c# WebRequest to connect to wikipedia API

Question

Hey,

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 1

You seem to be pushing the input data on HTTP POST, but it seems you should use HTTP GET.

From the MediaWiki API docs:

The API takes its input through parameters in the query string. Every module (and every action=query submodule) has its own set of parameters, which is listed in the documentation and in action=help, and can be retrieved through action=paraminfo. http://www.mediawiki.org/wiki/API:Data_formats

Answer 2

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://stackoverflow.com/questions/566437/http-post-returns-the-error-417-expectation-failed-c-resolved)

Answer 3

Hi, I'm currently in the final stages of implementing an C# MediaWiki API which allows the easy scripting of most MediaWiki viewing and editing actions.

The main API is here: http://o2platform.googlecode.com/svn/trunk/O2%20-%20All%20Active%20Projects/O2_XRules_Database/_Rules/APIs/OwaspAPI.cs and here is an example of the API in use:

var wiki = new O2MediaWikiAPI("http://www.o2platform.com/api.php");

wiki.login(userName, password);

var page = "Test"; // "Main_Page";

wiki.editPage(page,"Test content2");

var rawWikiText = wiki.raw(page);
var htmlText = wiki.html(page);

return rawWikiText.line().line() + htmlText;

Answer 4

My apologies, I don't have enough rep to comment - this is actually a comment on Keltex's answer.

I found that you have to set the HttpWebRequest.UserAgent property [^], and identify your client when calling the API. Else you will get a 403 Error back.

So, I would add

myRequest.UserAgent = "MyWikiClient\1.0";

or the like, to Keltex's code.