Stream to read the data into during this download operation.
public Stream Stream {get; set;}
Stream into which to read the document data. The default value is null.
To download a document from the cache, use either Data or Stream, but not both. In other words, one of these properties must be set to a non-null value to indicate the target for the download operation.
When Stream is used, the data is stored beginning at the offset stored in the stream itself, and DataOffset is not used.
DataOffset is the 0-based byte offset into the source data at which to begin reading the data.
Length is the maximum number of bytes to read.
using Leadtools;
using Leadtools.Codecs;
using Leadtools.Document.Writer;
using Leadtools.Document;
using Leadtools.Caching;
using Leadtools.Annotations.Engine;
using Leadtools.Ocr;
using Leadtools.Barcode;
using Leadtools.Document.Converter;
public void DownloadDocumentExample()
{
var documentUri = new Uri("https://demo.leadtools.com/images/pdf/leadtools.pdf");
string documentFile1 = Path.Combine(LEAD_VARS.ImagesDir, "downloaded1.pdf");
string documentFile2 = Path.Combine(LEAD_VARS.ImagesDir, "downloaded2.pdf");
// Setup a cache
FileCache cache = new FileCache();
cache.CacheDirectory = @"c:\cache-dir";
string documentId;
// Load a document into the cache
var loadDocumentOptions = new LoadDocumentOptions();
loadDocumentOptions.Cache = cache;
using (var document = DocumentFactory.LoadFromUri(documentUri, loadDocumentOptions))
{
// Get its document ID and save it
documentId = document.DocumentId;
document.AutoDeleteFromCache = false;
document.AutoSaveToCache = false;
document.SaveToCache();
}
// Now download it all at once into a memory stream
var downloadDocumentOptions = new DownloadDocumentOptions();
downloadDocumentOptions.Cache = cache;
downloadDocumentOptions.DocumentId = documentId;
downloadDocumentOptions.Offset = 0;
downloadDocumentOptions.Length = -1;
using (var stream = new MemoryStream())
{
downloadDocumentOptions.Stream = stream;
long bytes = DocumentFactory.DownloadDocument(downloadDocumentOptions);
Console.WriteLine("Downloaded {0} bytes into the stream", bytes);
long annotations = DocumentFactory.DownloadAnnotations(downloadDocumentOptions);
Console.WriteLine(annotations + " annotations downloaded");
// The following method is obsolete. Use DownloadAnnotations(DownloadDocumentOptions) instead
int annotations2 = DocumentFactory.DownloadAnnotations(downloadDocumentOptions.Cache, downloadDocumentOptions.DocumentId, downloadDocumentOptions.Offset, (int)bytes, stream);
Console.WriteLine(annotations2 + " annotations downloaded");
// Save the stream to a file and show it
using (var output = File.Create(documentFile1))
stream.WriteTo(output);
Process.Start(documentFile1);
}
// Download it again, this time we will buffer it 32K at a time
downloadDocumentOptions = new DownloadDocumentOptions();
downloadDocumentOptions.Cache = cache;
downloadDocumentOptions.DocumentId = documentId;
byte[] buffer = new byte[1024 * 32];
using (var output = File.Create(documentFile2))
{
// Offset to where we are:
long offset = 0;
int bytes;
do
{
downloadDocumentOptions.Offset = offset;
downloadDocumentOptions.Length = buffer.Length;
downloadDocumentOptions.Data = buffer;
downloadDocumentOptions.DataOffset = 0;
bytes = (int)DocumentFactory.DownloadDocument(downloadDocumentOptions);
if (bytes > 0)
{
Console.WriteLine("Downloaded {0} bytes into the buffer", bytes);
// Next chunk
offset += bytes;
output.Write(buffer, 0, bytes);
// The following method is obsolete. Use DownloadAnnotations(DownloadDocumentOptions) instead
int annotations = DocumentFactory.DownloadAnnotations(downloadDocumentOptions.Cache, downloadDocumentOptions.DocumentId, downloadDocumentOptions.Offset, buffer, downloadDocumentOptions.DataOffset, buffer.Length);
Console.WriteLine(annotations + " annotations downloaded");
}
}
while (bytes > 0);
}
Process.Start(documentFile2);
// We are done, clean up
var deleteFromCacheOptions = new LoadFromCacheOptions();
deleteFromCacheOptions.Cache = cache;
deleteFromCacheOptions.DocumentId = documentId;
DocumentFactory.DeleteFromCache(deleteFromCacheOptions);
}
static class LEAD_VARS
{
public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images";
}