public async Task CsvHelperAsync()
{
TextWriter tw = TextWriter.Null;
var items = TestData.GetTestObjects();
var csv = new CsvHelper.CsvWriter(tw, new CsvConfiguration(CultureInfo.InvariantCulture));
csv.WriteField("Id");
csv.WriteField("Name");
csv.WriteField("Date");
csv.WriteField("IsActive");
for (int i = 0; i < ValueCount; i++)
{
csv.WriteField("Value" + i);
}
await csv.NextRecordAsync();
foreach (var item in items)
{
csv.WriteField(item.Id);
csv.WriteField(item.Name);
csv.WriteField(item.Date);
csv.WriteField(item.IsActive);
for (int i = 0; i < ValueCount; i++)
{
csv.WriteField(item.DataSet[i]);
}
await csv.NextRecordAsync();
}
await csv.FlushAsync();
}
public async Task <byte[]> ToCsvAsync()
{
using var memoryStream = new System.IO.MemoryStream();
using var writer = new System.IO.StreamWriter(memoryStream);
using var csv = new CsvHelper.CsvWriter(writer,
new CsvConfiguration(CultureInfo.InvariantCulture));
await csv
.WriteRecordsAsync(await _schoolService.GetForExportAsync());
await csv.FlushAsync();
await writer.FlushAsync();
await memoryStream.FlushAsync();
return(memoryStream.ToArray());
}
public async Task <byte[]> ToCsvAsync()
{
var branches = await _siteService.GetAllBranches();
using var memoryStream = new System.IO.MemoryStream();
using var writer = new System.IO.StreamWriter(memoryStream);
using var csv = new CsvHelper.CsvWriter(writer,
new CsvConfiguration(CultureInfo.InvariantCulture));
csv.Context.RegisterClassMap <Maps.BranchMap>();
await csv.WriteRecordsAsync(branches.OrderBy(_ => _.SystemName).ThenBy(_ => _.Name));
await csv.FlushAsync();
await writer.FlushAsync();
await memoryStream.FlushAsync();
return(memoryStream.ToArray());
}
/// <summary>
/// Uploads book cover images to ipfs
/// Writes a mapping csv file to relate ean, image size, ipfs hash etc
/// Assumes the book cover images are held locally so....
/// Ensure the cover images have been downloaded first! (DownloadCoversAsync)
/// </summary>
/// <param name="books"></param>
/// <returns></returns>
public static async Task UploadCoversToIpfsAsync(
IEnumerable <Book> books, string coverFolder, string indexOutputFilePath, string ipfsUrl)
{
ipfsFilesLoaded = 0;
//indexOutputFilePath
try
{
// we'll parallel load images - but don't want to write to the csv in parallel
var semaphore = new SemaphoreSlim(1);
using (var textWriter = File.CreateText(indexOutputFilePath))
{
var csvWriter = new CsvHelper.CsvWriter(textWriter, CultureInfo.InvariantCulture);
csvWriter.WriteHeader <IpfsBookCoverMapping>();
csvWriter.NextRecord();
try
{
var ipfsService = new IpfsService(ipfsUrl);
foreach (var book in books.AsParallel())
{
if (!string.IsNullOrWhiteSpace(book.COVER_SMALL))
{
var smallCover = await UploadCoverToIpfs(coverFolder, book.EAN, "s", book.COVER_SMALL, ipfsService);
await Save(smallCover);
}
if (!string.IsNullOrWhiteSpace(book.COVER_MED))
{
var mediumCover = await UploadCoverToIpfs(coverFolder, book.EAN, "m", book.COVER_MED, ipfsService);
await Save(mediumCover);
}
if (!string.IsNullOrWhiteSpace(book.COVER_LARGE))
{
var largeCover = await UploadCoverToIpfs(coverFolder, book.EAN, "l", book.COVER_LARGE, ipfsService);
await Save(largeCover);
}
async Task Save(IpfsBookCoverMapping mapping)
{
await semaphore.WaitAsync();
try
{
csvWriter.WriteRecord(mapping);
csvWriter.NextRecord();
}
finally
{
semaphore.Release();
}
}
}
}
finally
{
await csvWriter.FlushAsync();
await textWriter.FlushAsync();
}
}
}
finally
{
// consider changing file name on completion to avoid it being overwritten accidentally
}
}