private async Task <HttpResponseMessage> AskForBook(IBookSite bookSite, string isbn)
{
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.Add("User-Agent", "User-Agent-Here");
return(await client.GetAsync(bookSite.SearchUri + isbn));
}
}
private async Task <BookPriceObject?> GetBookData(IBookSite bookSite, string isbn)
{
var htmlDocument = new HtmlDocument();
var response = await this.AskForBook(bookSite, isbn);
htmlDocument.LoadHtml(await response.Content.ReadAsStringAsync());
var nodeWithValue = htmlDocument.DocumentNode.SelectNodes(bookSite.XPath)?.FirstOrDefault();
try
{
return(bookSite.GetValueFromHtmlNode(nodeWithValue));
}
catch (ArgumentNullException)
{
Console.WriteLine($"Could not find book with: {isbn} in {bookSite.GetType().Name}");
return(null);
}
catch (NullReferenceException)
{
Console.WriteLine($"Could not find book with: {isbn} in {bookSite.GetType().Name}");
return(null);
}
}
