wan24-Core 1.8.1

wan24-Core

This core library contains some .NET extensions:

• Bootstrapping
• Disposable base class for disposable types, which supports asynchronous disposing
  • Dispose attribute for fields/properties which should be disposed automatic when disposing
• Type helper (type loading)
• Secure byte array, which clears its contents when disposing
• Pool rented array as disposable object
• Byte array extensions
  • Endian conversion
  • Bit-converter (endian-safe)
  • UTF-8 string decoding
  • Clearing
• Array helper extensions
  • Offset/length validation
• Array pool extensions
  • Renting a cleared array
• Enumerable extensions
  • Combine enumerables
  • Chunk enumerables
• Reflection extensions
  • Automatic parameter extension when invoking a method (with DI support)
  • Synchronous/asynchronous method invokation
  • Automatic constructor invokation using a given parameter set (with DI support)
  • Nullability detection
• Delegate extensions
  • Delegate list invokation (with or without return values, with DI support)
  • Asynchronous delegate list invokation (with or without return values, with DI support)
• Task extensions
  • Result getting of a generic task
  • Asynchronous task list awaiting
  • Shortcuts for await configurations
• DI helper
  • Service provider adoption
  • DI object factory delegates
  • Asynchronous DI object factory delegates
• Enumeration extensions
  • Get enumeration value display string from DisplayTextAttribute or using ToString (fallback)
  • Remove flags of a mixed enumeration value
  • Get only flags of a mixed enumeration value
  • Value validation
• Number extensions
  • Determine if a type is a number
  • Determine if a number type is unsigned
  • Bit-converter (endian-safe)
  • Determine if a number (or any IComparable) is within a range
• Numeric bitwise extensions
• Collection extensions
  • Add a range of items
• JSON helper
  • Exchangeable JSON encoder/decoder delegates (using System.Text.Json per default)
• JSON extensions
  • Encode an object
  • Decode from a type
  • Decode a string
• Object extensions
  • Type conversion
  • Determine if a value is within a list of values
• String extensions
  • Get UTF-8 bytes
• Generic helper
  • Determine if two generic values are equal
  • Determine if a value is null
  • Determine if a value is default
  • Determine if a value is null or default
• DateTime extensions
  • Determine if a time is within a range
  • Determine if a time matches a reference time plus/minus an offset
  • Apply an offset to a time base on a reference time
• Queue worker (for actions and/or items)
• Parallel queue worker (for actions and/or items)
• ParallelAsync implementation
• Base class for a hosted worker, which implements the IHostedService interface (timed or permanent running)
• EventThrottle for throttling event handler calls
• ProcessThrottle for throttling a processing channel
• OrderedDictionary<tKey, tValue> is used for working with indexed key/value pairs
• Timeout will count down and raise an event, if not reset before reaching the timeout
• ILogger support
• IChangeToken support using ChangeCallback
• Hierarchic configuration using OverrideableConfig

How to get it

This library is available as NuGet package "wan24-Core".

Bootstrapping

The Bootstrapper.Async method calls all static methods having the BootstrapperAttribute. In order to be able to find the methods, it's required to add the BootstrapperAttribute to the assembly.

You may also ad the BootstrapperAttribute to a type and/or the bootstrapper method, in case the assembly contains multiple of them. In the assembly attribute you need to set ScanClasses and/or ScanMethods to true in order to perform a deep scanning during bootstrapping for performance reasons.

The bootstrapper methods may consume parameters which are available from the DI helper. The method may be synchronous or asynchronous. The method can't be defined in a generic class, and it can't be generic itself.

[assembly:Bootstrapper(typeof(YourBootstrapper),nameof(YourBootstrapper.BootstrapperMethod))]

public static class YourBootstrapper
{
    public static async Task BootstrapperMethod()
    {
        // Perform your bootstrapping here
    }
}

// Call the bootstrapper somewhere in your apps initialization code
await Bootstrap.Async();

The BootstrapperAttribute can be initialized with a numeric priority. The bootstrapper will order the found bootstrapping methods by priority, where the one with the highest number will be executed first (assembly and type priorities count, too). At last there's a assembly location, type and method name sorting. Bootstrapper methods will be executed sequential.

