private async Task <(IReadOnlyList <string> Names, IReadOnlyList <string> DetectedTypes)> GetSourceColumns()
{
var tempTableName = Guid.NewGuid().ToString();
try {
var headerRow = _optionsControl.HasColumnHeaders.Value;
var fileEncoding = _optionsControl.FileEncoding.Value;
var skipLines = _optionsControl.SkipLines.Value;
var separator = _optionsControl.Separator.Value;
return(await Task.Run(() => {
var importSql =
@$ "IMPORT CSV @filePath INTO @tableName
OPTIONS (SKIP_LINES: @skipLines, TAKE_LINES: 1000, HEADER_ROW: @headerRow, TEMPORARY_TABLE: 1,
FILE_ENCODING: @encoding, SEPARATOR: @sep);
SELECT * FROM {SqlUtil.DoubleQuote(tempTableName)};";
var output = _manager.ExecuteScript(importSql, new Dictionary <string, object> {
["@filePath"] = _filePath,
["@tableName"] = tempTableName,
["@sep"] = separator,
["@headerRow"] = headerRow ? 1 : 0,
["@encoding"] = fileEncoding,
["@skipLines"] = skipLines
});
IReadOnlyList <string> detectedTypes = null;
try {
detectedTypes = TypeDetection.DetectTypes(output.DataTables[0]);
} catch {
// Don't let this blow up the import.
detectedTypes = Array.Empty <string>();
}
using var dt = _manager.ExecuteScript($"PRAGMA TABLE_INFO ({tempTableName.DoubleQuote()})")
.DataTables[0];
var nameCol = dt.GetIndex("name");
return (dt.Rows.Select(x => x[nameCol].ToString()).Where(x => !string.IsNullOrEmpty(x)).ToList(), detectedTypes);
}));
} finally {
await Task.Run(() => {
_manager.ExecuteScriptNoOutput($"DROP TABLE IF EXISTS {tempTableName.DoubleQuote()}");
});
}
}