/// <summary>
/// Processes and writes the CSV or Fixed format.
/// </summary>
/// <returns>CSV or Fixed file</returns>
private byte[] WriteCsvToMemory(IEnumerable <StationData> records, string[] columns, DownloadFormatEnum downloadFormat)
{
// Use the streams and writers to generate the file
using (var memoryStream = new MemoryStream())
using (var streamWriter = new StreamWriter(memoryStream))
using (var csvWriter = new CsvWriter(streamWriter))
{
// Remove delimeter for fixed format
// Remove header row for fixed format
if (downloadFormat == DownloadFormatEnum.Fixed)
{
csvWriter.Configuration.Delimiter = "";
csvWriter.Configuration.TrimOptions = CsvHelper.Configuration.TrimOptions.None;
csvWriter.Configuration.ShouldQuote = (field, context) => false;
csvWriter.Configuration.HasHeaderRecord = false;
}
// Configure the columns to write to the file
var map = new CsvHelper.Configuration.DefaultClassMap <StationData>();
foreach (var column in columns)
{
var property = typeof(StationData).GetProperty(column.Replace("_", ""));
// Use the FixedWidthConverter for the fixed format
if (downloadFormat == DownloadFormatEnum.Fixed)
{
map.Map(typeof(StationData), property).TypeConverter <FixedWidthConverter>();
}
else
{
map.Map(typeof(StationData), property);
}
}
csvWriter.Configuration.RegisterClassMap(map);
// Write the records and flush
csvWriter.WriteRecords(records);
streamWriter.Flush();
return(memoryStream.ToArray());
}
}
public async Task <IActionResult> MeteorologicalDownload(int id, DateTime beginDate, DateTime endDate, DownloadFormatEnum downloadFormat, string variables)
{
// Validation:
// 1. Must have 1 variable selected
// 2. endDate must come after beginDate
// 3. Timespan between beginDate and endDate must be 31 or less days
if (variables == null || beginDate > endDate || (endDate - beginDate).Days > 31)
{
return(View("Error", new ErrorDto {
StatusCode = 400
}));
}
// Get station Info
var stationInfo = await _stationService.GetStationInfo(id);
// Get data for the file
var data = await _stationDataService.MeteorologicalDownloadData(id, beginDate, endDate);
// File extension
var extension = "csv";
if (downloadFormat == DownloadFormatEnum.Fixed)
{
extension = "dat";
}
// Add Timestamp column for CSV
if (downloadFormat == DownloadFormatEnum.CSV)
{
variables = "Ts," + variables;
}
// Create file name
var fileName = stationInfo.DisplayName.Replace(" ", "_")
+ "_" + beginDate.ToString(Constant.DATE_FILE_FORMAT)
+ "_" + endDate.ToString(Constant.DATE_FILE_FORMAT)
+ "." + extension;
// Create the memory stream for the file
var memoryStream = new MemoryStream(WriteCsvToMemory(data, variables.Split(","), downloadFormat));
// Return the file stream
return(new FileStreamResult(memoryStream, "text/csv")
{
FileDownloadName = fileName
});
}
