Nucs.JsonSettings.Autosave

JsonSettings

This library aims to simplify the process of creating configuration for your C# app/service by utilizing the serialization capabilities of Json.NET to serialize nested (custom) objects, dictionaries and lists as simply as by creating a POCO and inheriting JsonSettings class.

📖 Full documentation & API reference: nucs.github.io/JsonSettings

Installation

dotnet add package Nucs.JsonSettings
dotnet add package Nucs.JsonSettings.Autosave        # optional, for [AutoSave] and EnableAutosave()
dotnet add package Nucs.JsonSettings.NotifyChanges   # optional, for [NotifyChanges] data binding

All packages are signed and supported runtimes are: netstandard2.0, net48, net6.0, net8.0 and net10.0.

Table of Contents

• 📖 Documentation Website
• Features Overview
• The Basics
• Modules
  • Recovery
  • Versioning
  • Encryption
  • Autosave
    • Suspend Saving
    • WPF Support with INotifyPropertyChanged/INotifyCollectionChanged
    • Throttled Save
• Dynamic Settings Bag
• Changing JsonSerializerSettings
• Converters
• Modulation Api
• Native AOT and Trimming
• License

Features Overview

• Initialized in a fluent static API read more
• Cross-platform, multi-targeting netstandard2.0, net48, net6.0, net8.0 and net10.0
• Modularity allowing easy extension and high control over behavior on a per-object level read more
• Autosaving on changes read more
  • Via INotifyPropertyChanged/INotifyCollectionChanged allowing WPF binding read more
  • Via compile-time IL weaving of the property setters, marked with [Autosave] read more
• Versioning control read more
  • Offers protection mechanisms such as renaming file and loading default
  • By changing version, it allows to introduce any kind of changes to the settings class
• Customizable control over recovering from parsing exceptions read more
• AES256 Encryption via a key read more
• Fully extensible with Json.NET 's capabilities, attributes and settings
  • It'll be accurate to say that this library is built around Json.NET
• SettingsBag, a dynamic option that uses a ConcurrentDictionary<string,object> eliminating the need for hardcoding POCO class read more

The Basics

Test project: https://github.com/Nucs/JsonSettings/tree/master/tests/JsonSettings.Tests

Serialization Guide: https://www.newtonsoft.com/json/help/html/SerializationGuide.htm

JsonSettings is the base abstract class serving as the base class for all settings objects the user defines.

Creation, loading is done through static API where saving is through the settings object API.

Here is a self explanatory quicky of to how and what:

• Hardcoded settings

//Step 1: create a class and inherit JsonSettings
class MySettings : JsonSettings {
    //Step 2: override a default FileName or keep it empty. Just make sure to specify it when calling Load!
    //This is used for default saving and loading so you won't have to specify the filename/path every time.
    //Putting just a filename without folder will put it inside the executing file's directory.
    public override string FileName { get; set; } = "TheDefaultFilename.extension"; //for loading and saving.

    #region Settings

    public string SomeProperty { get; set; }
    public Dictionary<string, object> Dictionary { get; set; } = new Dictionary<string, object>();
    public int SomeNumberWithDefaultValue { get; set; } = 1;
    [JsonIgnore] public char ImIgnoredAndIWontBeSavedOrLoaded { get; set; }
    
    #endregion
    
    //Step 3: Override parent's constructors
    public MySettings() { }
    public MySettings(string fileName) : base(fileName) { }
}

//Step 4: Load
public MySettings Settings = JsonSettings.Load<MySettings>("config.json"); //relative path to executing file.
//or create a new empty
public MySettings Settings = JsonSettings.Construct<MySettings>("config.json");

//Step 5: Introduce changes and save.
Settings.SomeProperty = "ok";
Settings.Save();

• Dynamic settings
  • Dynamic settings will automatically create new keys.
  • Can accept any Type that Json.NET can serialize
  • ValueTypes are returned as Nullable<Type>, therefore if a key doesn't exist - a null is returned.

