Adding the ability to manually restore a database from a file.

SqliteWasmHelper/BrowserCache.cs

@@ -48,6 +48,18 @@ public async Task<int> SyncDbWithCacheAsync(string filename)
             return await module.InvokeAsync<int>("synchronizeDbWithCache", filename);
         }
 
+        /// <summary>
+        /// Calls the code to restore the database from a given ArrayBuffer.
+        /// </summary>
+        /// <param name="arrayBuffer">The ArrayBuffer containing the database file.</param>
+        /// <param name="filename">The name of the file to process.</param>
+        /// <returns>0 if successful, -1 otherwise.</returns>
+        public async Task<int> ManualRestore(byte[] arrayBuffer, string filename)
+        {
+            var module = await moduleTask.Value;
+            return await module.InvokeAsync<int>("manualRestore", arrayBuffer, filename);
+        }
+
         /// <summary>
         /// Creates an anchor tag to download the database and injects it into the parent.
         /// </summary>

SqliteWasmHelper/IBrowserCache.cs

@@ -18,6 +18,14 @@ public interface IBrowserCache
         /// <returns>Either -1 (no cache), 0 (restored), or 1 (cached).</returns>
         Task<int> SyncDbWithCacheAsync(string filename);
 
+        /// <summary>
+        /// Calls the code to restore the database from a given ArrayBuffer.
+        /// </summary>
+        /// <param name="arrayBuffer">The ArrayBuffer containing the database file.</param>
+        /// <param name="filename">The name of the file to process.</param>
+        /// <returns>0 if successful, -1 otherwise.</returns>
+        Task<int> ManualRestore(byte[] arrayBuffer, string filename);
+
         /// <summary>
         /// Creates an anchor tag to download the database and injects it into the parent.
         /// </summary>

SqliteWasmHelper/ISqliteWasmDbContextFactory.cs

@@ -18,5 +18,12 @@ public interface ISqliteWasmDbContextFactory<TContext>
         /// </summary>
         /// <returns>The new context.</returns>
         Task<TContext> CreateDbContextAsync();
+
+        /// <summary>
+        /// Calls the code to restore the database from a given ArrayBuffer.
+        /// </summary>
+        /// <param name="arrayBuffer">The ArrayBuffer containing the database file.</param>
+        /// <returns>0 if successful, -1 otherwise.</returns>
+        Task<int> ManualRestore(byte[] arrayBuffer);
     }
 }

SqliteWasmHelper/SqliteWasmDbContextFactory.cs

@@ -99,6 +99,23 @@ public async Task<TContext> CreateDbContextAsync()
             return ctx;
         }
 
+        /// <summary>
+        /// Calls the code to restore the database from a given ArrayBuffer.
+        /// </summary>
+        /// <param name="arrayBuffer">The ArrayBuffer containing the database file.</param>
+        /// <returns>0 if successful, -1 otherwise.</returns>
+        public async Task<int> ManualRestore(byte[] arrayBuffer)
+        {
+            var filename = $"{GetFilename()}_bak";
+            int restoreStatus = await cache.ManualRestore(arrayBuffer, filename);
+            if (restoreStatus == 0)
+            {
+                DoSwap(filename, FileNames[typeof(TContext)]);
+            }
+
+            return restoreStatus;
+        }
+
         private void DoSwap(string source, string target) =>
             swap.DoSwap(source, target);
 

SqliteWasmHelper/wwwroot/browserCache.js

@@ -86,3 +86,40 @@ export async function generateDownloadLink(parent, file) {
 
     return false;
 }
+
+export async function manualRestore(arrayBuffer, file) {
+    window.sqlitedb = window.sqlitedb || {
+        init: false,
+        cache: await caches.open('SqliteWasmHelper')
+    };
+
+    const db = window.sqlitedb;
+
+    const backupPath = `/${file}`;
+    const cachePath = `/data/cache/${file.substring(0, file.indexOf('_bak'))}`;
+
+    if (arrayBuffer) {
+        console.log(`Restoring ${arrayBuffer.byteLength} bytes.`);
+        window.Module.FS.writeFile(backupPath, new Uint8Array(arrayBuffer));
+
+        const blob = new Blob([arrayBuffer], {
+            type: 'application/octet-stream',
+            ok: true,
+            status: 200
+        });
+
+        const headers = new Headers({
+            'content-length': blob.size
+        });
+
+        const response = new Response(blob, {
+            headers
+        });
+
+        await db.cache.put(cachePath, response);
+
+        return 0;
+    }
+
+    return -1;
+}

SqliteWasmTests/TestHelpers/MockBrowserCache.cs

@@ -52,5 +52,10 @@ public Task<int> SyncDbWithCacheAsync(string filename)
             }
             return Task.FromResult(SyncDbResult);
         }
+
+        public Task<int> ManualRestore(byte[] arrayBuffer, string filename)
+        {
+            throw new System.NotImplementedException();
+        }
     }
 }