11-interceptação.md

Interceptação

• 1 - O que são interceptadores de comandos?
• 2 - Criando e registrando um interceptador
• 3 - Sobrescrevendo métodos da classe base
• 4 - Aplicando hint NOLOCK nas consultas
• 5 - Interceptando abertura de conexão com o banco
• 6 - Interceptando alterações.

1 - O que são interceptadores de comandos?

Três interfaces importantes para esse recurso: * IDbCommandInterceptor * IDbConnectionInterceptor * IDbTransactionInterceptor

2 - Criando e registrando um interceptador

public class InterceptadorDeComandos : DbCommandInterceptor
{    
}

// Definindo um interceptador


//OnConfiguring
optionsBuilder
    .UseSqlServer(stringDeConexao)
    .EnableSensitiveDataLogging()
    .LogTo(Console.WriteLine, LogLevel.Information)
    .AddInterceptors(new InterceptadorDeComandos())

3 - Sobrescrevendo métodos da classe base

Docs oficial sobre interceptação

4 - Aplicando hint NOLOCK nas consultas

Um exemplo pratico

private static readonly Regex _tableRegex =
   new Regex(@"(?<tableAlias>FROM +(\[.*\]\.)?(\[.*\]) AS (\[.*\])(?! WITH \(NOLOCK\)))", 
       RegexOptions.Multiline | 
       RegexOptions.IgnoreCase | 
       RegexOptions.Compiled);

public override InterceptionResult<DbDataReader> ReaderExecuting(
   DbCommand command,
   CommandEventData eventData,
   InterceptionResult<DbDataReader> result)
{
   Console.WriteLine("[Sync] Entrei dentro do metodo ReaderExecutings");
   UsarNoLock(command);

   return base.ReaderExecuting(command, eventData, result);
}

private static void UsarNoLock(DbCommand command)
{
   if (command.CommandText.Contains("WITH (NOLOCK)"))
       return;

   command.CommandText = _tableRegex
       .Replace(command.CommandText, "${tableAlias} WITH (NOLOCK)");
}

5 - Interceptando abertura de conexão com o banco

optionsBuilder
    .UseSqlServer(stringDeConexao)
    .EnableSensitiveDataLogging()
    .LogTo(Console.WriteLine, LogLevel.Information)
    .AddInterceptors(new InterceptadorDeComandos())
    .AddInterceptors(new InterceptadorDeConexao())
    ;



public class InterceptadorDeConexao : DbConnectionInterceptor
{
    public override InterceptionResult ConnectionOpening(
        DbConnection connection, 
        ConnectionEventData eventData, 
        InterceptionResult result)
    {

        Console.WriteLine("Entrei no metodo ConnectionOpening");

        Console.WriteLine(connection.ConnectionString);

        var builder = new SqlConnectionStringBuilder(connection.ConnectionString)
        {
            ApplicationName = "Rider CursoEFCore"
        };

        connection.ConnectionString = builder.ToString();
        Console.WriteLine(builder.ToString());
        
        return result;
    }
}

6 - Interceptando alterações.

optionsBuilder
    .UseSqlServer(stringDeConexao)
    .EnableSensitiveDataLogging()
    .LogTo(Console.WriteLine, LogLevel.Information)
    .AddInterceptors(new InterceptadorDeComandos())
    .AddInterceptors(new InterceptadorDeConexao())
    .AddInterceptors(new InterceptadorDePercistencia())
    ;


public class InterceptadorDeConexao : DbConnectionInterceptor
{
    public override InterceptionResult ConnectionOpening(
        DbConnection connection, 
        ConnectionEventData eventData, 
        InterceptionResult result)
    {

        Console.WriteLine("Entrei no metodo ConnectionOpening");

        Console.WriteLine(connection.ConnectionString);

        var builder = new SqlConnectionStringBuilder(connection.ConnectionString)
        {
            ApplicationName = "Rider CursoEFCore"
        };

        connection.ConnectionString = builder.ToString();
        Console.WriteLine(builder.ToString());
        
        return result;
    }
}