BuildLtiRequestViewBag

gistfile1.cs

private void BuildLtiRequestViewBag(Assignment assignment)
{
    // Start with the basic and required parameters
    var parameters = BuildBaseLtiRequestData(assignment);

    // Add recommended and optional parameters
    AddOptionalParameters(assignment, parameters);

    // Add version specific parameters
    if (assignment.LtiVersionId == LtiVersion.Version10)
        AddLti10Parameters(assignment, parameters);
    if (assignment.LtiVersionId == LtiVersion.Version11)
        AddLti11Parameters(assignment, parameters);

    // Finally, calculate the OAuth signature and send the data over to the view 
    // for rendering in the client browser. See Views/Assignment/Launch
    var uri = new Uri(assignment.Url);
    var signatureBase = SignatureBase.Create("POST", uri, parameters);
    var signatureProvider = new HmacSha1SigningProvider();

    ViewBag.Signature = signatureProvider.ComputeSignature(signatureBase, assignment.Secret,
        string.Empty);
    ViewBag.Action = uri.ToString();
    ViewBag.NameValues = HttpUtility.ParseQueryString(parameters.ToQueryStringFormat());
 }