DownloadDocument(ObjectCache,Uri,long,int,Stream) Method

Summary

Downloads the data of the specified document URI into a stream.

Syntax

C++/CLI

Python

[ObsoleteAttribute("User DownloadDocument(DownloadDocumentOptions) instead")] 
public static int DownloadDocument( 
   ObjectCache cache, 
   Uri uri, 
   long offset, 
   int bytes, 
   Stream stream 
)

public:  
   [ObsoleteAttribute(L"User DownloadDocument(DownloadDocumentOptions) instead")] 
   static Int32 DownloadDocument( 
      ObjectCache^ cache, 
      Uri^ uri, 
      Int64 offset, 
      Int32 bytes, 
      Stream^ stream 
   )

def DownloadDocument(self,cache,uri,offset,bytes,stream):

Parameters

cache

The cache containing the document. This value cannot be null.

uri

The URI of the document to download.

offset

0-based byte offset into the source data at which to begin reading the data.

bytes

The maximum number of bytes to read. If this value is -1, then the remaining data will be read till the end is reached.

stream

Stream to read the data into. This should be a write-able stream and cannot be null.

Return Value

The total number of bytes read into stream. This can be less than the number of bytes requested by bytes if that many bytes are not currently available, or zero (0) if the end of the data has been reached.

Remarks

Similar to UploadDocument, data can be downloaded in chunks or all at once. Refer to Uploading Using the Document Library for detailed information on how to use these methods and the various options used.

GetDocumentCacheInfo can be used to determine if a document is in the cache and to get its information.

DownloadAnnotations can be used to download the annotations of a document (if any).

Example

Java

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:\LEADTOOLS23\Resources\Images"; 
}

 
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.net.MalformedURLException; 
import java.net.URI; 
import java.net.URISyntaxException; 
import java.net.URL; 
import java.nio.file.Files; 
import java.nio.file.Paths; 
import java.util.ArrayList; 
import java.util.Calendar; 
import java.util.List; 
import java.util.concurrent.Callable; 
import java.util.concurrent.ExecutorService; 
import java.util.concurrent.Executors; 
import java.util.concurrent.Future; 
import java.util.regex.Pattern; 
 
import org.junit.*; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
import static org.junit.Assert.*; 
 
import leadtools.*; 
import leadtools.annotations.engine.*; 
import leadtools.barcode.*; 
import leadtools.caching.*; 
import leadtools.codecs.*; 
import leadtools.document.*; 
import leadtools.document.DocumentMimeTypes.UserGetDocumentStatusHandler; 
import leadtools.document.converter.*; 
import leadtools.document.writer.*; 
import leadtools.ocr.*; 
 
 
public void downloadDocumentExample() throws IOException, URISyntaxException { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   URI documentUri = new URI("https://demo.leadtools.com/images/pdf/leadtools.pdf"); 
   String documentFile1 = combine(LEAD_VARS_IMAGES_DIR, "downloaded1.pdf"); 
   String documentFile2 = combine(LEAD_VARS_IMAGES_DIR, "downloaded2.pdf"); 
 
   // Setup a cache 
   FileCache cache = new FileCache(); 
   cache.setCacheDirectory("c:\\cache-dir"); 
 
   String documentId; 
 
   // Load a document into the cache 
   LoadDocumentOptions loadDocumentOptions = new LoadDocumentOptions(); 
   loadDocumentOptions.setCache(cache); 
   LEADDocument document = DocumentFactory.loadFromUri(documentUri, loadDocumentOptions); 
 
   // Get its document ID and save it 
   documentId = document.getDocumentId(); 
   document.setAutoDeleteFromCache(false); 
   document.setAutoSaveToCache(false); 
   document.saveToCache(); 
 
   // Now download it all at once into a memory stream 
   DownloadDocumentOptions downloadDocumentOptions = new DownloadDocumentOptions(); 
   downloadDocumentOptions.setCache(cache); 
   downloadDocumentOptions.setDocumentId(documentId); 
   downloadDocumentOptions.setOffset(0); 
   downloadDocumentOptions.setLength(-1); 
   ILeadStream stream = LeadStreamFactory.create(documentFile1); 
 
   downloadDocumentOptions.setStream(stream); 
   long bytes = DocumentFactory.downloadDocument(downloadDocumentOptions); 
   System.out.printf("Downloaded %s bytes into the stream%n", bytes); 
 
   long annotations = DocumentFactory.downloadAnnotations(downloadDocumentOptions); 
   System.out.println(annotations + " annotations downloaded"); 
 
   // The following method is obsolete. Use 
   // DownloadAnnotations(DownloadDocumentOptions) instead 
   int annotations2 = DocumentFactory.downloadAnnotations(downloadDocumentOptions.getCache(), 
         downloadDocumentOptions.getDocumentId(), downloadDocumentOptions.getOffset(), (int) bytes, stream); 
   System.out.println(annotations2 + " annotations downloaded"); 
 
   // Save the stream to a file and show it 
   stream.dispose(); 
 
   // Download it again, this time we will buffer it 32K at a time 
   downloadDocumentOptions = new DownloadDocumentOptions(); 
   downloadDocumentOptions.setCache(cache); 
   downloadDocumentOptions.setDocumentId(documentId); 
   byte[] buffer = new byte[1024 * 32]; 
   FileOutputStream output = new FileOutputStream(documentFile2); 
 
   // Offset to where we are: 
   long offset = 0; 
 
   bytes = 0; 
   do { 
      downloadDocumentOptions.setOffset(offset); 
      downloadDocumentOptions.setLength(buffer.length); 
      downloadDocumentOptions.setData(buffer); 
      downloadDocumentOptions.setDataOffset(0); 
      bytes = (int) DocumentFactory.downloadDocument(downloadDocumentOptions); 
      if (bytes > 0) { 
         System.out.printf("Downloaded %s bytes into the buffer%n", bytes); 
         // Next chunk 
         offset += bytes; 
         output.write(buffer, 0, (int) bytes); 
 
         // The following method is obsolete. Use 
         // DownloadAnnotations(DownloadDocumentOptions) instead 
         annotations = DocumentFactory.downloadAnnotations(downloadDocumentOptions.getCache(), 
               downloadDocumentOptions.getDocumentId(), downloadDocumentOptions.getOffset(), buffer, 
               downloadDocumentOptions.getDataOffset(), buffer.length); 
         System.out.println(annotations + " annotations downloaded"); 
      } 
   } while (bytes > 0); 
 
   // We are done, clean up 
   LoadFromCacheOptions deleteFromCacheOptions = new LoadFromCacheOptions(); 
   deleteFromCacheOptions.setCache(cache); 
   deleteFromCacheOptions.setDocumentId(documentId); 
   DocumentFactory.deleteFromCache(deleteFromCacheOptions); 
   assertTrue(new File(documentFile2).exists()); 
   output.close(); 
}

Requirements

Target Platforms

Reference

DocumentFactory Class

DocumentFactory Members

Leadtools.Document Namespace

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Help Version 23.0.2024.2.29

Leadtools.Document Assembly

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Leadtools.Document Namespace

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