//Step 1: Just load it, it'll be created if doesn't exist.
public SettingsBag Settings = JsonSettings.Load<SettingsBag>("config.json");
//Step 2: use!
Settings["key"]  = "dat value tho";
Settings["key2"] = 123;
dynamic dyn = Settings.AsDynamic();
if ((int?)dyn.key2==123)
    Console.WriteLine("explode");
Settings.Save();

• Encrypted settings
  • Uses AES via System.Security.Cryptography (the .NET BCL); optional AES-GCM, AES-CCM, ChaCha20-Poly1305 or authenticated AES-CBC-HMAC.
  • Can be applied to any settings class because it is a module.
  • The secret can be a text password, a binary password, or a raw key.

MySettings Settings = JsonSettings.Load<MySettings>("config.json", q=>q.WithEncryption("mysecretpassword"));
SettingsBag Settings = JsonSettings.Load<SettingsBag>("config.json", q=>q.WithEncryption("mysecretpassword"));
//or
MySettings Settings = JsonSettings.Configure<MySettings>("config.json")
                     .WithEncryption("mysecretpassword")
               //or: .WithModule<EncryptionModule>("pass");
                     .LoadNow();

SettingsBag Settings = JsonSettings.Configure<SettingsBag>("config.json")
                     .WithEncryption("mysecretpassword")
               //or: .WithModule<EncryptionModule>("pass");
                     .LoadNow();

The secret can also be supplied as bytes. A byte[] password is stretched into the key with the same PBKDF2 derivation as a text password (salted and iterated); a raw key is used verbatim and must be 16, 24 or 32 bytes (AES-128/192/256):

// binary password - PBKDF2-derived, like a text password but with arbitrary bytes.
// Note: NOT the same credential as the text password whose UTF-8 bytes equal these.
byte[] password = Encoding.UTF8.GetBytes("mysecretpassword");
var a = JsonSettings.Configure<MySettings>("config.json").WithEncryption(password).LoadNow();

// raw AES key - used as-is, no derivation. You own the key's quality.
byte[] key = RandomNumberGenerator.GetBytes(32); // or from an env var / HSM / another KDF
var b = JsonSettings.Configure<MySettings>("config.json").WithEncryptionRawKey(key).LoadNow();

// both accept a fetcher, incl. one that receives the instance:
var c = JsonSettings.Configure<MySettings>("config.json")
                    .WithEncryptionRawKey(() => LoadKeyFromVault())
                    .LoadNow();

• Hardcoded Settings with Autosave
  • Automatic save will occur when any property changes
  • Works on any property — virtual is not required (as of 2.2.0); opt a property out with [IgnoreAutosave]
  • Requires package nucs.JsonSettings.Autosave and an [Autosave] attribute on the class.

Settings x  = JsonSettings.Load<Settings>().EnableAutosave(); //call after loading
//or:
ISettings x = JsonSettings.Load<Settings>().EnableIAutosave<Settings, ISettings>(); //Settings implements interface ISettings

x.Property = "value"; //Saved!

• Dynamic Settings with Autosave
  • Automatic save will occur when changes detected
  • note: SettingsBag has it's own implementation of EnableAutosave().

//Step 1:
SettingsBag Settings = JsonSettings.Load<SettingsBag>("config.json").EnableAutosave(); //call after loading
//Step 2:
Settings.AsDynamic().key = "wow"; //Saved!
Settings["key"] = "wow two"; //Saved!

Recovery

RecoveryModule provides handling for JsonException when calling JsonSettings.LoadJson during the loading process. On a scenario of exception/failure, one of the following actions can take place:

• RecoveryAction.Throw

  Will throw JsonSettingsRecoveryException with the real exception as inner exception.

• RecoveryAction.LoadDefault

  Default settings will be loaded without touching the existing file until next save.

• RecoveryAction.LoadDefaultAndSave

  Default settings will be loaded and saved to disk immediately.

