internal async Task Init(string copyFromCommand, bool async, CancellationToken cancellationToken = default)
{
await _connector.WriteQuery(copyFromCommand, async, cancellationToken);
await _connector.Flush(async, cancellationToken);
using var registration = _connector.StartNestedCancellableOperation(cancellationToken, attemptPgCancellation: false);
CopyInResponseMessage copyInResponse;
var msg = await _connector.ReadMessage(async);
switch (msg.Code)
{
case BackendMessageCode.CopyInResponse:
copyInResponse = (CopyInResponseMessage)msg;
if (!copyInResponse.IsBinary)
{
throw _connector.Break(
new ArgumentException("copyFromCommand triggered a text transfer, only binary is allowed",
nameof(copyFromCommand)));
}
break;
case BackendMessageCode.CommandComplete:
throw new InvalidOperationException(
"This API only supports import/export from the client, i.e. COPY commands containing TO/FROM STDIN. " +
"To import/export with files on your PostgreSQL machine, simply execute the command with ExecuteNonQuery. " +
"Note that your data has been successfully imported/exported.");
default:
throw _connector.UnexpectedMessageReceived(msg.Code);
}
NumColumns = copyInResponse.NumColumns;
_params = new NpgsqlParameter[NumColumns];
_rowsImported = 0;
_buf.StartCopyMode();
WriteHeader();
}