/// <summary>
/// Discovers topic and hub URLs based on publisher's content URL and performs subscription request.
/// </summary>
/// <param name="parameters">The parameters.</param>
/// <param name="cancellationToken">The cancellation token to cancel operation.</param>
/// <returns>The task object representing the asynchronous operation.</returns>
public async Task <WebSubSubscribedUrls> SubscribeAsync(WebSubSubscribeParameters parameters, CancellationToken cancellationToken)
{
if (parameters == null)
{
throw new ArgumentNullException(nameof(parameters));
}
WebSubDiscoveredUrls discovery = await _webSubDiscoverer.DiscoverAsync(parameters.ContentUrl, cancellationToken);
await CallOnDiscovered(parameters, discovery, cancellationToken);
string subscriptionHubUrl = null;
Dictionary <string, HttpResponseMessage> hubsResponses = new Dictionary <string, HttpResponseMessage>();
FormUrlEncodedContent subscribeRequestContent = PrepareSubscribeRequestContent(discovery.Topic, parameters);
foreach (string hubUrl in discovery.Hubs)
{
HttpResponseMessage hubResponse = await _httpClient.PostAsync(hubUrl, subscribeRequestContent, cancellationToken);
if (hubResponse.StatusCode == HttpStatusCode.Accepted)
{
subscriptionHubUrl = hubUrl;
break;
}
hubsResponses.Add(hubUrl, hubResponse);
}
if (String.IsNullOrWhiteSpace(subscriptionHubUrl))
{
throw new WebSubSubscriptionException("None of discovered hubs have accepted the request.", hubsResponses);
}
return(new WebSubSubscribedUrls(discovery.Topic, subscriptionHubUrl));
}
private static async Task CallOnDiscovered(WebSubSubscribeParameters parameters, WebSubDiscoveredUrls discovery, CancellationToken cancellationToken)
{
parameters.OnDiscovered?.Invoke(discovery);
if (parameters.OnDiscoveredAsync != null)
{
await parameters.OnDiscoveredAsync(discovery, cancellationToken);
}
}
/// <summary>
/// Discovers topic and hub URLs based on publisher's content URL and performs subscription request.
/// </summary>
/// <param name="parameters">The parameters.</param>
/// <returns>The task object representing the asynchronous operation. The result is URLs to which the subscription has been made.</returns>
public Task <WebSubSubscribedUrls> SubscribeAsync(WebSubSubscribeParameters parameters)
{
return(SubscribeAsync(parameters, CancellationToken.None));
}
private static FormUrlEncodedContent PrepareSubscribeRequestContent(string topicUrl, WebSubSubscribeParameters parameters)
{
List <KeyValuePair <string, string> > subscribeParameters = new List <KeyValuePair <string, string> >
{
new KeyValuePair <string, string>(HUB_MODE_PARAMETER_NAME, HUB_MODE_SUBCRIBE),
new KeyValuePair <string, string>(HUB_TOPIC_PARAMETER_NAME, topicUrl),
new KeyValuePair <string, string>(HUB_CALLBACK_PARAMETER_NAME, parameters.CallbackUrl)
};
if (parameters.LeaseSeconds.HasValue)
{
subscribeParameters.Add(new KeyValuePair <string, string>(HUB_LEASE_SECONDS_PARAMETER_NAME, parameters.LeaseSeconds.Value.ToString(CultureInfo.InvariantCulture)));
}
if (!String.IsNullOrWhiteSpace(parameters.Secret))
{
subscribeParameters.Add(new KeyValuePair <string, string>(HUB_SECRET_PARAMETER_NAME, parameters.Secret));
}
return(new FormUrlEncodedContent(subscribeParameters));
}