• RecoveryAction.RenameAndLoadDefault

  Will append the version to the end of the faulty file's name and load the default settings and save to disk.

  i.e. myfile.json versioned 1.0.0.5 will be renamed to myfile.1.0.0.5-0.json if it fails on parsing (the trailing -0 is a collision counter — a second archive becomes -1, and so on) and the new default settings will be saved as the original filename.

All recovery properties and methods are suited for inheritance so extending is quite easy.

using Nucs.JsonSettings.Fluent;
using Nucs.JsonSettings.Modulation.Recovery;

//attach RecoveryModule via the fluent extension and pick what happens on a parse failure:
var settings = JsonSettings.Configure<MySettings>("config.json")
                           .WithRecovery(RecoveryAction.RenameAndLoadDefault)
                           .LoadNow();

settings.SomeProperty = "hello";
settings.Save();

//...later config.json is corrupted on disk (hand-edited, truncated, a half-finished write).
//Loading again does NOT throw: the corrupt file is renamed aside and defaults are loaded.
settings = JsonSettings.Configure<MySettings>("config.json")
                       .WithRecovery(RecoveryAction.RenameAndLoadDefault)
                       .LoadNow();
//config.json is now the freshly-saved default; the corrupt copy is preserved next to it as
//config.<version>-0.json (or config.0.json when the class is not IVersionable).

Recovery composes with versioning: versioning runs when the file parses, recovery catches the parse itself failing.

Versioning

VersioningModule<T> provides the ability to enforce a specific version so when new changes are introduced to your Settings class (scheme), a user-defined action can take place. Any of the following actions can be taken:

• VersioningResultAction.DoNothing

  Will keep the old version if it was parsed by Json.NET successfully. otherwise RecoveryModule will handle the failure of loading.

• VersioningResultAction.Throw

  Will throw JsonSettingsRecoveryException with the real exception as inner exception.

• VersioningResultAction.LoadDefault

  Default settings will be loaded without touching the existing file until next save.

• VersioningResultAction.LoadDefaultAndSave

  Default settings will be loaded and saved to disk immediately.

• VersioningResultAction.RenameAndLoadDefault

  Will append the version to the end of the faulty file's name and load the default settings and save to disk.

  i.e. myfile.json versioned 1.0.0.5 will be renamed to myfile.1.0.0.5-0.json if it fails on parsing (the trailing -0 is a collision counter — a second archive becomes -1, and so on) and the new default settings will be saved as the original filename.

There are two ways to specify which version to enforce.

1. Pass the version when calling WithVersioning.

2. Add [EnforcedVersion("1.0.0.0")] attribute to your IVersionable.Version property definition.

   When dealing with inheritance/virtual override, the attribute of the lowest inherited class will be used.

using Nucs.JsonSettings.Fluent;
using Nucs.JsonSettings.Modulation;

//The settings class must implement IVersionable (contributes `Version Version { get; set; }`).
class MySettings : JsonSettings, IVersionable {
    public override string FileName { get; set; } = "config.json";
    public virtual Version Version { get; set; } = new Version(1, 0, 0, 0);
    public string Theme { get; set; } = "dark";

    public MySettings() { }
    public MySettings(string fileName) : base(fileName) { }
}

//1) Pass the enforced version explicitly:
var settings = JsonSettings.Configure<MySettings>("config.json")
                           .WithVersioning("1.0.0.0", VersioningResultAction.RenameAndLoadDefault)
                           .LoadNow();

//Later you ship a new scheme and bump the enforced version. A file still written as 1.0.0.0 no
//longer matches, so it is renamed to config.1.0.0.0-0.json and a fresh default config.json is saved.
settings = JsonSettings.Configure<MySettings>("config.json")
                       .WithVersioning("2.0.0.0", VersioningResultAction.RenameAndLoadDefault)
                       .LoadNow();

//2) ...or bake the version into the class with [EnforcedVersion] and use the version-less overload:
//     [EnforcedVersion("2.0.0.0")]
//     public virtual Version Version { get; set; } = new Version(1, 0, 0, 0);
var byAttribute = JsonSettings.Configure<MySettings>("config.json")
                              .WithVersioning(VersioningResultAction.RenameAndLoadDefault)
                              .LoadNow();

Policy

A comparison between versions is done by the Policy which is a VersioningPolicyHandler delegate ((Version, Version) => bool) passed during the construction of VersioningModule<T> or falls back to static VersioningModule<T>.DefaultPolicy which can be changed.

