JamSoft.Helpers 1.2.1

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JamSoft.Helpers

A collection of general helpers for applications and libraries. The goal is to provide convienience methods and core building blocks. All in a unit tested, cross-platform .NET Standard 2.0 library with minimal dependencies.

Table of Contents

• Docs
• Installation
• Tests
• Configuration
• Dirty Object Tracking
• Collections
• Environment Variables
• Cryptography
• Graphics
• Human Readable UI Values
• Math
• Strings
• Serialization
• Mvvm Pattern
• Observer Pattern
• Memento Pattern

Docs

https://jamsoft.github.io/JamSoft.Helpers/

Installation

Nuget

Install-Package JamSoft.Helpers -Version 1.2.1

CLI

dotnet add package JamSoft.Helpers --version 1.2.1

Package Reference

<PackageReference Include="JamSoft.Helpers" Version="1.2.1" />

Package Reference

paket add JamSoft.Helpers --version 1.2.1

Tests

There is a high level of test coverage as shown in the badge above (around 97%), however, at the moment the pipeline executes only on Windows which means some tests cannot be run in this environment. The library has been fully tested on Windows 10, OSX Catalina and Fedora 31.

The following test classes also show basic example implementations and uses of the provided pattern classes.

• ObserverTests
• MementoTests
• MyTestViewModel
• ATestSettingsClass
• BTestSettingsClass
• PersonViewModel

Configuration

Rather than getting embroiled in the convoluted and sometimes awkward user settings infrastructure provided by .NET (*.settings), sometimes you just want to store some values in a file, yes?

The issues and additional complications around user.config and strong names can sometimes get in the way. Using the SettingsBase<T> class can bypass this.

Set Up

Create a POCO class containing your settings properties, default values and inherit SettingsBase<T>, such as:

public sealed class MySettings : SettingsBase<MySettings>
{
    public string ASetting { get; set; } = "A Default Value";
}

Loading & Access

Now you can load, save and manage your settings at rumetime like:

string myDefaultSettingsPath = "C:\Some\location\on\disk";
MySettings.Load(myDefaultSettingsPath);

This call will either load the settings from a file called mysettings.json, the name is automatically taken from the type name, or if no file exists, the defaults are loaded.

You can also load and save from a provided file name instead of deriving from the type name, such as:

string myDefaultSettingsPath = "C:\Some\location\on\disk";
MySettings.Load(myDefaultSettingsPath, "custom-name.json");

You can access the values using the instance:

var theValue = MySettings.Instance.ASetting;

Or

MySettings.Instance.ASetting = theValue;

Saving

Saving the settings is a call to the Save() method, like:

MySettings.Save();

This will always save back to the same file the settings were originally loaded from, or if there was no file, the file will be created and the settings saved.

Reset

You can easily return back to the defaults by calling the ResetToDefaults() method, like:

MySettings.ResetToDefaults();

This will reset all settings to their default values and immediately write them to disk. If you do not want to write them to disk, simply pass a false to the method.

MySettings.ResetToDefaults(saveToDisk:false);

Dirty Object Tracking

Using the attributes and validators you can track classes with changes, such as view models, in order save new data or update UI state accordingly.

The Interface

There are a number of ways of implementing something like such as decorators and so forth, but to keep this as pluggable as possible this feature makes use of an interface to implement on your validatable classes.

public interface IDirtyMonitoring
{
    /// <summary>
    /// A flag denoting if the object is dirty
    /// </summary>
    bool IsDirty { get; set; }
    
    /// <summary>
    /// The object hash value
    /// </summary>
    string Hash { get; set; }
}

First implement the interface on your own classes, such as:

public class PersonViewModel : IDirtyMonitoring
{
    public string Name { get; set; }
    [IsDirtyMonitoring]
    public string DisplayName { get; set; }
    public bool IsDirty { get; set; }    
    public string Hash { get; set; }
}

In this example only the DisplayName property is monitored for changes. After an object has completed being initialised and is in it's "clean" state, validate it.

IsDirtyValidator.Validate(p);

Now, at any point in time you can validate it again to detect if the class is dirty.

p.DisplayName = "Original";
IsDirtyValidator.Validate(p).IsDirty; // false
p.DisplayName = "SomedifferentValue";
IsDirtyValidator.Validate(p).IsDirty; // true
p.DisplayName = "Original";
IsDirtyValidator.Validate(p).IsDirty; // false

Property & Field Tracking

As of v1.2.0 it is also possible to track which properties in a given object instance have changed. In order to track properties, call the Validate method and pass True as the trackProperties parameter.

