Initial service DAV module

lib/DavUriMap.php

@@ -0,0 +1,135 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KTXM\ServiceDav;
+
+use DI\Attribute\Inject;
+
+/**
+ * Bidirectional mapping between DAV object URIs (chosen by clients) and entity
+ * identifiers assigned by the provider stores.
+ *
+ * Stored as a pair of JSON files per logical "map" (keyed by a mapId that
+ * encodes tenant / user / calendar-or-addressbook context).  File locking is
+ * used to guard against concurrent modifications.
+ *
+ * This class is intentionally simple: it is a best-effort persistence layer for
+ * single-server deployments.  A database-backed implementation should be
+ * substituted for high-concurrency or multi-node environments.
+ */
+class DavUriMap
+{
+    private string $dir;
+
+    public function __construct(#[Inject('rootDir')] string $rootDir)
+    {
+        $this->dir = $rootDir . '/var/dav';
+    }
+
+    // -------------------------------------------------------------------------
+    // Public API
+    // -------------------------------------------------------------------------
+
+    /**
+     * Look up the provider entity identifier for a given DAV object URI.
+     *
+     * @param string $mapId   Logical map bucket (e.g. "{tenant}:{user}:cal:{calId}")
+     * @param string $objectUri DAV leaf URI (e.g. "abc-123.ics")
+     */
+    public function getEntityId(string $mapId, string $objectUri): ?string
+    {
+        return $this->read($mapId)['obj_to_ent'][$objectUri] ?? null;
+    }
+
+    /**
+     * Look up the DAV object URI for a given provider entity identifier.
+     */
+    public function getObjectUri(string $mapId, string $entityId): ?string
+    {
+        return $this->read($mapId)['ent_to_obj'][(string) $entityId] ?? null;
+    }
+
+    /**
+     * Record a mapping from a DAV object URI to a provider entity identifier.
+     */
+    public function set(string $mapId, string $objectUri, string|int $entityId): void
+    {
+        $entityId = (string) $entityId;
+        $this->update($mapId, static function (array $data) use ($objectUri, $entityId): array {
+            $data['obj_to_ent'][$objectUri] = $entityId;
+            $data['ent_to_obj'][$entityId]  = $objectUri;
+            return $data;
+        });
+    }
+
+    /**
+     * Remove the mapping for a DAV object URI.
+     */
+    public function delete(string $mapId, string $objectUri): void
+    {
+        $this->update($mapId, static function (array $data) use ($objectUri): array {
+            $entityId = $data['obj_to_ent'][$objectUri] ?? null;
+            if ($entityId !== null) {
+                unset($data['ent_to_obj'][$entityId]);
+            }
+            unset($data['obj_to_ent'][$objectUri]);
+            return $data;
+        });
+    }
+
+    // -------------------------------------------------------------------------
+    // Internal helpers
+    // -------------------------------------------------------------------------
+
+    private function mapFile(string $mapId): string
+    {
+        return $this->dir . '/map_' . md5($mapId) . '.json';
+    }
+
+    private function read(string $mapId): array
+    {
+        $file = $this->mapFile($mapId);
+        if (!file_exists($file)) {
+            return ['obj_to_ent' => [], 'ent_to_obj' => []];
+        }
+        $contents = file_get_contents($file);
+        if ($contents === false) {
+            return ['obj_to_ent' => [], 'ent_to_obj' => []];
+        }
+        return json_decode($contents, true) ?? ['obj_to_ent' => [], 'ent_to_obj' => []];
+    }
+
+    private function update(string $mapId, callable $updater): void
+    {
+        if (!is_dir($this->dir)) {
+            mkdir($this->dir, 0750, true);
+        }
+
+        $file = $this->mapFile($mapId);
+        $fh   = fopen($file, 'c+');
+        if ($fh === false) {
+            return;
+        }
+
+        try {
+            flock($fh, LOCK_EX);
+            $contents = stream_get_contents($fh);
+            $data     = json_decode($contents ?: '{}', true)
+                        ?? ['obj_to_ent' => [], 'ent_to_obj' => []];
+            if (!isset($data['obj_to_ent'])) {
+                $data['obj_to_ent'] = [];
+            }
+            if (!isset($data['ent_to_obj'])) {
+                $data['ent_to_obj'] = [];
+            }
+            $data = $updater($data);
+            ftruncate($fh, 0);
+            rewind($fh);
+            fwrite($fh, json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE));
+        } finally {
+            flock($fh, LOCK_UN);
+            fclose($fh);
+        }
+    }
+}