Libation/REFERENCE.txt

-- begin AUDIBLE DETAILS ---------------------------------------------------------------------------------------------------------------------

alternate book id (eg BK_RAND_006061) is called 'sku' , 'sku_lite' , 'prod_id' , 'product_id' in different parts of the site

-- end AUDIBLE DETAILS ---------------------------------------------------------------------------------------------------------------------

-- begin DOTNET CORE DI ---------------------------------------------------------------------------------------------------------------------
from: https://andrewlock.net/using-dependency-injection-in-a-net-core-console-application/

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

public class Program
{
    public static void Main(string[] args)
    {
        //setup our DI
        var serviceProvider = new ServiceCollection()
            .AddLogging()
            .AddSingleton<IFooService, FooService>()
            .AddSingleton<IBarService, BarService>()
            .BuildServiceProvider();

        //configure console logging
        serviceProvider
            .GetService<ILoggerFactory>()
            .AddConsole(LogLevel.Debug);

        var logger = serviceProvider.GetService<ILoggerFactory>().CreateLogger<Program>();
        logger.LogDebug("Starting application");

        //do the actual work here
        var bar = serviceProvider.GetService<IBarService>();
        bar.DoSomeRealWork();

        logger.LogDebug("All done!");
    }
}
-- end DOTNET CORE DI ---------------------------------------------------------------------------------------------------------------------

-- begin SOLUTION LAYOUT ---------------------------------------------------------------------------------------------------------------------
core libraries
  extend Standard Libraries
  additional simple libraries for general purpose programming
utils: domain ignorant
domain: biz logic
  db ignorant
  db, domain objects
  db aware
    incl non-db persistence. unless it needs to be tied into a db intercepter
    all user-provided data must be backed up to json
  utilities: domain aware
application

do NOT combine jsons for
- audible-scraped persistence: library, book details
- libation-generated persistence: FilePaths.json
- user-defined persistence: BookTags.json
-- end SOLUTION LAYOUT ---------------------------------------------------------------------------------------------------------------------

-- begin EF CORE ---------------------------------------------------------------------------------------------------------------------
transaction notes
-----------------
// https://msdn.microsoft.com/en-us/data/dn456843.aspx
// Rollback is called by transaction Dispose(). No need to call it explicitly
  using (var dbContext = new LibationContext())
  using (var dbContextTransaction = dbContext.Database.BeginTransaction())
  {
      refreshAction(dbContext, productItems);
      dbContext.SaveChanges();
      dbContextTransaction.Commit();
  }

aggregate root is transactional boundary
  // //context.Database.CurrentTransaction
  //var dbTransaction = Microsoft.EntityFrameworkCore.Storage.DbContextTransactionExtensions.GetDbTransaction(context.Database.CurrentTransaction);
  // // test with and without : using (TransactionScope scope = new TransactionScope())
  //System.Transactions.Transaction.Current.TransactionCompleted += (sender, e) => { };
  // also : https://docs.microsoft.com/en-us/dotnet/api/system.transactions.transaction.enlistvolatile

pattern when using 1 db context per form
    public Ctor()
    {
        InitializeComponent();
        // dispose context here only. DO NOT dispose in OnParentChanged(). parent form will call dispose after this one has been switched.
        // disposing context prematurely can result in:
        //   The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.
        this.Disposed += (_, __) => context?.Dispose();
    }
-- end EF CORE ---------------------------------------------------------------------------------------------------------------------

-- begin ASYNC/AWAIT ---------------------------------------------------------------------------------------------------------------------
Using Async and Await to update the UI Thread <20> Stephen Haunts { Coding in the Trenches }
https://stephenhaunts.com/2014/10/14/using-async-and-await-to-update-the-ui-thread/

Using Async and Await to update the UI Thread Part 2 <20> Stephen Haunts { Coding in the Trenches }
https://stephenhaunts.com/2014/10/16/using-async-and-await-to-update-the-ui-thread-part-2/

Simple Async Await Example for Asynchronous Programming <20> Stephen Haunts { Coding in the Trenches }
https://stephenhaunts.com/2014/10/10/simple-async-await-example-for-asynchronous-programming/

Async and Await -- Stephen Cleary's famous intro
https://blog.stephencleary.com/2012/02/async-and-await.html

Async-Await - Best Practices in Asynchronous Programming -- Stephen Cleary
https://msdn.microsoft.com/en-us/magazine/jj991977.aspx


ASYNC PARALLELISM -- pre C# 8
=================
private async Task WaitThreeSeconds(int param)
{
    Console.WriteLine($"{param} started ------ ({DateTime.Now:hh:mm:ss}) ---");
    await Task.Delay(3000);
    Console.WriteLine($"{ param} finished ------({ DateTime.Now:hh:mm: ss}) ---");
}
///////////////////////////////////////////////////////////////////////
// SERIAL CODE
var listOfInts = new List<int>() { 1, 2, 3 };
foreach (var integer in listOfInts)
    await WaitThreeSeconds(integer);
// SERIAL RESULTS
1 started ------ (00:00:40) ---
1 finished ------(00:00: 43) ---
2 started ------ (00:00:43) ---
2 finished ------(00:00: 46) ---
3 started ------ (00:00:46) ---
2 finished ------(00:00: 49) ---
///////////////////////////////////////////////////////////////////////
// PARALLEL CODE
var listOfInts = new List<int>() { 1, 2, 3 };
var tasks = new List<Task>();
foreach (var integer in listOfInts)
    tasks.Add(WaitThreeSeconds(integer));
await Task.WhenAll(tasks);
// PARALLEL RESULTS
1 started ------ (00:00:02) ---
2 started ------ (00:00:02) ---
3 started ------ (00:00:02) ---
3 finished ------(00:00: 05) ---
2 finished ------(00:00: 05) ---
1 finished ------(00:00: 05) ---
///////////////////////////////////////////////////////////////////////
// similar. note that await IS NOT being used in the top method calls. TASKS are returned. those tasks are later awaited in parallel
var catTask = FeedCatAsync();
var houseTask = SellHouseAsync();
var carTask = BuyCarAsync();

await Task.WhenAll(catTask, houseTask, carTask).ConfigureAwait(false);

var cat = await catTask;
var house = await houseTask;
var car = await carTask;
-- end ASYNC/AWAIT ---------------------------------------------------------------------------------------------------------------------