It is possible to change the static default policy by changing VersioningModule<T>.DefaultPolicy although each VersioningModule<T> can be assigned its own policy.

By default the versions must match exactly:

static bool DefaultEqualPolicy(Version version, Version expectedVersion) {
    return expectedVersion?.Equals(version) != false;
}

Encryption

The default is AES-256-CBC over the serialized JSON (UTF-8 bytes), using only System.Security.Cryptography (the .NET base class library) — no third-party cryptography. The file holds a random IV followed by the AES-CBC ciphertext. Add WithBase64() to additionally store the result as copy-pasteable base64 text.

The secret comes in three forms:

Call	Secret	How it becomes the key
WithEncryption(string) / WithEncryption(SecureString)	text password	PBKDF2 (salted, iterated)
WithEncryption(byte[])	binary password	the same PBKDF2 derivation, over the raw bytes
WithEncryptionRawKey(byte[])	raw AES key (16/24/32 bytes)	used verbatim, no derivation

Each also has Func<...> and Func<T, ...> overloads for resolving the secret lazily (e.g. from a vault or an environment variable).

Notes:

• A byte[] password is a different credential from the text password whose UTF-8 encoding equals those bytes — the text derivation folds in the string's character length, which raw bytes do not carry. Pick one form per file.
• A raw key skips PBKDF2, so its strength is entirely the key you provide; supply high-entropy key material (e.g. RandomNumberGenerator.GetBytes(32)), not a low-entropy value.
• The on-disk format is identical across all three (a random IV followed by AES-CBC blocks), and the text-password path is byte-for-byte compatible with every earlier version.

// text password (classic)
JsonSettings.Configure<MySettings>("config.json").WithEncryption("mysecretpassword").LoadNow();

// binary password (PBKDF2-derived)
JsonSettings.Configure<MySettings>("config.json").WithEncryption(passwordBytes).LoadNow();

// raw key (verbatim, 16/24/32 bytes for AES)
JsonSettings.Configure<MySettings>("config.json").WithEncryptionRawKey(key32).LoadNow();

The default AesCbc is unauthenticated and on-disk compatible with every earlier version. Pass an EncryptionAlgorithm to choose another — including authenticated algorithms that detect a tampered file, not only keep it confidential:

// authenticated AEAD (.NET 6.0+)
JsonSettings.Configure<MySettings>("config.json").WithEncryption("password", EncryptionAlgorithm.AesGcm).LoadNow();
JsonSettings.Configure<MySettings>("config.json").WithEncryptionRawKey(key32, EncryptionAlgorithm.ChaCha20Poly1305).LoadNow();

AesCbc and AesCbcHmac are available on every target framework; AesGcm, AesCcm and ChaCha20Poly1305 require .NET 6.0+. There is no algorithm marker in the file, so read it back with the same algorithm it was written with; only AesCbc reads files from older versions. Encryption runs entirely on System.Security.Cryptography — there is no third-party cryptographic dependency.

Autosave

Autosaving appends a save to the end of every property setter of a class marked [Autosave]. This happens at compile time, via IL weaving (AspectInjector), in the assembly that declares the class. Nothing is generated at runtime.

