Libation/FileLiberator/UNTESTED/DownloadableBase.cs
2019-12-05 15:55:46 -05:00

62 lines
1.8 KiB
C#

using System;
using System.Threading.Tasks;
using DataLayer;
using Dinah.Core.ErrorHandling;
using Dinah.Core.Net.Http;
namespace FileLiberator
{
public abstract class DownloadableBase : IDownloadable
{
public event EventHandler<LibraryBook> Begin;
public event EventHandler<LibraryBook> Completed;
public event EventHandler<string> DownloadBegin;
public event EventHandler<DownloadProgress> DownloadProgressChanged;
public event EventHandler<string> DownloadCompleted;
public event EventHandler<string> StatusUpdate;
protected void Invoke_StatusUpdate(string message) => StatusUpdate?.Invoke(this, message);
public abstract bool Validate(LibraryBook libraryBook);
public abstract Task<StatusHandler> ProcessItemAsync(LibraryBook libraryBook);
// do NOT use ConfigureAwait(false) on ProcessAsync()
// often calls events which prints to forms in the UI context
public async Task<StatusHandler> ProcessAsync(LibraryBook libraryBook)
{
Begin?.Invoke(this, libraryBook);
try
{
return await ProcessItemAsync(libraryBook);
}
finally
{
Completed?.Invoke(this, libraryBook);
}
}
protected async Task<string> PerformDownloadAsync(string proposedDownloadFilePath, Func<Progress<DownloadProgress>, Task<string>> func)
{
var progress = new Progress<DownloadProgress>();
progress.ProgressChanged += (_, e) => DownloadProgressChanged?.Invoke(this, e);
DownloadBegin?.Invoke(this, proposedDownloadFilePath);
try
{
var result = await func(progress);
StatusUpdate?.Invoke(this, result);
return result;
}
finally
{
DownloadCompleted?.Invoke(this, proposedDownloadFilePath);
}
}
}
}