IItemContentGetReadStreamAsync Method (Int64, Int64, String, IDictionaryString, String, CancellationToken)

IT Hit WebDAV Classes Reference

Loads part of the content of the file from WebDAV server using eTag to ensure the content is up-to-date.

Namespace: ITHit.WebDAV.Client
Assembly: ITHit.WebDAV.Client (in ITHit.WebDAV.Client.dll) Version: 6.0.4052-Beta

Syntax

C++

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Task<ContentStream> GetReadStreamAsync(
	long startIndex,
	long count,
	string eTag,
	IDictionary<string, string> headers = null,
	CancellationToken cancellationToken = null
)

Function GetReadStreamAsync ( 
	startIndex As Long,
	count As Long,
	eTag As String,
	Optional headers As IDictionary(Of String, String) = Nothing,
	Optional cancellationToken As CancellationToken = Nothing
) As Task(Of ContentStream)

Task<ContentStream^>^ GetReadStreamAsync(
	long long startIndex, 
	long long count, 
	String^ eTag, 
	IDictionary<String^, String^>^ headers = nullptr, 
	CancellationToken cancellationToken = nullptr
)

abstract GetReadStreamAsync : 
        startIndex : int64 * 
        count : int64 * 
        eTag : string * 
        ?headers : IDictionary<string, string> * 
        ?cancellationToken : CancellationToken 
(* Defaults:
        let _headers = defaultArg headers null
        let _cancellationToken = defaultArg cancellationToken null
*)
-> Task<ContentStream>

Parameters

startIndex: Type: SystemInt64
Start position to retrieve count number of bytes from.
count: Type: SystemInt64
Number of bytes to retrieve.
eTag: Type: SystemString
The ETag that will be passed in the If-Range header.
headers (Optional): Type: System.Collections.GenericIDictionaryString, String
Request headers.
cancellationToken (Optional): Type: System.ThreadingCancellationToken
Propagates notification that operations should be canceled.

Return Value

Type: TaskContentStream
Stream to read file content.

Exceptions

Exception	Condition
NotFoundException	This resource doesn't exist on the server.
WebDavHttpException	Server returned unknown error.
WebDavException	Unexpected error occurred.

Remarks

Loads part of the content of the file from WebDAV server if it's content was not changed. If the content was modified the complete new content is returned.

Examples

This sample shows how to use the [!:GetReadStreamAsync(long,long,string)] method. First 1024 bytes of server file are already saved to local file. Code tries to download the rest of the file content.

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string license = "<?xml version='1.0' encoding='utf...
WebDavSession session = new WebDavSession(license);
session.Credentials = new NetworkCredential("User1", "pwd");
IFolder folder = await session.GetFolderAsync(new Uri("https://server:8080/Sales"));
FileInfo file = new FileInfo("C:\\Temp\\Products.cff");
IFile file = await folder.GetResourceAsync(file.Name);

string etag = file.Etag;
int bufSize = 1048576; // 1Mb
byte[] buffer = new byte[bufSize];
int totalWritten = 10;

using (ContentStream stream = await file.GetReadStreamAsync(totalWritten, resource.ContentLength, etag, out contentModified))
{
    if (stream.ContentModified)
        totalWritten = 0; // entire file content is returned
    using (FileStream fs = file.OpenWrite())
    {
        fs.Seek(totalWritten, SeekOrigin.Begin);
        int bytesRead;
        while ((bytesRead = (await stream.ReadAsync(buffer, 0, bufSize))) > 0)
            await fs.WriteAsync(buffer, 0, bytesRead);
    }
}

Reference

IItemContent Interface

GetReadStreamAsync Overload

ITHit.WebDAV.Client Namespace