Download files from url to local device in .Net Core

Question

In .Net 4.0 I used WebClient to download files from an url and save them on my local drive. But I am not able to achieve the same in .Net Core.

Can anyone help me out on this?

Are you sure asp.net-core-mvc is the right tag? From your question it seems you're talking about client software. Either way: Use `HttpClient` if you want to download files. — jAC, Aug 30 '17 at 11:55

score 35 · Accepted Answer · edited Dec 15 '18 at 17:09

35

WebClient is not available in .NET Core. (UPDATE: It is from 2.0) The usage of HttpClient in the System.Net.Http is therefore mandatory:

using System.Net.Http;
using System.Threading.Tasks;
...
public static async Task<byte[]> DownloadFile(string url)
{
    using (var client = new HttpClient())
    {

        using (var result = await client.GetAsync(url))
        {
            if (result.IsSuccessStatusCode)
            {
                return await result.Content.ReadAsByteArrayAsync();
            }

        }
    }
    return null;
}

edited Dec 15 '18 at 17:09

Eduardo Molteni

37,908
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answered Aug 30 '17 at 12:07

jAC

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12

For readers, be aware that you shouldn't use HttpClient this way. An option is to let HttpClientFactory handle the lifetime of an Httpclient object. Read [more](https://stackoverflow.com/questions/50912160/should-httpclient-instances-created-by-httpclientfactory-be-disposed) – Kristianne Nerona Aug 06 '19 at 00:47

score 22 · Answer 2 · answered Dec 15 '18 at 17:08

22

WebClient is available from .net core 2.0

var wc = new System.Net.WebClient();
wc.DownloadFile( URL, @"c:\temp\myfile.txt");

answered Dec 15 '18 at 17:08

Eduardo Molteni

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23
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203

Good to know, when you really want to download a file instead of using the content. – jAC Dec 18 '18 at 11:51
What happens if the remote file is not accessible, or the URL is wrong? Is there some way to know if the file was successfully downloaded or not? – Stian Mar 26 '19 at 12:31
1

@Stian It throws an exception – Eduardo Molteni Mar 27 '19 at 13:48
you should stop using webclient. – Leandro Bardelli Sep 26 '20 at 23:14
1

@Leandro: why?. – Eduardo Molteni Sep 28 '20 at 13:35
To begin, is not async. There is a lot of information about it, for e.g. this post is 6 yo: https://stackoverflow.com/questions/20530152/deciding-between-httpclient-and-webclient – Leandro Bardelli Sep 28 '20 at 13:40
1

You have the `DownloadFileAsync` method (this is .net core) – Eduardo Molteni Sep 30 '20 at 16:43

score 3 · Answer 3 · answered Apr 05 '22 at 10:27

In NetCore 6.0, you should use HttpClient instead of WebClient which is obsolete, and you have the async methods in the new File class.

The implementation is simple as the following:

static async Task DownloadFile(string url, string pathToSave, string fileName)
{
    var content = await GetUrlContent(url);
    if (content != null)
    {
        if (!Directory.Exists(pathToSave)) Directory.CreateDirectory(pathToSave);
        await File.WriteAllBytesAsync($"{pathToSave}/{fileName}", content);
    }
}

static async Task<byte[]?> GetUrlContent(string url)
{
    using (var client = new HttpClient())
    using (var result = await client.GetAsync(url))
        return result.IsSuccessStatusCode ? await result.Content.ReadAsByteArrayAsync():null;
}

Usage:

await DownloadFile("https://exampl.com/image.jpg", @"c:\DownloadedImages", "image.jpg");

Download files from url to local device in .Net Core

3 Answers3