Dactyloidae iOS initial commit

mobile/ios/Storage/SQL/SQLiteMetadata.swift

@@ -0,0 +1,58 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import Foundation
+import Deferred
+import Shared
+
+/// The sqlite-backed implementation of the metadata protocol containing images and content for pages.
+open class SQLiteMetadata {
+    let db: BrowserDB
+
+    required public init(db: BrowserDB) {
+        self.db = db
+    }
+}
+
+extension SQLiteMetadata: Metadata {
+    // A cache key is a conveninent, readable identifier for a site in the metadata database which helps
+    // with deduping entries for the same page.
+    typealias CacheKey = String
+
+    /// Persists the given PageMetadata object to browser.db in the page_metadata table.
+    ///
+    /// - parameter metadata: Metadata object
+    /// - parameter pageURL:  URL of page metadata was fetched from
+    /// - parameter expireAt: Expiration/TTL interval for when this metadata should expire at.
+    ///
+    /// - returns: Deferred on success
+    public func storeMetadata(_ metadata: PageMetadata, forPageURL pageURL: URL,
+                              expireAt: UInt64) -> Success {
+        guard let cacheKey = pageURL.displayURL?.absoluteString else {
+            return succeed()
+        }
+
+        // Replace any matching cache_key entries if they exist
+        let selectUniqueCacheKey = "COALESCE((SELECT cache_key FROM \(TablePageMetadata) WHERE cache_key = ?), ?)"
+        let args: Args = [cacheKey, cacheKey, metadata.siteURL, metadata.mediaURL, metadata.title,
+                          metadata.type, metadata.description, metadata.providerName,
+                          expireAt]
+
+        let insert =
+        "INSERT OR REPLACE INTO \(TablePageMetadata)" +
+        "(cache_key, site_url, media_url, title, type, description, provider_name, expired_at) " +
+        "VALUES ( \(selectUniqueCacheKey), ?, ?, ?, ?, ?, ?, ?)"
+
+        return self.db.run(insert, withArgs: args)
+    }
+
+    /// Purges any metadata items living in page_metadata that are expired.
+    ///
+    /// - returns: Deferred on success
+    public func deleteExpiredMetadata() -> Success {
+        let sql = "DELETE FROM page_metadata WHERE expired_at <= (CAST(strftime('%s', 'now') AS LONG)*1000)"
+        return self.db.run(sql)
+    }
+
+}