public VideoDownloadInfo(VideoAvailabilityEnum availability, string contentId, string contentTitle, string errorMessage, List <VideoMetadata> videos)
{
Availability = availability;
ContentId = contentId;
ContentTitle = contentTitle;
ErrorMessage = errorMessage;
Videos = (videos?.Count ?? 0) > 0 ? new List <VideoMetadata>(videos) : null;
}
// Retrieves the available download urls by decoding the video info DOM for the 'contentId' to parse for itags.
public VideoDownloadInfo GetVideoDownloadInfo(string contentId, string contentTitle, string dom)
{
const string _responseError = "&errorcode";
const string _responseErrorCode = "&errorcode=150";
const string _responsePurchase = "&requires_purchase";
const string _url = "url=";
const string _streamMapPattern = "(?<=url_encoded_fmt_stream_map=).*";
if (string.IsNullOrEmpty(contentId))
{
return(new VideoDownloadInfo(VideoAvailabilityEnum.NotAvailable, null, contentTitle, "Missing content id.", null));
}
if (string.IsNullOrEmpty(contentTitle))
{
return(new VideoDownloadInfo(VideoAvailabilityEnum.NotAvailable, contentId, null, "Missing content title.", null));
}
if (string.IsNullOrEmpty(dom))
{
return(new VideoDownloadInfo(VideoAvailabilityEnum.NotAvailable, contentId, contentTitle, "Missing dom.", null));
}
// Decode pass 1.
dom = WebUtility.UrlDecode(dom);
// Check for errors and specific messages.
if (dom.Contains(_responseError) || dom.Contains(_responsePurchase))
{
string errorMessage = string.Empty;
VideoAvailabilityEnum errorStatus = VideoAvailabilityEnum.NotAvailable;
if (dom.Contains(_responseErrorCode))
{
errorStatus = VideoAvailabilityEnum.ErrorCode;
errorMessage = "YouTube video info response contains errorcode 150.";
}
else if (_responseError.Contains(_responsePurchase))
{
errorStatus = VideoAvailabilityEnum.RequiresPurchase;
errorMessage = "YouTube content requires purchase.";
}
else
{
errorStatus = VideoAvailabilityEnum.ErrorCode;
errorMessage = "The dom contains an error in the response.";
}
return(new VideoDownloadInfo(errorStatus, contentId, contentTitle, errorMessage, null));
}
// Get everything after "url_encoded_fmt_stream_map=".
dom = Regex.Match(dom, _streamMapPattern).Value;
// Decode pass 2.
dom = WebUtility.UrlDecode(dom);
// Split.
string[] responseUrls = Regex.Split(dom, _url);
// Clean up the URLs and place them in a new list.
var data = new List <VideoMetadata>(responseUrls.Length);
foreach (var response in responseUrls)
{
string url = RemoveQueryParameters(response);
// Check the results after removing unnecessary query parameters and gather the metadata for the url.
if (!string.IsNullOrEmpty(url))
{
if (MediaQualityEnumHelpers.TryParseUrlForItag(url, out string itag))
{
if (MediaQualityEnumHelpers.TryMapItagToEnum(itag, out MediaQualityEnum quality))
{
data.Add(new VideoMetadata(contentId, contentTitle, quality, url)); // Hope
}
}
}
}
// Check if there are urls.
if (data.Count < 1)
{
return(new VideoDownloadInfo(VideoAvailabilityEnum.NotAvailable, contentId, contentTitle, "Download urls are not available.", null));
}
// Lower the capacity of the metadata list.
data.TrimExcess();
return(new VideoDownloadInfo(
VideoAvailabilityEnum.Available,
contentId,
contentTitle,
null,
data));
}
