WebRequest to connect to the Wikipedia API

NickJ picture NickJ · Apr 21, 2009 · Viewed 14.8k times · Source

This may be a pathetically simple problem, but I cannot seem to format the post webrequest/response to get data from the Wikipedia API. I have posted my code below if anyone can help me see my problem.

    string pgTitle = txtPageTitle.Text;

    Uri address = new Uri("http://en.wikipedia.org/w/api.php");

    HttpWebRequest request = WebRequest.Create(address) as HttpWebRequest;

    request.Method = "POST";
    request.ContentType = "application/x-www-form-urlencoded";

    string action = "query";
    string query = pgTitle;

    StringBuilder data = new StringBuilder();
    data.Append("action=" + HttpUtility.UrlEncode(action));
    data.Append("&query=" + HttpUtility.UrlEncode(query));

    byte[] byteData = UTF8Encoding.UTF8.GetBytes(data.ToString());

    request.ContentLength = byteData.Length;

    using (Stream postStream = request.GetRequestStream())
    {
        postStream.Write(byteData, 0, byteData.Length);
    }

    using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
    {
        // Get the response stream.
        StreamReader reader = new StreamReader(response.GetResponseStream());

        divWikiData.InnerText = reader.ReadToEnd();
    }

Answer

Keltex picture Keltex · Apr 21, 2009

You might want to try a GET request first because it's a little simpler (you will only need to POST for wikipedia login). For example, try to simulate this request:

http://en.wikipedia.org/w/api.php?action=query&prop=images&titles=Main%20Page

Here's the code:

HttpWebRequest myRequest =
  (HttpWebRequest)WebRequest.Create("http://en.wikipedia.org/w/api.php?action=query&prop=images&titles=Main%20Page");
using (HttpWebResponse response = (HttpWebResponse)myRequest.GetResponse())
{
    string ResponseText;
    using (StreamReader reader = new StreamReader(response.GetResponseStream()))
    {
        ResponseText = reader.ReadToEnd();
    }
}

Edit: The other problem he was experiencing on the POST request was, The exception is : The remote server returned an error: (417) Expectation failed. It can be solved by setting:

System.Net.ServicePointManager.Expect100Continue = false;

(This is from: HTTP POST Returns Error: 417 "Expectation Failed.")