Ninject, DapperWrapper injecting SqlExecutor - ninject

Question

I am trying to create some "repository" style classes to wrap calls to Dapper via DapperWrapper. Trying to inject SqlExecutor into the repository checking for an attribute to determine which database to connect to.
Here is the repository implementation so you can see what I am trying to do:
public class ProviderRepository : IProviderRepository<SearchType>
{
private readonly IDbExecutor executor;
public ProviderRepository([BHN]IDbExecutor executor)
{
this.executor = executor;
}
public IList<SearchType> GetAllSearchTypes()
{
return executor
.Query<SearchType>("BHN.pSEL_LU_SEARCHTYPE_Load", commandType: CommandType.StoredProcedure)
.ToList();
}
}
And here is my ninject binding which I know is bad but just to illustrate what I am trying to do:
kernel.Bind<IDbExecutor>().To<SqlExecutor>()
.WhenTargetHas<BHNAttribute>()
.WithConstructorArgument("sqlConnection",
new SqlConnection(connections["ProviderSearch"].ConnectionString));
Note: BHNAttribute is just an empty class inheriting from Attribute.
Now obviously problem with this is that the sql connection is created on app start, which I understand, but how can I make that load when it is used instead of at application load? Ive been toying around the Ninject Factory extension, but I am having trouble with what that implementation might look like. So I created this:
public class ExecutorFactory
{
private ISqlExecutorFactory executor;
public ExecutorFactory(ISqlExecutorFactory executor)
{
this.executor = executor;
}
public void Do()
{
var e = this.executor.CreateSqlExecutor("string");
}
}
public interface ISqlExecutorFactory
{
SqlExecutor CreateSqlExecutor(string conn);
}
And my binding would look like this:
kernel.Bind<ISqlExecutorFactory>.ToFactory();
The "string" in the factory class would would be "ProviderSearch" and need to be passed to the ToFactory() method I assuming, but I dont understand how I would do that and incorporate the use of the BHNAttribute, like I was doing before. Or if that's even possible at this point.
Am I looking at this the wrong way?

Answer 1

So I figured this one out on my own... interesting solution here so I thought I would share it for the world. I ended up using a provider (ToProvider)
My provider implementation:
public class ExecutorProvider : Provider<IDbExecutor>
{
private readonly string _connectoinString;
public ExecutorProvider(Func<string> connectionString)
{
_connectionString = connectionString();
}
protected override IDbExecutor CreateInstance(IContext context)
{
return new SqlExecutor(() => {
var sqlconnection = new SqlConnection(_connectionString);
sqlconnection.Open();
return sqlconnection;
});
}
}
Then I created a new implementation of the SqlExecutor using Lazy(T) to only instantiate and open SqlConnection when it is used:
public class SqlExecutor : IDbExecutor
{
readonly Lazy<SqlConnection> _sqlConnection;
public SqlExecutor(Func<SqlConnection> sqlConnection)
{
_sqlConnection = new Lazy<SqlConnection>(() => sqlConnection());
}
public int Execute(
string sql,
object param = null,
IDbTransaction transaction = null,
int? commandTimeout = default(int?),
CommandType? commandType = default(CommandType?))
{
return _sqlConnection.Value.Execute(
sql,
param,
transaction,
commandTimeout,
commandType);
}
public IEnumerable<dynamic> Query(
string sql,
object param = null,
IDbTransaction transaction = null,
bool buffered = true,
int? commandTimeout = default(int?),
CommandType? commandType = default(CommandType?))
{
return _sqlConnection.Value.Query(
sql,
param,
transaction,
buffered,
commandTimeout,
commandType);
}
public IEnumerable<T> Query<T>(
string sql,
object param = null,
IDbTransaction transaction = null,
bool buffered = true,
int? commandTimeout = default(int?),
CommandType? commandType = default(CommandType?))
{
return _sqlConnection.Value.Query<T>(
sql,
param,
transaction,
buffered,
commandTimeout,
commandType);
}
public void Dispose()
{
_sqlConnection.Value.Dispose();
}
}
And then my binding:
kernel.Bind<IDbExecutor>().ToProvider(new ExecutorProvider(()
=> connections["ProviderSearch"].ConnectionString))
.WhenTargetHas<BHNAttribute>()
.InRequestScope();
This allows me to do this during injection on my implementing classes to associate injected sql executors with a database connection based on the attribute:
public class ProviderRepository : IProviderRepository
{
private readonly IDbExecutor executor;
public ProviderRepository([BHN]IDbExecutor executor)
{
this.executor = executor;
}
public IList<SearchType> GetAllSearchTypes()
{
return executor
.Query<SearchType>("pSEL_LU_SEARCHTYPE_Load", commandType: CommandType.StoredProcedure)
.ToList();
}
}
BHNAttribute([BHN]) is just an empty class inheriting from Attribute.
NOTE: Yes I know using stored procs for this is lame, but my hands are tied on that one unfortunately.
I dont like having to re-create the SqlExecutor class, but this works really well.