/// <summary>
/// Connect to a stream of flat file data
/// </summary>
/// <param name="stream">The stream of data to connect to</param>
/// <returns>If the data was valid and is a stream</returns>
public override Boolean Connect(DataItemDefinition definition, DataConnection connection, Stream stream)
{
this.Connection = connection;
this.definition = definition; // Assign the definition to use
this.memoryData = new DataTable(); // Blank data by default
// Do we have a stream and a definition
if (stream != null && definition == null)
{
base.connected = true;
return(true);
}
else if (stream != null && definition != null)
{
stream.Position = 0; // Reset back to the start again in case someone else has read it
base.MarkLastAction(); // Tell the provider base class that it did something
// Read the data from the stream provided
using (StreamReader textReader = new StreamReader(stream))
{
this.memoryData = DelimitedFileHelper.TextToDataTable(definition, connection, textReader.ReadToEnd());
base.connected = true; // Mark the provider as connected
return(true); // Connected without any errors
}
}
return(false); // Failed if we get to here
}
/// <summary>
/// Connect to the flat file source
/// </summary>
/// <param name="connectionString">The connection string to use</param>
/// <returns>If the file exists when it is connected</returns>
public override Boolean Connect(DataItemDefinition definition, DataConnection connection)
{
Boolean result = false; // Failed by default
// Check if not an object
if (connection == null)
{
return(false);
}
// Get the processed connection string (with any injected items)
String connectionString = connection.ConnectionStringProcessed;
// Does the file that we are trying to connect to exist?
if (File.Exists(connectionString))
{
// Connect to the file and read the data from it
using (Stream fileStream = File.OpenRead(connectionString))
{
result = Connect(definition, connection, fileStream); // Do a standard stream connect to reuse that code
if (result)
{
this.Connection = connection; // Remember the connection string
}
}
}
this.MarkLastAction(); // Tell the provider base class that it did something
return(result); // Return the result of the read
}
/// <summary>
/// Analyse the connection to get the definition back
/// </summary>
/// <param name="request">The analysis request paramaters</param>
/// <returns>The data item definition derived from the connection and object</returns>
public override DataItemDefinition Analyse(AnalyseRequest <object> request)
{
DataItemDefinition result = new DataItemDefinition(); // Empty Response By Default
// Are we connected and have an object name?
if ((this.ObjectName ?? String.Empty) != String.Empty &&
this.Connected)
{
// Set up the command to run and select all columns from the object
using (SqlCommand command =
new SqlCommand($"select top {request.SampleSize.ToString()} * from {this.ObjectName}", this.sqlConnection))
{
// Run the command
using (SqlDataReader dataReader = command.ExecuteReader())
{
DataTable tempTable = new DataTable(); // Create a temporary table
tempTable.Load(dataReader); // Run the data reader to load the results
result.FromDataTable(tempTable); // Tell the definition to load itself from the data table provided
// Clean up
tempTable = null;
}
}
}
// Send the result back
return(result);
}
public IDataProvider Get(
Package package,
DataConnection connection,
DataItemDefinition definition,
Boolean addToCache)
{
IDataProvider result = null; // Create a fail state by default
// Do we already have a provider set up for this data connection
String uniqueKey = GenerateConnectionKey(
new List <Guid>()
{
connection.Id,
((definition == null || definition.Id == null) ? Guid.Empty : definition.Id)
});
Boolean existingProvider = providers.ContainsKey(uniqueKey);
if (!existingProvider)
{
result = Get(connection.ProviderType);
}
else
{
result = providers[uniqueKey];
}
// If the provider is stale (something configuration-wise has been changed)
if (result?.LastAction <= connection.LastUpdated)
{
#warning "Need a simple way of reseting a connection rather than doing each change manually"
}
// Did we get a provider?
if (result != null)
{
// Set the package if it is not assigned
connection.ParentPackage = (connection.ParentPackage ?? package);
// Set the provider to be connected if it is not already connected
// or if the provider has an updated definition
if (!result.Connected || (definition != null && result.LastAction <= definition.LastUpdated))
{
result.Connect(definition, connection); // Connect attempt
existingProvider = false; // Re-connected potentially so reset to make sure it's added to the cache
}
// If the provider was not in the pooled collection of providers then add it
if (!existingProvider && addToCache)
{
providers[uniqueKey] = result;
}
}
// Return the provider
return(result);
}
/// <summary>
/// Look at the file and try and represent the file as a dataset without a definition
/// </summary>
/// <returns>A representation of the data</returns>
public override DataItemDefinition Analyse(AnalyseRequest <Object> request)
{
// Create a blank result data table
DataItemDefinition result = new DataItemDefinition()
{
};
String rawData = ""; // The data which ultimately will be read from
// Check to see what can of analysis is being requested
if ((request.Connection?.ConnectionString ?? String.Empty) != String.Empty)
{
// Get the stream of data from the raw file
rawData = File.ReadAllText(request.Connection.ConnectionStringProcessed);
}
else
{
// No connection was provided so use the raw data provided instead
switch (request.Data.GetType().ToShortName())
{
case "string":
rawData = (String)request.Data;
break;
default:
((Stream)request.Data).Position = 0; // Reset the stream position
// Read the data from the stream
StreamReader reader = new StreamReader((Stream)request.Data);
rawData = reader.ReadToEnd();
// Reset the position again so that it can be re-used
((Stream)request.Data).Position = 0;
break;
}
}
// Pass down to the analyse text core function
AnalyseRequest <String> analyseTextRequest =
new AnalyseRequest <String>()
{
Data = rawData,
Connection = request.Connection
};
result = DelimitedFileHelper.AnalyseText(analyseTextRequest);
base.MarkLastAction(); // Tell the provider base class that it did something
// Send the analysis data table back
return(result);
}
/// <summary>
/// Override the connection object to connect to the Sql Server
/// </summary>
/// <param name="definition">The definition of the data to connect to</param>
/// <param name="connection">The connect properties to connect to the server</param>
/// <returns>If the connection worked</returns>
public override Boolean Connect(DataItemDefinition definition, DataConnection connection)
{
if (!this.Connected)
{
// Connect to the sql server
this.sqlConnection = new SqlConnection(connection.ConnectionStringProcessed);
try
{
this.sqlConnection.Open(); // Start the connection
this.definition = definition; // Assign the definition
this.ObjectName = connection.ObjectName; // Assign the object name being set to
return(true); // Success!
}
catch (Exception ex)
{
return(false);
}
}
else
{
return(true); // Already connected, why return false?
}
}
/// <summary> /// Connect to this connection /// </summary> /// <param name="definition">The definition of the data in the connection</param> /// <param name="connection">The connection</param> /// <param name="stream">The stream to connect to</param> /// <returns>If the system connected ok</returns> public virtual bool Connect(DataItemDefinition definition, DataConnection connection, Stream stream) => throw new NotImplementedException();
