From 0d42024f02314f9d9b788c643b76cdba2fece6f8 Mon Sep 17 00:00:00 2001
From: Ashley Marques <marques.ashley@gmail.com>
Date: Sat, 10 Jun 2023 10:32:35 -0300
Subject: [PATCH 1/2] change conn string

---
 .../DatabaseOperations.cs                     | 55 +++++++++++++++----
 1 file changed, 43 insertions(+), 12 deletions(-)

diff --git a/Extensions.Caching.PostgreSql/DatabaseOperations.cs b/Extensions.Caching.PostgreSql/DatabaseOperations.cs
index d5166ca..e59bf21 100644
--- a/Extensions.Caching.PostgreSql/DatabaseOperations.cs
+++ b/Extensions.Caching.PostgreSql/DatabaseOperations.cs
@@ -19,7 +19,7 @@ internal sealed class DatabaseOperations : IDatabaseOperations
 
         public DatabaseOperations(IOptions<PostgreSqlCacheOptions> options, ILogger<DatabaseOperations> logger)
         {
-            var cacheOptions = options.Value;
+            cacheOptions = options.Value;
 
             if (string.IsNullOrEmpty(cacheOptions.ConnectionString))
             {
@@ -37,7 +37,7 @@ public DatabaseOperations(IOptions<PostgreSqlCacheOptions> options, ILogger<Data
                     $"{nameof(PostgreSqlCacheOptions.TableName)} cannot be empty or null.");
             }
 
-            ConnectionString = cacheOptions.ConnectionString;
+            _connectionString = cacheOptions.ConnectionString;
             SystemClock = cacheOptions.SystemClock;
 
             SqlCommands = new SqlCommands(cacheOptions.SchemaName, cacheOptions.TableName);
@@ -50,14 +50,45 @@ public DatabaseOperations(IOptions<PostgreSqlCacheOptions> options, ILogger<Data
         }
 
         private SqlCommands SqlCommands { get; }
+        private string _connectionString;
+        private readonly PostgreSqlCacheOptions cacheOptions;
+        private ISystemClock SystemClock { get; }
 
-        private string ConnectionString { get; }
+        /// <summary>
+        /// Modify current conection string 
+        /// </summary>
+        /// <param name="newConnectionString">the new connection string to replace </param>
+        public void ChangeConnectionString(string newConnectionString)
+        {
+            string original = _connectionString;
+            try
+            {
+                using var newConnection = new NpgsqlConnection(newConnectionString);
+                newConnection.Open();
+                bool connected = newConnection.ExecuteScalar<bool>("SELECT 1=1;");
+                if (connected)
+                {
+                    _connectionString = newConnectionString;
+                    _logger.LogDebug("ChangeConnectionString: new connection is valid and is use");
+                }
+                newConnection.Close();
+                if (cacheOptions.CreateInfrastructure)
+                {
+                    CreateSchemaAndTableIfNotExist();
+                }
+            }
+            catch (System.Exception ex)
+            {
+                _connectionString = original;
+                throw new InvalidOperationException("ChangeConnectionString failed.\nPrevious connection restored.", ex);
+            }
 
-        private ISystemClock SystemClock { get; }
+
+        }
 
         private void CreateSchemaAndTableIfNotExist()
         {
-            using (var connection = new NpgsqlConnection(ConnectionString))
+            using (var connection = new NpgsqlConnection(_connectionString))
             {
                 connection.Open();
                 using (var transaction = connection.BeginTransaction())
@@ -76,7 +107,7 @@ private void CreateSchemaAndTableIfNotExist()
 
         public void DeleteCacheItem(string key)
         {
-            using var connection = new NpgsqlConnection(ConnectionString);
+            using var connection = new NpgsqlConnection(_connectionString);
 
             var deleteCacheItem = new CommandDefinition(
                 SqlCommands.DeleteCacheItemSql,
@@ -88,7 +119,7 @@ public void DeleteCacheItem(string key)
 
