Update part of a file

The following example shows you how to write content into part of an existing file (PUT with Content-Range). This is supported by Apache mod_dav, but not by all servers. Use it only with a server known to support it: a server that ignores Content-Range replaces the whole file with the content.

C# example

using System;
using System.IO;
using System.Net;
using System.Threading.Tasks;
using Independentsoft.Webdav;

namespace Sample
{
    class Program
    {
        static async Task Main(string[] args)
        {
            NetworkCredential credential = new NetworkCredential("username", "password");

            using (WebdavClient client = new WebdavClient(credential))
            {
                client.BaseAddress = new Uri("https://myserver/dav/");

                byte[] header = System.Text.Encoding.ASCII.GetBytes("UPDATED ");

                try
                {
                    using (MemoryStream content = new MemoryStream(header))
                    {
                        // Overwrite the first bytes of the file.
                        await client.UploadRange("documents/notes.txt", content, 0);
                    }
                }
                catch (WebdavException e) when (e.StatusCode == HttpStatusCode.BadRequest || e.StatusCode == HttpStatusCode.NotImplemented)
                {
                    Console.WriteLine("The server does not support updating part of a file.");
                    return;
                }

                using (StreamReader reader = new StreamReader(await client.OpenRead("documents/notes.txt")))
                {
                    Console.WriteLine(await reader.ReadToEndAsync());
                }
            }
        }
    }
}

VB example

Imports System
Imports System.IO
Imports System.Net
Imports System.Threading.Tasks
Imports Independentsoft.Webdav

Namespace Sample
    Module Program
        Sub Main(args As String())
            RunAsync().GetAwaiter().GetResult()
        End Sub

        Private Async Function RunAsync() As Task
            Dim credential As New NetworkCredential("username", "password")

            Using client As New WebdavClient(credential)
                client.BaseAddress = New Uri("https://myserver/dav/")

                Dim header As Byte() = System.Text.Encoding.ASCII.GetBytes("UPDATED ")

                Try
                    Using content As New MemoryStream(header)
                        ' Overwrite the first bytes of the file.
                        Await client.UploadRange("documents/notes.txt", content, 0)
                    End Using
                Catch e As WebdavException When e.StatusCode = HttpStatusCode.BadRequest OrElse e.StatusCode = HttpStatusCode.NotImplemented
                    Console.WriteLine("The server does not support updating part of a file.")
                    Return
                End Try

                Using reader As New StreamReader(Await client.OpenRead("documents/notes.txt"))
                    Console.WriteLine(Await reader.ReadToEndAsync())
                End Using
            End Using
        End Function
    End Module
End Namespace

WebDAV .NET > Tutorial > Update part of a file

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