It will break
With no error handling the code was a bit fragile so I modified the program.cs file and added support for the built in logging and Debug provider. To reduce the amount of code in the controller I have also moved the DTO to a separate file in the “models” folder.
namespace devMobile.WebAPIDapper.Lists
{
public class Program
{
public static void Main(string[] args)
{
CreateHostBuilder(args).Build().Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureLogging(logging =>
{
logging.ClearProviders();
logging.AddDebug();
})
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseStartup<Startup>();
});
}
}
To test the exception handling I “broke” the Dapper query embedded SQL.
namespace devMobile.WebAPIDapper.Lists.Controllers
{
[Route("api/[controller]")]
[ApiController]
public class StockItemsFailureController: ControllerBase
{
private readonly string connectionString;
private readonly ILogger<StockItemsFailureController> logger;
public StockItemsFailureController(IConfiguration configuration, ILogger<StockItemsFailureController> logger)
{
this.connectionString = configuration.GetSection("ConnectionStrings").GetSection("WideWorldImportersDatabase").Value;
this.logger = logger;
}
[HttpGet]
public ActionResult<IEnumerable<Model.StockItemListDtoV1>> Get()
{
IEnumerable<Model.StockItemListDtoV1> response = null;
try
{
using (SqlConnection db = new SqlConnection(this.connectionString))
{
response = db.Query<Model.StockItemListDtoV1>(sql: @"SELECTx [StockItemID] as ""ID"", [StockItemName] as ""Name"", [RecommendedRetailPrice], [TaxRate] FROM [Warehouse].[StockItems]", commandType: CommandType.Text);
}
}
catch( SqlException ex)
{
logger.LogError(ex, "Retrieving list of StockItems");
return this.StatusCode(StatusCodes.Status500InternalServerError);
}
return this.Ok(response);
}
}
The controller failed and the following error was displayed in the Visual Studio output window
devMobile.WebAPIDapper.Lists.Controllers.StockItemsFailureController: Error: Retrieving list of StockItems
System.Data.SqlClient.SqlException (0x80131904): Incorrect syntax near the keyword 'as'.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
at System.Data.SqlClient.SqlDataReader.TryConsumeMetaData()
at System.Data.SqlClient.SqlDataReader.get_MetaData()
at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite, String method)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior)
at Dapper.SqlMapper.ExecuteReaderWithFlagsFallback(IDbCommand cmd, Boolean wasClosed, CommandBehavior behavior) in /_/Dapper/SqlMapper.cs:line 1055
at Dapper.SqlMapper.QueryImpl[T](IDbConnection cnn, CommandDefinition command, Type effectiveType)+MoveNext() in /_/Dapper/SqlMapper.cs:line 1083
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at Dapper.SqlMapper.Query[T](IDbConnection cnn, String sql, Object param, IDbTransaction transaction, Boolean buffered, Nullable`1 commandTimeout, Nullable`1 commandType) in /_/Dapper/SqlMapper.cs:line 725
at devMobile.WebAPIDapper.Lists.Controllers.StockItemsFailureController.Get() in C:\Users\BrynLewis\source\repos\WebAPIDapper\Lists\Controllers\03.StockItemsFailureController.cs:line 53
ClientConnectionId:f37eb089-a560-406d-8c24-cf904bb17d8a
Error Number:156,State:1,Class:15
The program '[16996] iisexpress.exe: Program Trace' has exited with code 0 (0x0).
The program '[16996] iisexpress.exe' has exited with code -1 (0xffffffff).
In a couple of future posts I will add support for Log4Net, nLog, Serilog and a couple other libraries.
