private static void ShowSuccessMessage(Book book)
{
var message = String.Format("\"{0}\" successfully saved.",
book.Title);
Toaster.ShowToast("New Book saved",
message);
}
public bool Exists(Book book)
{
using (var store = ObjectStore.GetInstance<Book>())
{
return store.LoadSingle(x => x.Equals(book)) != null;
}
}
public void Add(Book book)
{
using (var store = ObjectStore.GetInstance<Book>())
{
store.SaveOnSubmit(book);
}
}
private Result NewSuccessResult(Book book)
{
return new Result
{
Book = book,
Success = true,
ErrorMessage = String.Empty
};
}
public async void Execute(object parameter)
{
var book = new Book
{
Author = _mainViewModel.Author.Trim(),
Title = _mainViewModel.Title.Trim(),
Isbn = _mainViewModel.Isbn.Trim()
};
try
{
var result = await SubmitService.SubmitAsync(book);
if (result.Success)
{
ShowSuccessMessage(book);
await _mainViewModel.RetryService.RetryPublishAsync();
}
else
{
// an exception occurred on the server;
// ErrorCode 1 means duplicate
// anithing else means we have to retry
if (result.ErrorCode > 1)
{
throw new Exception(
string.Format("Server Error: {0}({1})",
result.ErrorMessage,
result.ErrorCode));
}
throw new BookExistsException();
}
}
catch (BookExistsException)
{
ShowBookExistsMessage(book);
}
catch (Exception)
{
// catch all exceptions to add the book to
// the retry service in case of an error
if (_mainViewModel.RetryService.Exists(book))
{
ShowBookExistsMessage(book);
}
else
{
_mainViewModel.RetryService.Add(book);
ShowBooksSavedLocallyMessage(book);
}
}
_mainViewModel.ClearForm.Execute(null);
}
private Result NewFailResult(Book book, Exception ex)
{
return new Result
{
Book = book,
Success = false,
ErrorCode = 2,
ErrorMessage = ex.Message
};
}
private Result NewDuplicateResult(Book book)
{
return new Result
{
Book = book,
Success = false,
ErrorCode = 1,
ErrorMessage = String.Format("Book \"{0}\" allready exists", book.Title)
};
}
public static async Task<Result> SubmitAsync(Book book)
{
var client = new HttpClient
{
BaseAddress = new Uri("http://localhost:33300")
};
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
var response = await client.PostAsJsonAsync("/api/Books", book);
response.EnsureSuccessStatusCode(); // throws an exception on error
var result = JsonConvert.DeserializeObject<Result>(
await response.Content.ReadAsStringAsync());
return result;
}
// POST api/books
public Result Post(Book book)
{
using (var store = ObjectStore.GetInstance<Book>())
{
try
{
if (BookExists(store, book))
{
// tell us if the book already exists
return NewDuplicateResult(book);
}
store.SaveOnSubmit(book);
return NewSuccessResult(book);
}
catch (Exception ex)
{
// tell us if something unexpected happened
return NewFailResult(book, ex);
}
}
}
private bool BookExists(IObjectStore<Book> store, Book book)
{
var existing = store.LoadSingle(x => x.Equals(book));
return existing != null;
}
private static void ShowBookExistsMessage(Book book)
{
var message = String.Format("\"{0}\" allready exists.",
book.Title);
Toaster.ShowToast("New Book exists!",
message);
}
private static void ShowBooksSavedLocallyMessage(Book book)
{
var message = String.Format("\"{0}\" saved locally.",
book.Title);
Toaster.ShowToast("New Book locally saved",
message);
}