[Autosave]
public class MySettings : JsonSettings {
    public override string FileName { get; set; } = "config.json";
    public string Name { get; set; }        // no 'virtual' required
    public int    Count { get; set; }
}

var settings = JsonSettings.Load<MySettings>("config.json").EnableAutosave();
settings.Name = "changed";   // saved

What changed in 2.2.0

Autosave used to build a runtime proxy with Castle.Core, which forced three restrictions that are now gone:

Before (Castle.DynamicProxy)	Now (compile-time weaving)
Every public property had to be virtual	Ordinary properties work; virtual is irrelevant
The class could not be sealed	sealed classes work
EnableAutosave() returned a different object, so a reference captured beforehand silently did not autosave	Returns the same instance; every reference to it autosaves
Impossible under Native AOT (System.Reflection.Emit)	No runtime codegen at all

In exchange there is one new requirement: the class must carry [Autosave]. Calling EnableAutosave() on a class without it throws JsonSettingsException rather than silently doing nothing.

[Autosave] is not inherited. A setter is woven where it is declared, so every class in a settings hierarchy that declares properties you want saved needs its own attribute.

Two smaller behavioural notes for anyone migrating from 2.1.0:

• virtual is no longer an opt-out. Under the proxy, a non-virtual property was silently skipped; some code relied on that to keep a property out of autosaving. Every setter is now woven regardless of virtual, so a property that must not autosave has to say so with [IgnoreAutosave] (or [JsonIgnore]).
• EnableAutosave() is idempotent. Calling it twice on the same instance returns that instance and does not attach a second autosave module.

The Castle-era JsonSettingsAutosaveExtensions.Options field (a Castle.DynamicProxy.ProxyGenerationOptions) is removed, since the type it exposed no longer exists in the dependency graph.

Attributes

Properties can be marked with IgnoreAutosaveAttribute (JsonIgnoreAttribute will also work) to be excluded from the monitored properties for changes. This applies to collections too: an [IgnoreAutosave] ObservableCollection does not save when its contents change.

Behaviour notes

• Indexers are not monitored. Writing settings[key] = value does not autosave — an indexer is not a serializable property. Use a normal property or call Save().
• Reentrancy is safe. Writing a monitored property from inside an AfterSave handler does not trigger another save (it would otherwise recurse); the value is kept in memory and persists on the next save.
• SuspendAutosave nests. Nested suspension scopes are reference-counted and collapse into a single save when the outermost scope closes; an inner scope closing does not end suspension.
• A failing save surfaces at the assignment. If the triggered Save() throws, the exception propagates out of the property assignment (the new value is already set in memory).
• Disposing the settings unbinds autosave, including handlers attached to nested collections.
• Loading does not autosave. Load(), LoadDefault() and a versioning reload populate the object from disk through its setters; those writes are not user edits and do not save back (autosave resumes normally afterward).
• IVersionable.Version is not monitored. It is framework metadata managed by the versioning module and rides along in every ordinary save, so changing it does not by itself autosave. (A property named Version on a class that does not implement IVersionable is ordinary user data and is monitored.)

Requirements

• Install nucs.JsonSettings.Autosave nuget package
• Mark the settings class [Autosave]
• Call mySettings.EnableAutosave() extension after calling Load

How the weave runs (out of process, since 2.3.0)

AspectInjector's stock in-process MSBuild task leaks file handles into the MSBuild node, which deterministically failed small executable consumers at the SDK's CreateAppHost step (MSB4018 / "The process cannot access the file '<App>.dll' because it is being used by another process") — merely referencing the package was enough. Since 2.3.0 the shipped build targets run the identical weaver task in a short-lived child MSBuild process instead, so every leaked handle is closed at child exit before CreateAppHost runs; weaving behaviour and incrementality are unchanged. Opt back into the in-process weave with <NucsJsonSettingsOutOfProcWeave>false</NucsJsonSettingsOutOfProcWeave>. See docs/aspectinjector-2.9.0-apphost-lock.md for the full forensics.