         public async Task DeleteCacheItemAsync(string key, CancellationToken cancellationToken)
         {
-            await using var connection = new NpgsqlConnection(ConnectionString);
+            await using var connection = new NpgsqlConnection(_connectionString);
 
             var deleteCacheItem = new CommandDefinition(
                 SqlCommands.DeleteCacheItemSql,
@@ -116,7 +147,7 @@ public async Task DeleteExpiredCacheItemsAsync(CancellationToken cancellationTok
         {
             var utcNow = SystemClock.UtcNow;
 
-            await using var connection = new NpgsqlConnection(ConnectionString);
+            await using var connection = new NpgsqlConnection(_connectionString);
 
             var deleteExpiredCache = new CommandDefinition(
                 SqlCommands.DeleteExpiredCacheSql,
@@ -132,7 +163,7 @@ public void SetCacheItem(string key, byte[] value, DistributedCacheEntryOptions
             var absoluteExpiration = GetAbsoluteExpiration(utcNow, options);
             ValidateOptions(options.SlidingExpiration, absoluteExpiration);
 
-            using var connection = new NpgsqlConnection(ConnectionString);
+            using var connection = new NpgsqlConnection(_connectionString);
 
             var expiresAtTime = options.SlidingExpiration == null
                 ? absoluteExpiration!.Value
@@ -159,7 +190,7 @@ public async Task SetCacheItemAsync(string key, byte[] value, DistributedCacheEn
             var absoluteExpiration = GetAbsoluteExpiration(utcNow, options);
             ValidateOptions(options.SlidingExpiration, absoluteExpiration);
 
-            await using var connection = new NpgsqlConnection(ConnectionString);
+            await using var connection = new NpgsqlConnection(_connectionString);
 
             var expiresAtTime = options.SlidingExpiration == null
                 ? absoluteExpiration!.Value
@@ -185,7 +216,7 @@ private byte[] GetCacheItem(string key, bool includeValue)
             var utcNow = SystemClock.UtcNow;
             byte[] value = null;
 
-            using var connection = new NpgsqlConnection(ConnectionString);
+            using var connection = new NpgsqlConnection(_connectionString);
 
             var updateCacheItem = new CommandDefinition(
                 SqlCommands.UpdateCacheItemSql,
@@ -208,7 +239,7 @@ private async Task<byte[]> GetCacheItemAsync(string key, bool includeValue, Canc
             var utcNow = SystemClock.UtcNow;
             byte[] value = null;
 
-            await using var connection = new NpgsqlConnection(ConnectionString);
+            await using var connection = new NpgsqlConnection(_connectionString);
 
             var updateCacheItem = new CommandDefinition(
                 SqlCommands.UpdateCacheItemSql,

From ae9ca0f3878e1fead878c5b7f979d7068dbe4332 Mon Sep 17 00:00:00 2001
From: Ashley Marques <marques.ashley@gmail.com>
Date: Sat, 10 Jun 2023 10:38:08 -0300
Subject: [PATCH 2/2] modify interface

---
 Extensions.Caching.PostgreSql/IDatabaseOperations.cs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Extensions.Caching.PostgreSql/IDatabaseOperations.cs b/Extensions.Caching.PostgreSql/IDatabaseOperations.cs
index 68d529c..559ed97 100644
--- a/Extensions.Caching.PostgreSql/IDatabaseOperations.cs
+++ b/Extensions.Caching.PostgreSql/IDatabaseOperations.cs
@@ -26,5 +26,6 @@ public interface IDatabaseOperations
         Task SetCacheItemAsync(string key, byte[] value, DistributedCacheEntryOptions options, CancellationToken cancellationToken);
 
         Task DeleteExpiredCacheItemsAsync(CancellationToken cancellationToken);
+        void ChangeConnectionString(string newConnectionString);
     }
 }
\ No newline at end of file