public IHtmlParser CreateParserFromSourceUrl(string url)
{
var htmlParser = default(IHtmlParser);
//if the url has already been downloaded once we store it in memory for this instance of the default web services.
//helps avoid multiple downloads of a file that likely hasn't changed in this short time span.
if (!_cachedUrls.ContainsKey(url))
{
try
{
string pageSource = _pageDownloader.DownloadPageSource(new Uri(url), _webClientProvider);
_cachedUrls[url] = new CacheableUrlResponse
{
PageSource = pageSource
};
htmlParser = _htmlParserProvider.Create(_cachedUrls[url].PageSource);
}
catch (PageNotFoundException ex)
{
var cacheableResponse = new CacheableUrlResponse
{
PageSource = string.Empty,
ResponseException = ex
};
_cachedUrls[url] = cacheableResponse;
throw _cachedUrls[url].ResponseException;
}
}
else
{
var cachedValue = _cachedUrls[url];
if (cachedValue.ResponseException != null)
{
throw cachedValue.ResponseException;
}
else
{
htmlParser = _htmlParserProvider.Create(cachedValue.PageSource);
}
}
return(htmlParser);
}