IsDirtyValidator.Validate(p, trackProperties:true);

Now that the object, its properties and fields have been validated changes can be reported in more detail. Calls to the ValidatePropertiesAndFields() method will return collections of PropertyInfo and FieldInfo objects, such as:

var (props, fields) = IsDirtyValidator.ValidatePropertiesAndFields(p);

In the example above the props and fields collections contain details of the properties and fields that have changed since the previous validation process.

To restart this validation process on the same instance, simply re-validate it and pass True again.

IsDirtyValidator.Validate(p, true);

Dirty Monitoring Example Usage

public void LoadPeopleFromDataSource()
{
    var vms = Mapper.Map(_dataService.GetPeople());
    foreach(var vm in vms)
    {
        IsDirtyValidator.Validate(p, trackProperties:true);
        ...
    }
}

public void SaveUiState()
{
    foreach(var vm in _people)
    {
        if(IsDirtyValidator.Validate(vm).IsDirty)
        {
            // save logic
            
            var (props, fields) = IsDirtyValidator.ValidatePropertiesAndFields(vm);
            // more granular save logic
        }
    }
}

Collections

Shuffle Collections

IEnumerable<int> ints = new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
IEnumerable<int> shuffledInts = ints.Shuffle();

Or you can provide your own instance of Random.

Random randomiser = new Random();
IEnumerable<int> ints = new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
IEnumerable<int> shuffledInts = ints.Shuffle(randomiser);

Environment

There are a handful of helper methods and classes for access environment variables on various platforms.

Common Variables

var path = EnvEx.GetVariable(EnvExVariableNames.Path);

Windows Variables

var appData = EnvEx.GetVariable(EnvExWinVariableNames.AppData); // C:\Users\username\AppData\Roaming

OSX Variables

var shell = EnvEx.GetVariable(EnvExOsxVariableNames.Shell); // "/bin/bash"

Linux Variables

var manPath = EnvEx.GetVariable(EnvExLinuxVariableNames.ManPath); // ":"

More variables names are included in the library than are shown above. You can make use of these via helper constants in the following classes:

• EnvExVariableNames (Common)
• EnvExWinVariableNames
• EnvExOsxVariableNames
• EnvExLinuxVariableNames

Since the EnvEx.GetVariable method just takes a string, any value can be passed, such as:

var envValue = EnvEx.GetVariable("MYVARIABLENAME");

On Window you can also pass a target parameter of type EnvironmentVariableTarget. The default for this is Process as Linux and OSX do not support this parameter. If anything other than Process is passed on a non-Windows platform it will be defaulted to Process to prevent exceptions being raised.

Cryptography

There is a new little class to help digitally sign data with RSA Cryptography. The main class is created via a factory which can be registered in your DI container of choice.

public interface IRsaCryptoFactory
{
}

container.Register<IRsaCryptoFactory, RsaCryptoFactory>();

You can then use this factory to obtain instances of the service.

var crypto = cryptoFactory.Create();

There are many overloads of the create method to control how the service is built and how you want it configued.

You should also wrap each use of this within a using statement such as:

using(var crypto = cryptoFactory.Create(_privateKey, _publicKey, HashAlgorithmName.SHA512, RSASignaturePadding.Pkcs1))
{
   // do your stuff.
}

Once you have created an instance if you do not provide either of the keys, you can obtain the used keys for storage via the two properties, such as:

var crypto = cryptoFactory.Create();
var publicKey = sut.PublicKey;
var privateKey = sut.PrivateKey;

Graphics

Convert to HEX

int red = 121;
int green = 155;
int blue = 56;

var hex = Graphics.Colors.ToHex(red, green, blue);

Or you can also use an alpha value.

var hex = Graphics.Colors.ToHex(alpha, red, green, blue);

You can also pass values as an array

var hex = Graphics.Colors.ToHex(new[] { alpha, red, green, blue });

Convert to RGB

int red = 255;
int green = 169;
int blue = 104;

var color = Graphics.Colors.ToRgb("#FFA968");

