/// <summary>
/// Returns a list of recordings scraped from the URLS provided
/// by the course instance object.</summary>
/// <param name="document"></param>
/// <returns></returns>
public List <Recording> GetRecordings(CourseInstance course, IProgress <Double> callback = null)
{
var recordingList = new List <Recording>();
// Retrieve recordings from each page associated with the given course instance
for (var i = 0; i < course.PageLinks.Count(); i++)
{
var link = BASE_URL + course.PageLinks[i];
HtmlDocument document = LoadDocument(link);
// TODO: Figure out what to do on document load failure
if (document != null)
{
// Retrieve nodes containing recording data
var recordingNodes = document.DocumentNode.SelectNodes(
"//table[@class='mainindex']");
if (recordingNodes != null)
{
// Retrieve information from each node
foreach (var node in recordingNodes)
{
var headingNode = node.SelectSingleNode(
".//tr[@class='sectionHeading']//h3");
// Retrieve timestamp
var timestamp = headingNode.InnerText;
timestamp = Regex.Replace(timestamp, " ", "");
timestamp = Regex.Replace(timestamp, @"\s+", " ").Trim();
var recordingDate = DateTime.ParseExact(
timestamp, "dd MMM yyyy - HH:mm",
CultureInfo.CurrentCulture);
// Retrieve recording ID
var recordingID = Convert.ToInt32(
headingNode.SelectSingleNode(".//a")
.GetAttributeValue("id", 0));
// Retrieve recording duration
var duration = node.SelectSingleNode(
".//tr[@class='sectionHeading']/td[2]").InnerText.Trim();
// Construct recording instance
var recording = new Recording(recordingID,
recordingDate, duration);
// Retrieve list of file formats
var formatList = GetRecordingFormats(node);
formatList.ForEach(f => recording.Formats.Add(f));
// Add recording to course instance
recordingList.Add(recording);
}
}
// Report progress
if (callback != null)
{
lock (callback)
{
callback.Report((double)i / course.PageLinks.Count() * 100);
}
}
}
}
return(recordingList);
}
/// <summary>
/// Attempts to load the Lectopia recording list with the given ID. On a successful load,
/// this method will parse the contents of the page and append the parsed data to the model
/// in a form of a course instance object.
/// </summary>
/// <param name="id"></param>
public CourseInstance ReadCourseInformation(int id)
{
String URL = RECORDINGS_URL + id;
// Check if given URL points to a valid listing
// If list loaded successfully, load document
HtmlDocument document = null;
try
{
document = LoadDocument(URL);
}
// In event of a connection timeout, add attempted URL to collection for a later retry
catch (WebException)
{
// TODO: Log error
lock (FailedReads)
{
FailedReads.Add(id);
}
}
// If document loaded successfully, parse contents
if (document != null)
{
// Retrieve subject title
var title = document.DocumentNode.SelectSingleNode(
"//table[@id='header']//h2").InnerText.Trim();
// Retrieve date of last recording
DateTime?lastUpdated = null;
var lastRecorded = document.DocumentNode.SelectSingleNode(
"//table[@class='mainindex'][1]//tr[@class='sectionHeading']//h3");
if (lastRecorded != null)
{
var timestamp = lastRecorded.InnerText;
timestamp = Regex.Replace(timestamp, " ", "");
timestamp = Regex.Replace(timestamp, @"\s+", " ").Trim();
lastUpdated = DateTime.ParseExact(
timestamp, "dd MMM yyyy - HH:mm",
CultureInfo.CurrentCulture);
}
// Construct course instance
var course = new CourseInstance(id, title, lastUpdated);
course.PageLinks.Add(TruncatePageURL(URL));
// Extract page links
var pageNodes = document.DocumentNode.SelectNodes(
"(//td[@class='noNesting'])[1]/a");
if (pageNodes != null)
{
var pageLinks = from a in pageNodes
select TruncatePageURL(BASE_URL
+ a.GetAttributeValue("href", ""));
course.PageLinks.AddRange(pageLinks);
}
// Return constructed instance
return(course);
}
return(null);
}