If you give a type and a method name to the assembly BootstrapperAttribute, you won't need to add the attribute to the type and the method.

During bootstrapping, the cancellation token which was given to the Bootstrap.Async method, can be injected to a bootstrappers method parameters.

After that bootstrapping was done, the Bootstrap.AsyncBootstrapper will be called. At last the Bootstrap.OnBootstrap event will be raised.

During bootstrapping the Bootstrap.IsBooting property is true. After bootstrapping the Bootstrap.DidBoot property is true.

The bootstrapper will load all referenced assemblies. If you load an assembly later, it'll be bootstrapped automatic and added to the TypeHelper singleton instance.

Type helper

If you use the TypeHelper.AddTypes method, the unknown assemblies of the added types will be added as searchable assemblies automatic.

You may attach to the TypeHelper.OnLoadType event for handling requests more dynamic.

The TypeHelper.GetType method will try Type.GetType first and fall back to the helper, if no type was found.

DI helper

In order to make DI (dependency injection) working, you need to

• set a DiHelper.ServiceProvider and/or
• add DiHelper.(Async)ObjectFactories

The DiHelper.GetDiObjectAsync method will try to resolve the request synchronous, first. But the DiHelper.GetDiObject won't try asynchronous object factories.

Mixed enumeration value

A mixed enumeration contains X bits enumeration values, and Y bits flags:

[Flags]
public enum MixedEnum : int
{
    None = 0,
    Value1 = 1,
    Value2 = 2,
    Value3 = 3,
    ...
    Flag1 = 1 << 8,
    Flag2 = 1 << 9,
    FLAGS = Flag1 | Flag2 // Required to identify flags
}

The FLAGS value helps these extension methods to handle flag values:

MixedEnum value = MixedEnum.Value1 | MixedEnum.Flag1,
    valueOnly = value.RemoveFlags(),// == MixedEnum.Value1
    flagsOnly = value.OnlyFlags();// == MixedEnum.Flag1

Unsafe code

The library uses unsafe code. If you don't want/need that, you can compile the library with the NO_UNSAFE compiler constant to disable any unsafe operation. Remember to unset the unsafe compiler option, too!

Disposable base class

The DisposableBase implements the IDisposable and IAsyncDisposable interfaces. It provides some helpers and events, and also the DisposeAttribute, which can be applied to fields and properties which you wish to dispose automatic when disposing.

When your type derives from the DisposableBase, you'll need to implement the abstract Dispose method:

protected override Dispose(bool disposing)
{
    // Your dispose logic here
}

There are measures to avoid that this method is being called twice.

To implement custom asynchronous disposing:

protected override async Task DisposeCore()
{
    // Your dispose logic here
}

In order to make the DisposeAttribute working, you have to call the protected method DisposeAttributes or DisposeAttributesAsync.

The IsDisposing property value will be true as soon as the disposing process started, and it will never become false again. The IsDisposed property value will be true as soon as the disposing process did finish.

Queue worker

using QueueWorker worker = new();
await worker.EnqueueAsync((ct) =>
{
    // Do any background action here
});

The QueueWorker class can be extended as you need it.

The ParallelQueueWorker requires a number of threads in the constructor, which defines the degree of parallelism, in which enqueued tasks will be processed.

Queue item worker

using QueueItemWorker<ItemType> worker = new();
await worker.EnqueueAsync(new ItemType());

The QueueItemWorker<T> class can be extended as you need it.

The ParallelItemQueueWorker<T> requires a number of threads in the constructor, which defines the degree of parallelism, in which enqueued items will be processed.

