/// <summary>
/// Gets the weather data.
/// </summary>
private static void GetWeatherData()
{
Debug.Assert(Sources != null && Sources.Any(), "Weather data sources cannot be null or empty.");
foreach (WeatherDataSources source in Sources)
{
try
{
// Validate the format of the URL
Uri sourceUri;
if (Uri.TryCreate(source.Url, UriKind.Absolute, out sourceUri) && sourceUri.Scheme == Uri.UriSchemeHttp)
{
using (System.Net.WebClient client = new System.Net.WebClient())
{
string html = client.DownloadString(sourceUri);
if (!string.IsNullOrWhiteSpace(html))
{
// Get the first line of HTML
HtmlDocument = new HtmlAgilityPack.HtmlDocument();
HtmlDocument.LoadHtml(html);
DataParser parser = new DataParser();
// TODO: Evaluate whether to use an enumerator here instead of strings
switch (source.Airport.ToLowerInvariant())
{
case "cynr":
parser.SetParseStrategy(new CynrParse());
break;
case "cet2":
parser.SetParseStrategy(new Cet2Parse());
break;
case "cfg6":
parser.SetParseStrategy(new Cfg6Parse());
break;
case "crl4":
parser.SetParseStrategy(new Crl4Parse());
break;
default:
throw new InvalidOperationException("Invalid airport code specified in the configuration file.");
}
string data = parser.Parse();
// Parse and store the data
if (!string.IsNullOrWhiteSpace(data))
{
// Does the string look as we expect?
const string pattern = @"^(METAR|SPECI)\s\w{4}\s\d{6}Z(.*)$";
System.Text.RegularExpressions.Regex expression = new System.Text.RegularExpressions.Regex(pattern, System.Text.RegularExpressions.RegexOptions.Compiled);
bool isValidData = expression.IsMatch(data);
if (!isValidData)
{
throw new Exception(string.Format("Parsed data returned by {0} is an invalid data format: {1}", sourceUri, data));
}
ParseWeatherData(data);
}
}
else
{
// The HTML was blank, so there's nothing else we can do
throw new Exception(string.Format("The HTML document returned by a configured URL ({0}) is empty.", sourceUri));
}
}
}
else
{
// We had trouble creating the URL using configuration file entries
throw new UriFormatException(string.Format("The system was unable to parse a URL ({0}) in the configuration file.", sourceUri));
}
}
catch (Exception x)
{
WriteToEventApplicationLog(x);
SendMail(x.Message);
}
}
}