Make ConnectionString settable again (#98)

* Make ConnectionString settable again

* Make database setting mutable to support changing db for open connections

Author: alex-clickhouse

ClickHouse.Driver.Tests/ADO/ConnectionTests.cs

@@ -47,6 +47,26 @@ public async Task ShouldCreateConnectionWithSkipServerCertificateValidation()
         Assert.That(conn.SkipServerCertificateValidation, Is.True);
     }
 
+    [Test]
+    public async Task ShouldBeAbleToSetConnectionStringAfterCreation() // Necessary to support this for some scenarios involving ClickHouseConnectionFactory
+    {
+        var conn = new ClickHouseConnection();
+        conn.ConnectionString = TestUtilities.GetConnectionStringBuilder().ToString();
+        await conn.OpenAsync();
+
+        Assert.That(conn.State, Is.EqualTo(ConnectionState.Open));
+    }
+
+    [Test]
+    public async Task ShouldNotBeAbleToSetConnectionStringWhileOpen()
+    {
+        using var conn = new ClickHouseConnection(TestUtilities.GetConnectionStringBuilder().ToString());
+        await conn.OpenAsync();
+
+        Assert.That(conn.State, Is.EqualTo(ConnectionState.Open));
+        Assert.Throws<InvalidOperationException>(() => conn.ConnectionString = "Host=otherhost");
+    }
+
     [Test]
     public void ShouldParseCustomParameter()
     {

ClickHouse.Driver/ADO/ClickHouseClientSettings.cs

@@ -93,7 +93,7 @@ public ClickHouseClientSettings(ClickHouseClientSettings other)
     /// Gets or sets the database name.
     /// Default: "" (if empty, will use the user's default database if it has been configured).
     /// </summary>
-    public string Database { get; init; } = ClickHouseDefaults.Database;
+    public string Database { get; set; } = ClickHouseDefaults.Database;
 
     /// <summary>
     /// Gets or sets the path component of the URL (for reverse proxy scenarios).

ClickHouse.Driver/ADO/ClickHouseConnection.cs

@@ -59,7 +59,7 @@ public ClickHouseConnection(string connectionString, bool skipServerCertificateV
             SkipServerCertificateValidation = skipServerCertificateValidation,
         };
 
-        ApplySettings(settings);
+        Settings = settings;
     }
 
     /// <summary>
@@ -75,7 +75,7 @@ public ClickHouseConnection(string connectionString, HttpClient httpClient)
             HttpClient = httpClient,
         };
 
-        ApplySettings(settings);
+        Settings = settings;
     }
 
     /// <summary>
@@ -121,7 +121,7 @@ public ClickHouseConnection(string connectionString, IHttpClientFactory httpClie
             HttpClientName = httpClientName,
         };
 
-        ApplySettings(settings);
+        Settings = settings;
     }
 
     /// <summary>
@@ -132,8 +132,7 @@ public ClickHouseConnection(ClickHouseClientSettings settings)
     {
         if (settings == null)
             throw new ArgumentNullException(nameof(settings));
-
-        ApplySettings(settings);
+        Settings = settings;
     }
 
     private ILoggerFactory loggerFactory;
@@ -158,15 +157,24 @@ internal ILogger GetLogger(string categoryName)
     /// <summary>
     /// Gets the string defining connection settings for ClickHouse server
     /// Example: Host=localhost;Port=8123;Username=default;Password=123;Compression=true
-    /// Setting the connection string is not supported; create a new connection with the desired settings instead.
+    /// It is generally recommended create a new connection instead of modifying the settings of an existing one.
     /// </summary>
     public sealed override string ConnectionString
     {
         get => ConnectionStringBuilder.ToString();
-        set => throw new NotSupportedException("Connection string cannot be changed after construction. Create a new connection with the desired settings.");
+        set => Settings = new ClickHouseClientSettings(value);
     }
 
-    public ClickHouseClientSettings Settings { get; private set; }
+    public ClickHouseClientSettings Settings { get;
+        set
+        {
+            if (State == ConnectionState.Open)
+                throw new InvalidOperationException("Cannot change settings while connection is open.");
+            
+            field = value;
+            ApplySettings();
+        }
+    }
 
     public IDictionary<string, object> CustomSettings => Settings?.CustomSettings;
 
@@ -210,26 +218,26 @@ public virtual Feature SupportedFeatures
         private set => supportedFeatures = value;
     }
 
-    private void ApplySettings(ClickHouseClientSettings settings)
+    private void ApplySettings()
     {
-        settings.Validate();
-        Settings = settings;
+        Settings.Validate();
 
-        serverUri = new UriBuilder(settings.Protocol, settings.Host, settings.Port, settings.Path ?? string.Empty).Uri;
+        serverUri = new UriBuilder(Settings.Protocol, Settings.Host, Settings.Port, Settings.Path ?? string.Empty).Uri;
 
         // HttpClientFactory/HttpClient
-        providedHttpClient = settings.HttpClient;
-        providedHttpClientFactory = settings.HttpClientFactory;
-        httpClientName = settings.HttpClientName;
+        providedHttpClient = Settings.HttpClient;
+        providedHttpClientFactory = Settings.HttpClientFactory;
+        httpClientName = Settings.HttpClientName;
 
         // Logging
-        loggerFactory = settings.LoggerFactory;
+        loggerCache.Clear();
+        loggerFactory = Settings.LoggerFactory;
 
 #if NET5_0_OR_GREATER
         // Debug mode
-        if (settings.EnableDebugMode)
+        if (Settings.EnableDebugMode)
         {
-            TraceHelper.Activate(settings.LoggerFactory);
+            TraceHelper.Activate(Settings.LoggerFactory);
         }
 #endif
 
@@ -299,10 +307,7 @@ internal static async Task<HttpResponseMessage> HandleError(HttpResponseMessage
 
     public override void ChangeDatabase(string databaseName)
     {
-        Settings = new ClickHouseClientSettings(Settings)
-        {
-            Database = databaseName,
-        };
+        Settings.Database = databaseName;
     }
 
     public object Clone() => new ClickHouseConnection(ConnectionString);

RELEASENOTES.md

@@ -3,7 +3,7 @@ v0.8.2
 
 **Breaking Changes:**
  * Removed obsolete MySQL compatibility mapping TIME -> Int64.
- * Json serialization of bool arrays now uses the Boolean type instead of UInt8, and is now consistent with bool elements.
+ * Json serialization of bool arrays now uses the Boolean type instead of UInt8 (it is now consistent with how bool values outside arrays were handled).
 
 **New Features/Improvements:**
  * Added support for BFloat16. It is converted to and from a 32-bit float.
@@ -13,8 +13,10 @@ v0.8.2
    * Now supports parsing Json that includes Maps; they are read into JsonObjects.
    * Added support for decoding BigInteger types, UUID, IPv4, IPv6, and ClickHouseDecimal types (they are handled as strings).
    * Expanded binary parsing to cover all types.
-   * Improved handling of numeric types: now properly detects and preserves integer vs floating-point types (previously all numeric types were handled as double).
-   * Null values in arrays are now handled properly.
+   * Improved handling of numeric types when writing Json using BulkCopy: now properly detects and preserves Int32/In64 in addition to double (previously all numeric types were handled as double).
+   * Parsing null values in arrays is now handled properly.
+ * ClickHouseConnection.ConnectionString can now be set after creating the connection, to support cases where passing the connection string to the constructor is not possible.
+ * ClickHouseConnection.CreateCommand() now has an optional argument for the command text.
 
 **Bug Fixes:**
  * Fixed a bug where serializing to json with an array of bools with both true and false elements would fail.