Strong-named consumers

IL weaving rewrites the assembly after the compiler has signed it, and AspectInjector 2.9.0 retired its re-signing feature. The package therefore ships MSBuild targets that re-sign the assembly with your own $(AssemblyOriginatorKeyFile) after the weave. If sn.exe cannot be found the build warns (NJS1001) rather than failing; opt out entirely with <NucsAutosaveResignAfterWeaving>false</NucsAutosaveResignAfterWeaving>.

Suspend Autosave

In some scenarios, there might be multiple close changes to the configuration object. Normally that would trigger multiple save calls.

To prevent that, the developer can create a SuspendAutosave object which will postpone the save to when SuspendAutosave will be disposed or Resume called. If there were no changes between the allocation of SuspendAutosave object and disposal/resume then save won't be called.

var settings = JsonSettings.Load<MySettings>("config.json").EnableAutosave();

using (settings.SuspendAutosave()) {
    settings.Width  = 800;    // does not save yet
    settings.Height = 600;    // does not save yet
    settings.Title  = "App";  // does not save yet
}                             // one save here on dispose — and only if something changed

//or drive it manually instead of a using-block:
var suspender = settings.SuspendAutosave();
settings.Width = 1024;
suspender.Resume();  // commits the single pending save (same as Dispose); a second call is a no-op

SuspendAutosave() resolves the object's suspension module — the AutosaveModule on a woven class, the bag's own SettingsBagAutosaveModule on a SettingsBag — so call EnableAutosave() first. Scopes are reference-counted and nest — only the outermost one commits, once.

WPF Support with INotifyPropertyChanged/INotifyCollectionChanged

Any settings class can turn into a ViewModel with full autosave support making window settings and state persistence much simpler.

When your settings class inherits INotifyPropertyChanged, upon calling EnableAutosave, a NotificationBinder is attached to the settings object that'll listen to the settings class's:

• event PropertyChanged calls
• All properties that implement INotifyPropertyChanged will bind to their event PropertyChanged
• All properties that implement INotifyCollectionChanged such as ObservableCollection<T> will bind to their event CollectionChanged
• All other properties save through their woven setter (virtual is not required as of 2.2.0).

So evidently, objects inside ObservableCollection or other nested properties that are not in the settings class are not monitored for changes.

Saving on a plain property write is handled by the woven setter, so a hand-written setter that raises OnPropertyChanged and an auto-implemented one behave identically. The NotificationBinder is what re-binds nested INotifyPropertyChanged / INotifyCollectionChanged objects when the property holding them is replaced.

Requirements

• Settings class inherit INotifyPropertyChanged (e.g. by deriving NotifiyingJsonSettings)
• Mark the settings class [Autosave]
• Install nucs.JsonSettings.Autosave nuget package
• Call mySettings.EnableAutosave() extension after calling Load

Producing notifications for the View — [NotifyChanges]

The above makes autosave react to PropertyChanged. To make a setter raise it — so a binding (WPF, WinForms, Avalonia, WinUI, MAUI, Uno) refreshes — without hand-writing OnPropertyChanged() in every setter, including on auto-properties (which otherwise save but never notify), install the separate Nucs.JsonSettings.NotifyChanges package and mark the class [NotifyChanges]:

[Autosave, NotifyChanges]                     // [Autosave] from Nucs.JsonSettings.Autosave,
public class WindowSettings : NotifiyingJsonSettings {   // [NotifyChanges] from Nucs.JsonSettings.NotifyChanges
    public override string FileName { get; set; } = "window.json";
    public double Width { get; set; }   // binds two-way, saves, and notifies — no boilerplate
    public string Title { get; set; }
}