ParallelAsync

Using the .NET parallel implementation it's not possible to invoke asynchronous item handlers. For this you can use the ParallelAsync.ForEachAsync method, which uses a parallel item queue worker in the background for asynchronous processing.

Hosted worker

public class YourHostedWorker : HostedWorkerBase
{
    public YourHostedWorker() : base() { }

    protected override async Task WorkerAsync()
    {
        // Perform the service actions here
    }
}

The hosted worker implements the IHostedService interface and can be extended as you need it.

Timed hosted worker

public class YourHostedWorker : TimedHostedWorkerBase
{
    public YourHostedWorker() : base(interval: 500) { }

    protected override async Task WorkerAsync()
    {
        // Perform the service actions here
    }
}

This example uses a 500ms timer. Based on the defined timer type, the interval will be processed in different ways:

• Default: Next worker run is now plus the interval (used by default)
• Exact: Next worker run is now plus the interval minus the processing duration (used, if the start time of the processing is important)
• ExactCatchingUp: As Exact, but catching up missing processing runs without delay, if a worker run duration exceeds the interval (used, if the number of worker runs is important)

Using the SetTimerAsync method you can change the timer settings at any time. If you give the nextRun parameter, you may set a fixed next run time (which won't effect the given interval, but just force the service to run at a specific time for the next time).

NOTE: The nextRun parameter will also force the service to (re)start!

By setting the property RunOnce to true, the service will stop after running the worker once. In combination with the SetTimerAsync parameter nextRun you can execute the worker at a specific time once.

The hosted worker implements the IHostedService interface and can be extended as you need it.

EventThrottle

public class YourType : DisposableBase
{
    protected readonly YourEventThrottle EventThrottle;

    public YourType() : base() => EventThrottle = new(this);

    // This method will raise the OnEvent
    public void AnyMethod()
    {
        RaiseOnEventThrottled();
    }

    protected override Dispose(bool disposing) => EventThrottle.Dispose();

    // Delegate for OnEvent
    public delegate void YourTypeEvent_Delegate();
    // Event to throttle
    public event YourTypeEvent_Delegate? OnEvent;
    // Raise the OnEvent using the event throttle
    protected void RaiseOnEventThrottled() => EventThrottle.Raise();
    // Finally let the event handlers process the event
    protected void RaiseOnEvent() => OnEvent?.Invoke();

    // Event throttle implementation
    public class YourEventThrottle : EventThrottle
    {
        // Throttle the event handling down to max. one handling per 300ms
        public YourEventThrottle(YourType instance) : base(timeout: 300) => Instance = instance;

        public YourType Instance { get; }

        protected override HandleEvent(DateTime raised, int raisedCount)
        {
            Instance.RaiseOnEvent();
        }
    }
}

If AnyMethod is being called, the event will be forwarded to the event throttle, which decides to throttle or raise the event. If AnyMethod was called three times within 300ms, the first call will be executed in realtime, while the 2nd and the 3rd call will be sqashed and executed once 300ms after the 1st call was processed.

This example assumes you're working with a real event - but you may throttle any event (which may not be a real event) using throttling logic.

ProcessThrottle

public class YourProcessThrottle : ProcessThrottle
{
    // Throttle to processing one object per second
    public YourProcessThrottle() : base(limit: 1, timeout: 1000) { }

    // Processing API using a timeout
    public async Task<int> ProcessAsync(Memory<bool> items, TimeSpan timeout)
        => await ProcessAsync(items.Length, (count) => 
        {
            await Task.Yield();
            Span<bool> toProcess = items.Span[..count];
            items = items[count..];
            // Process toProcess
        }, timeout);

    // Processing API using a cancellation token
    public async Task<int> ProcessAsync(Memory<bool> items, CancellationToken token = default)
        => await ProcessAsync(items.Length, (count) => 
        {
            await Task.Yield();
            Span<bool> toProcess = items.Span[..count];
            items = items[count..];
            // Process toProcess
        }, token);
}

The example will throttle the processing to a maximum of one object per second. Multiple threads may call ProcessAsync concurrent - processing will be organized thread-safe.

