How to get File in Content-Disposition attachment using WebRequest and/or HTML Agility Pack

Question

I'm developting a web crawler that will download a PDF file from a website.

I checked the source code of the website before and I discovery that the button which download the PDF is actually a submit input to a form. That form retrives the file in Content-Disposition header in response.

Here's a picture of it:

My question is, how to get this file using web request (or HTML Agility pack). I tried in this way, but the hearder returns null.

HttpWebResponse response = (HttpWebResponse)req.GetResponse();
string file = response.Headers["Content-Disposition"];

Thanks in advance

Answer 1

I already have my answers, here is what I've done to get the file

response = (HttpWebResponse)request.GetResponse();
stream = response.GetResponseStream();
byte[] retorno = ReadToEnd(stream);
response.Close();
stream.Close();

public static byte[] ReadToEnd(System.IO.Stream stream)
{
    long originalPosition = 0;

    if (stream.CanSeek)
    {
        originalPosition = stream.Position;
        stream.Position = 0;
    }

    try
    {
        byte[] readBuffer = new byte[4096];

        int totalBytesRead = 0;
        int bytesRead;

        while ((bytesRead = stream.Read(readBuffer, totalBytesRead, readBuffer.Length - totalBytesRead)) > 0)
        {
            totalBytesRead += bytesRead;

            if (totalBytesRead == readBuffer.Length)
            {
                int nextByte = stream.ReadByte();
                if (nextByte != -1)
                {
                    byte[] temp = new byte[readBuffer.Length * 2];
                    Buffer.BlockCopy(readBuffer, 0, temp, 0, readBuffer.Length);
                    Buffer.SetByte(temp, totalBytesRead, (byte)nextByte);
                    readBuffer = temp;
                    totalBytesRead++;
                }
            }
        }

        byte[] buffer = readBuffer;
        if (readBuffer.Length != totalBytesRead)
        {
            buffer = new byte[totalBytesRead];
            Buffer.BlockCopy(readBuffer, 0, buffer, 0, totalBytesRead);
        }
        return buffer;
    }
    finally
    {
        if (stream.CanSeek)
        {
            stream.Position = originalPosition;
        }
    }
}

thanks