We now have a lay bet on Newcastle for £75 at 2.0 and a lay bet on Chelsea for £250 at 2.4 (again shown in blue on the available to back side of the market). These two bets can be matched against a lay bet on The Draw at a price of 12.0, since 2.0, 2.4, and 12.0 also form a 100% book. Balancing the stakes means that we need to take the full £75 at 2.0 on Newcastle, only £62.50 at 2.4 on Chelsea, and £12.50 at 12.0 on The Draw, which is the second virtual bet.

This leaves the following market:

This time we can't continue the process since there is no valid price for a virtual bet on The Draw that would result i a 100% book, and so we can stop calculating the virtual bets. Again, the virtual bets are just the bets that would have been matched had we received a sufficiently large lay bet at 1000; in this example, £75 at 6.0 and £12.50 at 12.0. We take these virtual bets and merge them with the existing bets on the market to generate the following market view (with the virtual bets shown in orange):

Sample Code

As well as sample code developed by Betfair, this page allows you to find sample code or documentation prepared by members of the Developer Program community. If you would like to contribute to this space, please contact bdp @betfair.com.

All Betfair developed sample code follows a typical work flow:

Find the next UK Horse Racing Win market Get prices for the market

Place a bet on the market

Handle the error returned by the API when the bet fails as it is below the minimum stake size.

Please Note: In order to aide ease of understanding, the basic Betfair samples are not intended to show certain best practices for speed and throughput. Well designed applications should follow the best practices for client design of the application/language platform and should optimise on an HTTP request level with features such as requesting gzip'd responses and http connection keep alives.

The following samples are currently available:

using (Stream stream = response.GetResponseStream())

using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))

{

var jsonResponse = JsonConvert.Import<T>(reader); Console.WriteLine("Got Response: " +

JsonConvert.Serialize<JsonResponse<T>>(jsonResponse));

if (jsonResponse.HasError)

{

throw ReconstituteException(jsonResponse.Error);

}

else

{

return jsonResponse.Result;

}

}

}

private static System.Exception ReconstituteException(Api_ng_sample_code.TO.Exception ex)

{

var data = ex.Data;

// API-NG exception -- it must have "data" element to tell us which

exception

var exceptionName = data.Property("exceptionname").Value.ToString(); var exceptionData = data.Property(exceptionName).Value.ToString(); return JsonConvert.Deserialize<APINGException>(exceptionData);

}

}

}

Example usage of the code above is:

public IList<EventTypeResult> listEventTypes(MarketFilter marketFilter, string locale = null)

{

var args = new Dictionary<string, object>(); args[FILTER] = marketFilter;

args[LOCALE] = locale;

return Invoke<List<EventTypeResult>>(LIST_EVENT_TYPES_METHOD, args);

}

Rescript

Below is the rescript implementation of the functionality mentioned above

protected HttpWebRequest CreateWebRequest(String restEndPoint)

{

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(restEndPoint); request.Method = "POST";

request.ContentType = "application/json"; request.ContentLength = 0; request.Headers.Add(HttpRequestHeader.AcceptCharset, "UTF-8"); request.Accept = "application/json"; request.Headers.Add(CustomHeaders);

return request;

}

public T Invoke<T>(string method, IDictionary<string, object> args = null)

{

if (method == null)

throw new ArgumentNullException("method"); if (method.Length == 0)

throw new ArgumentException(null, "method");

var restEndpoint = EndPoint + method + "/"; var request = CreateWebRequest(restEndpoint);

var postData = JsonConvert.Serialize<IDictionary<string, object>>(args)

+ "}";

Console.WriteLine("Calling: " + method + " With args: " + postData);

var bytes = Encoding.GetEncoding("UTF-8").GetBytes(postData); request.ContentLength = bytes.Length;

using (Stream stream = request.GetRequestStream())

{

stream.Write(bytes, 0, bytes.Length);

}

using (WebResponse response = GetWebResponse(request))

using (Stream stream = response.GetResponseStream())

using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))

{

var jsonResponse = reader.ReadToEnd(); Console.WriteLine("Got response: " + jsonResponse); if (jsonResponse.Contains("exception")) {

throw ReconstituteException(JsonConvert.Deserialize<Api_ng_sample_code.TO.Exception>(jsonR esponse));

}

return JsonConvert.Deserialize<T>(jsonResponse);

}

}

private static System.Exception ReconstituteException(Api_ng_sample_code.TO.Exception ex)

{

var data = ex.Detail;

// API-NG exception -- it must have "data" element to tell us which

exception

var exceptionName = data.Property("exceptionname").Value.ToString(); var exceptionData = data.Property(exceptionName).Value.ToString();