How to Download a File from a Website in C#

How to download a file from a website in C#

With the WebClient class:

using System.Net;
//...
WebClient Client = new WebClient ();
Client.DownloadFile("http://i.stackoverflow.com/Content/Img/stackoverflow-logo-250.png", @"C:\folder\stackoverflowlogo.png");

How to download a file from an URL to a server folder

can use System.Net.WebClient

using (WebClient Client = new WebClient ())
{
    Client.DownloadFile (
            // Param1 = Link of file
            new System.Uri("Given URL"),
            // Param2 = Path to save
            "On SERVER PATH"
        );
}

How to download a file from a URL using c#

Lasse Vågsæther Karlsen is correct. Your browser is smart enough to decompress the file because the response contains the header:

content-encoding:"gzip"

You can download and decompress the file with this code (adjust accordingly for your file name, path, etc.)

void Main()
{
    using (var client = new WebClient())
    {
        client.Headers.Add("accept", "*/*");
        byte[] filedata = client.DownloadData("http://members.tsetmc.com/tsev2/excel/MarketWatchPlus.aspx?d=1396-08-08");

        using (MemoryStream ms = new MemoryStream(filedata))
        {    
            using (FileStream decompressedFileStream = File.Create("c:\\deleteme\\test.xlsx"))
            {
                using (GZipStream decompressionStream = new GZipStream(ms, CompressionMode.Decompress))
                {
                    decompressionStream.CopyTo(decompressedFileStream);
                }
            }
        }
    }
}

Downloading a file from a website using C#

I tested that URL with wget, and got a 403 error. I was able to solve that problem by adding a user-agent string to the header

Try adding a user-agent string to the header, using webClient.Headers.Add(HttpRequestHeader.UserAgent, "blah")

Download a file from website, without specific file url

Try this approach:

var client = new HttpClient
{
    BaseAddress = new Uri("https://thunderstore.io/")
};

var response = await client.GetStreamAsync("package/download/Raus/IonUtility/1.0.1/");

var fn = Path.GetTempFileName();

using (var file = File.OpenWrite(fn))
{
    await response.CopyToAsync(file);
}

At the end fn will hold the local file name. There is no dialog and you have the full control.

C# Download file from URL

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");

How to Download a file from a website programatically c#

You'll need to post your data to the server with your client request as explained by @Peter.

This is an ASP.net page, and therefore it requires that you send some data on postback in order to complete the callback.

Using google, I was able to find this as a proof of concept.

The following is a snippet I wrote in Linqpad to test it out. Here it is:

void Main()
{

    WebClient webClient = new WebClient();

    byte[] b = webClient.DownloadData("http://www.mcxindia.com/sitepages/BhavCopyDateWise.aspx");

    string s = System.Text.Encoding.UTF8.GetString(b);

    var __EVENTVALIDATION = ExtractVariable(s, "__EVENTVALIDATION");

    __EVENTVALIDATION.Dump();

    var forms = new NameValueCollection(); 

    forms["__EVENTTARGET"] = "btnLink_Excel";
    forms["__EVENTARGUMENT"] = "";
    forms["__VIEWSTATE"] = ExtractVariable(s, "__VIEWSTATE");
    forms["mTbdate"] = "11%2F15%2F2011";
    forms["__EVENTVALIDATION"] = __EVENTVALIDATION;

    webClient.Headers.Set(HttpRequestHeader.ContentType, "application/x-www-form-urlencoded");

    var responseData = webClient.UploadValues(@"http://www.mcxindia.com/sitepages/BhavCopyDateWise.aspx", "POST", forms); 
    System.IO.File.WriteAllBytes(@"c:\11152011.csv", responseData);
}

private static string ExtractVariable(string s, string valueName)
{
     string tokenStart = valueName + "\" value=\"";
     string tokenEnd = "\" />";

     int start = s.IndexOf(tokenStart) + tokenStart.Length;
     int length = s.IndexOf(tokenEnd, start) - start;
     return s.Substring(start, length);
}

C# download file from the web with login

This should do the job!

        CookieContainer cookieJar = new CookieContainer();
        CookieAwareWebClient http = new CookieAwareWebClient(cookieJar);

        string postData = "name=********&password=*********&submit=submit";
        string response = http.UploadString("https://www.loginpage.com/", postData);

        // validate your login! 

        http.DownloadFile("https://www.loginpage.com/export_excel.php?export_type=list", "my_excel.xls");

I have used CookieAwareWebClient

public class CookieAwareWebClient : WebClient
{
    public CookieContainer CookieContainer { get; set; }
    public Uri Uri { get; set; }

    public CookieAwareWebClient()
        : this(new CookieContainer())
    {
    }

    public CookieAwareWebClient(CookieContainer cookies)
    {
        this.CookieContainer = cookies;
    }

    protected override WebRequest GetWebRequest(Uri address)
    {
        WebRequest request = base.GetWebRequest(address);
        if (request is HttpWebRequest)
        {
            (request as HttpWebRequest).CookieContainer = this.CookieContainer;
        }
        HttpWebRequest httpRequest = (HttpWebRequest)request;
        httpRequest.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
        return httpRequest;
    }

    protected override WebResponse GetWebResponse(WebRequest request)
    {
        WebResponse response = base.GetWebResponse(request);
        String setCookieHeader = response.Headers[HttpResponseHeader.SetCookie];

        if (setCookieHeader != null)
        {
            //do something if needed to parse out the cookie.
            if (setCookieHeader != null)
            {
                Cookie cookie = new Cookie(); //create cookie
                this.CookieContainer.Add(cookie);
            }
        }
        return response;
    }
}

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Source & Credit for : CookieAwareWebClient

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