How Can I get the real name of an image from a url

Question

I have the next url about an image:

https://i.discogs.com/HE17wcv1sG6NDK1WcVyoQjSqUGDZva3SYvm6vXoCMOo/rs:fit/g:sm/q:90/h:600/w:600/czM6Ly9kaXNjb2dz/LWRhdGFiYXNlLWlt/YWdlcy9SLTk2OTY5/NjktMTQ4NDkzNzkw/Ni00MDcyLmpwZWc.jpeg

If I open the url with the navigator and then I press de right button to save this image in my hard disc the name solved by the navigator for this file image is distinct. How can i get the last name of the file in c#?

Answer 1

If you're set on using WebClient then you can download the data into memory, check for the Content-Disposition header, and then change the filename accordingly. I've added commented out parts that you can use instead of their synchronous counterparts if you're using this method asynchronously.

// private static async Task DownloadImageAsync(string url, string folder)
private static void DownloadImage(string url, string folder)
{
    var uri = new Uri(url);
    string fileName = Path.GetFileName(uri.AbsolutePath);
    WebClient client = new WebClient();
    // byte[] fileData = await client.DownloadDataTaskAsync(url);
    byte[] fileData = client.DownloadData(url);

    string disposition = client.ResponseHeaders.Get("Content-Disposition"); // try to get the disposition
    if (!string.IsNullOrEmpty(disposition) // check it has a value
        && ContentDispositionHeaderValue.TryParse(disposition, out var parsedDisposition) // check it can be parsed
        && !string.IsNullOrEmpty(parsedDisposition.FileName)) // check a filename is specified
    {
        fileName = parsedDisposition.FileName.Trim('"'); // replace the normal filename with the parsed one
    }
    // await File.WriteAllBytesAsync(Path.Combine(folder, fileName), fileData);
    File.WriteAllBytes(Path.Combine(folder, fileName), fileData);
}

Usage: DownloadImage(myurl, @"C:\Users\Me\Desktop");

---

That said, WebClient is a bit old-fashioned and you should probably use HttpClient for newer developments:

private static async Task DownloadImageAsync(string url, string folder)
{
    var uri = new Uri(url);
    string fileName = Path.GetFileName(uri.AbsolutePath);

    using var response = await _httpClient.GetAsync(url);
    response.EnsureSuccessStatusCode();

    if (!string.IsNullOrEmpty(response.Content.Headers.ContentDisposition?.FileName))
    {
        fileName = response.Content.Headers.ContentDisposition.FileName.Trim('"');
    }

    using var outputFile = File.Create(Path.Combine(folder, fileName));
    await response.Content.CopyToAsync(outputFile);
}

Usage: await DownloadImageAsync(myurl, @"C:\Users\Me\Desktop");

Microsoft recommend using a single static instance of HttpClient throughout your application ( docs ). This does have pitfalls though, so depending on your application, you might want to look into using IHttpClientFactory , which works to solve the issues that come from using a static HttpClient .