The return value of ProcessAsync is the number of objects processed until timeout or cancelled.

The processing delegate shouldn't care about the timeout or if cancelled and just process the given number of objects.

NOTE: A usage gap will slide the throttling timer. Example:

The timeout was set to 3 objects per 100ms. Now processing goes like this:

• First processed object on 0ms will activate the throttling timeout
• Next processed object on 10ms will increase the object throttling counter
• Next processed object on 110ms will reset the throttling timeout and counter (the usage gap of 100ms does exceed the timeout)
• Next 2 processed objects on 120ms will activate the throttle
• Next object will have to wait until the throttle was released
• The throttle will be released on 210ms, which allows the last object to be processed now

In short words: The throttle timer will not reset in an fixed interval, but the interval starts when processing items.

Change token

Implement by extending ChangeToken:

public class YourObservableType : ChangeToken
{
    public YourObservableType() : base()
    {
        ChangeIdentifier = () => HasChanged;
    }

    public bool HasChanged => ...;// Return if the object was changed

    public void ChangeAction()
    {
        // Perform changes
        InvokeCallbacks();
    }
}

Or by using a ChangeToken instance:

public class YourObservableType : IChangeToken
{
    public readonly ChangeToken ChangeToken;

    public YourObservableType() => ChangeToken = new(() => HasChanged);

    public bool HasChanged => ...;// Return if the object was changed

    public void ChangeAction()
    {
        // Perform changes
        ChangeToken.InvokeCallbacks();
    }

    // Implement the IChangeToken interface using our ChangeToken instance

    bool IChangeToken.HasChanged => ChangeToken.HasChanged;

    bool IChangeToken.ActiveChangeCallbacks => ChangeToken.ActiveChangeCallbacks;

    IDisposable IChangeToken.RegisterChangeCallback(Action<object?> callback, object? state)
        => ChangeToken.RegisterChangeCallback(callback, state);
}

Hierarchic configuration

Assume this configuration hierarchy:

In code:

public sealed class Config : OverrideableConfig<Config>
{
    public Config() : base()
    {
        SubConfig = new(this, new(this));// User values
        InitProperties();
    }

    private Config(Config parent, Config? sub = null) : base(parent)
    {
        if(sub != null)
        {
            SubConfig = sub;
            sub.ParentConfig = this;
            sub.SubConfig = new(sub);// Administrator values
        }
        InitProperties();
    }

    // A configuration value
    public ConfigOption<string, Config> AnyValue { get; private set; } = null!;

    private void InitProperties()
    {
        AnyValue = ParentConfig == null 
            // The master option has a default value
            ? new(this, nameof(AnyValue), canBeOverridden: true, "default")
            // No default value for a sub-option
            : new(this, nameof(AnyValue));
    }
}

Config config = new(),
    user = config.SubConfig,
    admin = user.SubConfig;

CAUTION: There's no endless-recursion protection for the ParentConfig or the SubConfig properties!

Now users are able to override default values, and administrators are able to override default and/or user values:

// Still the default value
Assert.AreEqual("default", config.AnyValue.FinalValue);

// User overrides the default value
user.AnyValue.Value = "user";
Assert.AreEqual("default", config.AnyValue.Value);
Assert.AreEqual("user", config.AnyValue.FinalValue);

// Administrator overrides the user value
admin.AnyValue.Value = "admin";
Assert.AreEqual("admin", config.AnyValue.FinalValue);

// User can't override the administrator value (but still store his own value 
// in case the administrator would unset his value)
user.AnyValue.Value = "test";
Assert.AreEqual("admin", config.AnyValue.FinalValue);
Assert.AreEqual("test", user.AnyValue.Value);

NOTE: Setting an option value is thread-safe.

It's also possible to flip the hierarchy:

Using this hierarchy an administrator could also allow or deny overriding values at any time, for example.

The hierarchy depth isn't limited.