
+ */
+class CacheKeyTraitTest extends UnitTestCase {
+
+  use CacheKeyTrait;
+
+  /**
+   * @covers \Drupal\helfi_api_base\Cache\CacheKeyTrait::getCacheKey
+   * @covers \Drupal\helfi_api_base\Cache\CacheKeyTrait::requestOptionsToCacheKey
+   * @dataProvider cacheKeyData
+   */
+  public function testGetCacheKey(string $expected, string $baseKey, array $options) : void {
+    $actual = $this->getCacheKey($baseKey, $options);
+    $this->assertEquals($expected, $actual);
+  }
+
+  /**
+   * Data provider for testRequestOptionsToCacheKey().
+   *
+   * @return array[]
+   *   The data.
+   */
+  public function cacheKeyData() : array {
+    return [
+      [
+        'test:1',
+        'test:1',
+        [],
+      ],
+      [
+        'test:2:key=value',
+        'test:2',
+        [
+          'key' => 'value',
+        ],
+      ],
+      [
+        'test:3:value;key=value',
+        'test:3',
+        [
+          'value',
+          [
+            'key' => 'value',
+          ],
+        ],
+      ],
+      [
+        ':key1=value1;key2=value2;key3=value3',
+        '',
+        [
+          'key1' => 'value1',
+          'key2' => ['value2', 'key3' => 'value3'],
+        ],
+      ],
+      // Make sure non-scalar values are ignored.
+      [
+        'test:4:value',
+        'test:4',
+        [
+          'value',
+          [
+            (object) ['key' => 'value'],
+          ],
+        ],
+      ],
+    ];
+  }
+
+}