WebClient 403 Forbidden

Question

I can download this by hand in IE.

http://scholar.google.com/scholar.ris?q=info:j8ymU9rzMsEJ:scholar.google.com/&output=citation&hl=zh-CN&as_sdt=2000&oe=GB&ct=citation&cd=0

But, using follow code

WebClient client = new WebClient();
client.DownloadFile(address, filename);

Show Exception: 403 Forbidden

What's wrong? How can I do that?

others

http://scholar.google.com/scholar.ris?q=info:sskrpr5jlLwJ:scholar.google.com/&output=citation&hl=zh-CN&as_sdt=2000&oe=GB&ct=citation&cd=1

Answer 1

Just add a simple line before you make your download:

string url = ... 
string fileName = ...

WebClient wb = new WebClient();
wb.Headers.Add("User-Agent: Other");   //that is the simple line!
wb.DownloadFile(url, fileName);

That's it.

Answer 2

403 may also be caused by TLS issues. To verify, you should check the text of the WebException.Response object.

     catch (WebException ex)
     {
        if (ex.Response != null)
        {
           var response = ex.Response;
           var dataStream = response.GetResponseStream();
           var reader = new StreamReader(dataStream);
           var details = reader.ReadToEnd();
        }
     }

If it is TLS then try adding this to your code to force TLS1.2.

For .net4:

ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;

For .net4.5 or later:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;