Convert to ARGB

This can be useful for WPF and XAML which supports an alpha value in the HEX.

int alpha = 255;
int red = 146;
int green = 145;
int blue = 145;

var c = Graphics.Colors.ToArgb("#FF929191");

UI Values

Data Sizes

Converts integer and long values representing data sizes to human readable form

int input = 10000000;
input.ToHumanReadable(); returns "9.54 Mb"

long input = 2000000000000000000;
input.ToHumanReadable(); returns "1.73 Eb"

Time

double input = 3657;
input.ToTimeDisplayFromSeconds() returns "01:00:57"

double input = 3657.12;
input.ToTimeDisplayFromSeconds(withMs: true) returns "01:00:57:120"

Math

Even or Odd

Even number detection

int value = 2;
var isMyNumberEven = value.IsEvenNumber();

Percentages

Basic percentage calculations

int value = 500;
int total = 2000;

var percent = value.IsWhatPercentageOf(total) // 25

Strings

Hamming Distance

Calculates the number of edits required to go from one string to another must be equal lengths to start

var inputOne = "InputString1";
var inputTwo = "InputString2";

var distance = Distance.GetHammingDistance(inputOne, inputTwo);
inputOne.HammingDistanceTo(inputTwo)

Levenshtein Distance

Calculates the number of edits required to go from one string to another

var inputOne = "InputString1";
var inputTwo = "InputString2";

var distance = Distance.GetLevenshteinDistance(inputOne, inputTwo);
inputOne.LevenshteinDistanceTo(inputTwo)

Shorten Strings

This method allows you to shorten strings to a predetermined length and pad with ... or any pattern you provide.

string input = "Thisismylongstringthatneedsshortening";
var result = input.DotShortenString(10, 20); // "Thisism...shortening"

string input = "Thisismylongstringthatneedsshortening";
var result = input.DotShortenString(10, 20, ";;;"); // "Thisism;;;shortening"

Remove All Multispaces

var input = "  This  has    too  many  spaces   ";
input.RemoveAllMultiSpace(); // " This has too many spaces "

var input = "  This  has    too  many  spaces   ";
input.RemoveAllMultiSpace(trim:true); // "This has too many spaces"

var input = "  This  has    too  many  spaces   ";
input.RemoveAllMultiSpace("--"); // "--This--has--too--many--spaces--"

var input = "  This  has    too  many  spaces   ";
input.RemoveAllMultiSpace(pattern:"--", trim:true) // "This--has--too--many--spaces"

String Compare

string input = "string1";
string pattern = "strinG1";

input.IsExactlySameAs(pattern); // false

Serialization

XML Encoding Formatting

Adds a strict uppercased UTF-8 to XML declarations

using (var sw = new UppercaseUtf8StringWriter())
{
    xsSubmit.Serialize(sw, new TestObject { SomeProperty = "SomeValue" });
    xml = sw.ToString();
}

Patterns

Mvvm

A very bare bones view model with property changed updates

public abstract class ViewModelBase : INotifyPropertyChanged
{
    ...
    public bool IsEditable ...
    ...
    public bool IsBusy ...
    ...
    protected virtual bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = "")
    {
        ...
    }
}

Mvvm - SuperObservableCollection<T>

An observable collection that mutes change notifications when adding a range of objects and allows sorting

public class SuperObservableCollection<T> : ObservableCollection<T>
{
    public SuperObservableCollection(IEnumerable<T> coll)
    {
    }

    public void AddRange(IEnumerable<T> list, bool suppressNotifications = true, bool notifiyOnceAllAdded = true)
    {
        ...
    }

    public void Sort(bool suppressNotifications = false)
    {
        ...
    }
	
    public void Sort(IComparer<T> comparer, bool suppressNotifications = false)
    {
        ...
    }
}

Observer

A very basic implementation of the core bits of the observer pattern

public interface IObservable
{
    void Attach(IObserver observer);

    void Detach(IObserver observer);

    void Notify();
}

public interface IObserver
{
    void Update(IObservable observable);
}

public abstract class ObservableBase : IObservable
{
}

Memento

public interface IMemento
{
    object GetState();
}

public interface IMementoOwner
{
    IMemento Save();

    void Restore(IMemento memento);
}

public class MementoManager
{
    ...
}