public static async Task <byte[]> AggregatePdfsAsync(this IEnumerableAsync <byte[]> pdfs)
{
var composedPdf = await pdfs.AggregateAsync(
new PdfDocument(),
(outputPdf, pdfBytes) =>
{
if (pdfBytes.IsDefaultNullOrEmpty())
{
return(outputPdf);
}
var stream = new MemoryStream(pdfBytes);
var doc = PdfReader.Open(stream, PdfDocumentOpenMode.Import);
foreach (var page in doc.Pages)
{
outputPdf.AddPage(page);
}
return(outputPdf);
});
var concatenatedStream = new MemoryStream();
composedPdf.Save(concatenatedStream);
return(await concatenatedStream.ToBytesAsync());
}