/// <summary>
/// Gets the set of valid time arguments for a standard feed.
/// </summary>
/// <param name="feedId">The standard feed ID.</param>
/// <returns>An array of valid times. The array is always different from null, but it may be empty.</returns>
public static YouTubeTimeId[] GetValidTime(YouTubeStandardFeed feedId)
{
return YouTubeUri.timeFeedValidity[(int)feedId];
}
/// <summary>
/// Creates a standard feed URI.
/// </summary>
/// <param name="feedId">The feed ID.</param>
/// <param name="regionId">The region ID, it can be null.</param>
/// <param name="category">The category, it can be null.</param>
/// <param name="timeId">The time ID, it can be null.</param>
/// <param name="startIndex">The start index, it can be null.</param>
/// <param name="maxResults">The max results, it can be null.</param>
/// <returns>A URI for the selected standard feed.</returns>
public static Uri GetStandardFeed(
YouTubeStandardFeed feedId,
string regionId,
string category,
YouTubeTimeId? timeId,
int? startIndex,
int? maxResults
)
{
// Feed ID
string uriFeedId = YouTubeUri.standardFeedIds[(int)feedId];
// Region ID
string uriRegionId = null == regionId ? string.Empty : regionId + "/";
// Category
string uriCategory = null == category ? string.Empty : "_" + category;
StringBuilder builder = new StringBuilder(uriStandardVideoFeedPattern.FormatWith(uriRegionId, uriFeedId, uriCategory));
if (timeId != null)
{
builder.Append("&time=" + YouTubeUri.timeIds[(int)timeId]);
}
if (startIndex != null)
{
builder.Append("&start-index=" + startIndex);
}
if (maxResults != null)
{
builder.Append("&max-results=" + maxResults);
}
return new Uri(builder.ToString());
}
// Private methods.
/// <summary>
/// Crawls the feed at the specified parameters.
/// </summary>
/// <param name="asyncResult">The asynchronous result.</param>
/// <param name="feedId">The feed.</param>
/// <param name="timeId">The time.</param>
/// <param name="category">The category.</param>
/// <param name="regionId">The region.</param>
/// <param name="obj">The standard feed object.</param>
/// <returns>The crawl result.</returns>
private CrawlResult CrawlFeed(
SpiderAsyncResult asyncResult,
YouTubeStandardFeed feedId,
YouTubeTimeId timeId,
string category,
string regionId,
ref DbObjectStandardFeed obj)
{
// If the asynchronousn operation has been canceled, do nothing.
if (asyncResult.IsCanceled) return CrawlResult.Canceled;
// Compute the feed key.
string key = this.EncodeFeedKey(feedId, timeId, category, regionId);
// Compute the feed URI starting at index 1 and ask for 1 result.
Uri uri = YouTubeUri.GetStandardFeed(feedId, regionId, category, timeId, 1, 1);
// Create a new video request.
YouTubeRequestFeed<Video> request = new YouTubeRequestFeed<Video>(this.crawler.YouTube.Settings);
// Set the feed URL.
obj.Url = uri.AbsoluteUri;
try
{
// Begin an asynchronous request for the standard feed.
AsyncWebResult result = request.Begin(uri, (AsyncWebResult webResult) => { }) as AsyncWebResult;
// Add the result of the web operation to the collection of web requests.
AsyncWebOperation operation = asyncResult.AddAsyncWeb(request, result);
// Wait for the asynchronous operation to complete.
result.AsyncWaitHandle.WaitOne();
// Remove the result of the web operation from the collection of web requests.
asyncResult.RemoveAsyncWeb(operation);
// Complete the request and get the video feed.
Feed<Video> feed = request.End(result);
// If the operation completed successfully, set the browsable to true.
obj.Browsable = true;
// Set the response HTTP code.
obj.HttpCode = (int)(result as AsyncWebResult).Response.StatusCode;
// Return the result.
return (feed.FailuresAtom.Count == 0) && (feed.FailuresEntry.Count == 0) ? CrawlResult.Success : CrawlResult.Warning;
}
catch (WebException exception)
{
if (exception.Status == WebExceptionStatus.RequestCanceled)
{
return CrawlResult.Canceled;
}
else
{
// If the operation failed with a web exception, set the browsable to false.
obj.Browsable = false;
// Set the response HTTP code.
obj.HttpCode = (int)(exception.Response as HttpWebResponse).StatusCode;
// Return the result.
return CrawlResult.Fail;
}
}
catch (Exception)
{
// If the operation failed with a web exception, set the browsable to false.
obj.Browsable = false;
// Set the response HTTP code to null.
obj.HttpCode = null;
// Return the result.
return CrawlResult.Fail;
}
}
/// <summary>
/// Sets whether the specified standard feed is selected.
/// </summary>
/// <param name="feed">The standard feed.</param>
/// <param name="selected"><b>True</b> if the standard feed is selected, <b>false</b> otherwise.</param>
public void SetFeedSelected(YouTubeStandardFeed feed, bool selected)
{
DotNetApi.Windows.RegistryExtensions.SetBoolean(this.crawler.Config.SpidersConfigPath + @"\StandardFeeds", feed.ToString(), selected);
}
/// <summary>
/// Gets whether the specified standard feed is selected.
/// </summary>
/// <param name="feed">The standard feed.</param>
/// <returns><b>True</b> if the standard feed is selected, <b>false</b> otherwise.</returns>
public bool GetFeedSelected(YouTubeStandardFeed feed)
{
return DotNetApi.Windows.RegistryExtensions.GetBoolean(this.crawler.Config.SpidersConfigPath + @"\StandardFeeds", feed.ToString(), false);
}
/// <summary>
/// Computes the feed key for a set of feed parameters.
/// </summary>
/// <param name="feedId">The feed ID.</param>
/// <param name="timeId">The time ID.</param>
/// <param name="category">The category.</param>
/// <param name="regionId">The region ID.</param>
/// <returns>The feed key.</returns>
public string EncodeFeedKey(YouTubeStandardFeed feedId, YouTubeTimeId timeId, string category, string regionId)
{
return "{0}.{1}.{2}.{3}".FormatWith(
(int)feedId,
(int)timeId,
category != null ? category : string.Empty,
regionId != null ? regionId : string.Empty);
}
