Move dotnet api into new directory

web/backend/Infrastructure/Infrastructure.Repository/Sql/SqlConnectionStringHelper.cs

@@ -0,0 +1,61 @@
+using Microsoft.Data.SqlClient;
+
+namespace Infrastructure.Repository.Sql;
+
+public static class SqlConnectionStringHelper
+{
+    /// <summary>
+    /// Builds a SQL Server connection string from environment variables.
+    /// Expects DB_SERVER, DB_NAME, DB_USER, DB_PASSWORD, and DB_TRUST_SERVER_CERTIFICATE.
+    /// </summary>
+    /// <param name="databaseName">Optional override for the database name. If null, uses DB_NAME env var.</param>
+    /// <returns>A properly formatted SQL Server connection string.</returns>
+    public static string BuildConnectionString(string? databaseName = null)
+    {
+        var server =
+            Environment.GetEnvironmentVariable("DB_SERVER")
+            ?? throw new InvalidOperationException(
+                "DB_SERVER environment variable is not set"
+            );
+
+        var dbName =
+            databaseName
+            ?? Environment.GetEnvironmentVariable("DB_NAME")
+            ?? throw new InvalidOperationException(
+                "DB_NAME environment variable is not set"
+            );
+
+        var user =
+            Environment.GetEnvironmentVariable("DB_USER")
+            ?? throw new InvalidOperationException(
+                "DB_USER environment variable is not set"
+            );
+
+        var password =
+            Environment.GetEnvironmentVariable("DB_PASSWORD")
+            ?? throw new InvalidOperationException(
+                "DB_PASSWORD environment variable is not set"
+            );
+
+        var builder = new SqlConnectionStringBuilder
+        {
+            DataSource = server,
+            InitialCatalog = dbName,
+            UserID = user,
+            Password = password,
+            TrustServerCertificate = true,
+            Encrypt = true,
+        };
+
+        return builder.ConnectionString;
+    }
+
+    /// <summary>
+    /// Builds a connection string to the master database using environment variables.
+    /// </summary>
+    /// <returns>A connection string for the master database.</returns>
+    public static string BuildMasterConnectionString()
+    {
+        return BuildConnectionString("master");
+    }
+}