Added ability to specify custom settings in connection string using "…

…set_" prefix #40

ClickHouse.Client.Tests/ConnectionTests.cs

@@ -33,6 +33,21 @@ public void ShouldThrowExceptionOnInvalidHttpClient()
             Assert.Throws<InvalidOperationException>(() => connection.Open());
         }
 
+        [Test]
+        public void ShouldParseCustomParameter()
+        {
+            using var connection = new ClickHouseConnection("set_my_parameter=aaa");
+            Assert.AreEqual("aaa", connection.CustomSettings["my_parameter"]);
+        }
+
+        [Test]
+        public void ShouldEmitCustomParameter()
+        {
+            using var connection = new ClickHouseConnection();
+            connection.CustomSettings.Add("my_parameter", "aaa");
+            Assert.That(connection.ConnectionString, Contains.Substring("set_my_parameter=aaa"));
+        }
+
         [Test]
         public void ShouldConnectToServer()
         {

ClickHouse.Client/ADO/ClickHouseConnection.cs

@@ -4,6 +4,7 @@
 using System.Data;
 using System.Data.Common;
 using System.IO;
+using System.Linq;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
@@ -18,6 +19,8 @@ namespace ClickHouse.Client.ADO
 {
     public class ClickHouseConnection : DbConnection, IClickHouseConnection, ICloneable
     {
+        private const string CustomSettingPrefix = "set_";
+
         private readonly HttpClient httpClient;
         private readonly ConcurrentDictionary<string, object> customSettings = new ConcurrentDictionary<string, object>();
         private ConnectionState state = ConnectionState.Closed; // Not an autoproperty because of interface implementation
@@ -77,6 +80,10 @@ public sealed override string ConnectionString
                     UseSession = session != null,
                     Timeout = timeout,
                 };
+
+                foreach (var kvp in CustomSettings)
+                    builder[CustomSettingPrefix + kvp.Key] = kvp.Value;
+
                 return builder.ToString();
             }
 
@@ -90,6 +97,11 @@ public sealed override string ConnectionString
                 useCompression = builder.Compression;
                 session = builder.UseSession ? builder.SessionId ?? Guid.NewGuid().ToString() : null;
                 timeout = builder.Timeout;
+
+                foreach (var key in builder.Keys.Cast<string>().Where(k => k.StartsWith(CustomSettingPrefix)))
+                {
+                    CustomSettings.Set(key.Replace(CustomSettingPrefix, string.Empty), builder[key]);
+                }
             }
         }
 

ClickHouse.Client/Utility/DictionaryExtensions.cs

@@ -11,5 +11,13 @@ public static bool TryAdd<TKey, TValue>(this IDictionary<TKey, TValue> dictionar
             dictionary.Add(key, value);
             return true;
         }
+
+        public static void Set<TKey, TValue>(this IDictionary<TKey, TValue> dictionary, TKey key, TValue value)
+        {
+            if (dictionary.ContainsKey(key))
+                dictionary[key] = value;
+            else
+                dictionary.Add(key, value);
+        }
     }
 }