C# Download file from URL

Question

Can anybody tell me how i can download file in my C# program from that URL: http://www.cryptopro.ru/products/cades/plugin/get_2_0

I try to use WebClient.DownloadFile, but i'm getting only html page instead of file.

Fluctuant

Well, your url points to a html file and that's what you get. Which file do you want to download? – Eutectoid

If you try to open that URL in any browser, downloading begins. – Fluctuant

Answer 1

Looking in Fiddler the request fails if there is not a legitimate U/A string, so:

WebClient wb = new WebClient();
wb.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.33 Safari/537.36");
wb.DownloadFile("http://www.cryptopro.ru/products/cades/plugin/get_2_0/cadeplugin.exe", "c:\\xxx\\xxx.exe");

Fafnir

I added above header but it didn't work for me. I am trying to download a encrypted text and an exe file. – Minter

Answer 2

I belive this would do the trick.

WebClient wb = new WebClient();
wb.DownloadFile("http://www.cryptopro.ru/products/cades/plugin/get_2_0/cadeplugin.exe","file.exe");

Bil

Answer 3

If you need to know the download status or use credentials in order to make the request, I'll suggest this solution:

WebClient client = new WebClient();
Uri ur = new Uri("http://remoteserver.do/images/img.jpg");
client.Credentials = new NetworkCredential("username", "password");
client.DownloadProgressChanged += WebClientDownloadProgressChanged;
client.DownloadDataCompleted += WebClientDownloadCompleted;
client.DownloadFileAsync(ur, @"C:\path\newImage.jpg");

And her it is the implementation of the callbacks:

void WebClientDownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
    Console.WriteLine("Download status: {0}%.", e.ProgressPercentage);
}

void WebClientDownloadCompleted(object sender, DownloadDataCompletedEventArgs e)
{
    Console.WriteLine("Download finished!");
}

Lugsail

Should be DownloadFileCompleted instead of DownloadDataCompleted. – Sericin

Answer 4

Try WebClient.DownloadData

You would get response in the form of byte[] then you can do whatever you want with that.

Sporangium

Answer 5

Sometimes a server would not let you download files with scripts/code. to take care of this you need to set user agent header to fool the server that the request is coming from browser. using the following code, it works. Tested ok

 var webClient=new WebClient();
 webClient.Headers["User-Agent"] =
                "Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.85 Safari/537.36";
 webClient.DownloadFile("the url","path to downloaded file");

this will work as you expect, and you can download file.

Zoril

Answer 6

Since this was the first result in my Google search, I thought it would be beneficial to provide an updated answer.

Using HttpClient

Since WebClient is deprecated, it's recommended to use HttpClient for modern C# applications. However, HttpClient lacks some features like progress reporting and status change events that WebClient has. Here's an example of how to use HttpClient to download a file:

using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        string url = "http://www.cryptopro.ru/products/cades/plugin/get_2_0";
        string filePath = "c:\\path\\to\\save\\file.exe";

        using (HttpClient client = new HttpClient())
        {
            try
            {
                HttpResponseMessage response = await client.GetAsync(url, HttpCompletionOption.ResponseHeadersRead);
                response.EnsureSuccessStatusCode();

                using (var fileStream = new System.IO.FileStream(filePath, System.IO.FileMode.Create, System.IO.FileAccess.Write, System.IO.FileShare.None))
                {
                    await response.Content.CopyToAsync(fileStream);
                }

                Console.WriteLine("File downloaded successfully.");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error: {ex.Message}");
            }
        }
    }
}

Using DownloadAssistant Library

The DownloadAssistant is built on top of HttpClient and provides additional features such as progress reporting, resumable downloads, and more. Here's an example of how to use DownloadAssistant:

1. Install the DownloadAssistant library via NuGet:

   Install-Package Shard.DownloadAssistant
   

2. Example code using DownloadAssistant:

using System;
using DownloadAssistant.Requests;

class Program
{
    static async Task Main(string[] args)
    {
        string url = "http://www.cryptopro.ru/products/cades/plugin/get_2_0";

        LoadRequestOptions requestOptions = new LoadRequestOptions
        {
            FileName = "downloadfile",
            DestinationPath = @"C:\path\to\save",
            RequestCompleated = (req, url) => Console.WriteLine($"Finished successfully: {url}")
        };

        var request = new LoadRequest(url, requestOptions);
        request.Progress.ProgressChanged += (progress, value) => Console.WriteLine($"Download Progress: {value * 100:F2}%");
        await request.Task;
    }
}

Explanation

• HttpClient Example: This example demonstrates how to use HttpClient to download a file asynchronously. It handles the response and writes it to a file stream.
• DownloadAssistant Example: This example shows how to use the DownloadAssistant library, which provides additional features and simplifies the download process.

Conclusion

Both methods are valid, but if you need advanced features like progress reporting and resumable downloads, the DownloadAssistant library is a better choice. Otherwise, HttpClient is better for basic file downloads.

Complexity