• Compile-time weave like [Autosave], not inherited, and composes with it (one write saves and notifies once). Put it on auto-properties — a hand-written setter that already calls OnPropertyChanged() would notify twice. Framework-neutral: depends only on System.ComponentModel, not on WPF.
• NotificationGuard controls when it fires, per class or per property: OnlyChanged (default), SkipNullOrDefault, Always — and they combine ([Flags]).
• Silence a property with [IgnoreNotify] (independent of [IgnoreAutosave] — a property can save without notifying, or the reverse); framework FileName/Modulation/Version never notify.
• The class must own the event: NotifiyingJsonSettings, or an MVVM base recognised by convention (OnPropertyChanged / RaisePropertyChanged / NotifyOfPropertyChange). For a class with no base, [NotifyChangesMixin] injects INotifyPropertyChanged for you (per-instance; best for a single class — a hierarchy should use NotifiyingJsonSettings + [NotifyChanges]).
• Also raises INotifyPropertyChanging before the change (on NotifiyingJsonSettings, a convention raiser, or the mixin), fans a change out to a computed property with [NotifyChangesFor(nameof(…))], and marshals notifications onto the UI thread for off-thread writes via EnableNotificationMarshaling().

See the Notifications & Data Binding guide for the guard details, the mixin, INotifyPropertyChanging, [NotifyChangesFor], SynchronizationContext marshalling, nested-collection autosave, threading, and a comparison with Fody PropertyChanged, CommunityToolkit.Mvvm and ReactiveUI.

For a runnable tour, examples/JsonSettings.Examples.UI is a WPF app in which every control is a bound settings property — the window's own position/size/title persist through the binding, and one tab per integration (guards, [NotifyChangesFor], the opt-outs, nested collections, the mixin, raiser conventions, EnableIAutosave, marshalling) shows its save/notification counters, an activity log and the JSON file on disk, live:

dotnet run --project examples/JsonSettings.Examples.UI -f net8.0-windows

Throttled Save

Upcoming feature...

Dynamic Settings Bag

SettingsBag internally stores a key-value dictionary. Any type of Value can be passed as long as Json.NET knows how to serialize it.

SettingsBag has built-in feature for autosaving that can be enabled by calling EnableAutosave without WPF binding support.

var bag = JsonSettings.Load<SettingsBag>("bag.json").EnableAutosave();
bag["Name"] = "value";           // saved
bag.Remove("Name");              // saved
dynamic d = bag.AsDynamic();
d.Other = 42;                    // saved (routes through the bag)

This is a separate autosave from the [Autosave] weaving used for typed classes — it is dictionary-backed, needs no attribute, and is what SettingsBag.EnableAutosave() (the instance method) turns on. Its own SettingsBagAutosaveModule shares the SuspensionModule state machine with the woven path, so it inherits the same guarantees: SuspendAutosave() (including nesting), reentrancy safety (writing the bag inside an AfterSave handler does not recurse), and Remove/RemoveWhere autosave like an index write.

Notes:

• Calling the EnableAutosave() extension on a JsonSettings-typed reference to a bag routes to the bag's own autosave, so it behaves the same as calling the instance method.
• AsDynamic() returns a disposable wrapper; using it after Dispose() throws ObjectDisposedException.

Changing JsonSerializerSettings

The default settings are defined on static JsonSettings.SerializationSettings.

public static JsonSerializerSettings SerializationSettings { get; set; } = new JsonSerializerSettings {
    Formatting = Formatting.Indented, 
    ReferenceLoopHandling = ReferenceLoopHandling.Ignore, 
    NullValueHandling = NullValueHandling.Include, 
    ContractResolver = new FileNameIgnoreResolver(), 
    TypeNameHandling = TypeNameHandling.Auto, 
    MaxDepth = 128
};

To alter the JsonSerializerSettings, it's best to understand how the library is resolving which settings to use during serialization/deserialization as follows:

/// <summary>
///     Returns configuration based on the following fallback: <br/>
///     settings ?? this.OverrideSerializerSettings ?? JsonSettings.SerializationSettings ?? JsonConvert.DefaultSettings?.Invoke()
///              ?? throw new JsonSerializationException("Unable to resolve JsonSerializerSettings to serialize this JsonSettings");
/// </summary>
/// <param name="settings">If passed a non-null, This is the settings intended to use, not any of the fallbacks.</param>
/// <exception cref="JsonSerializationException">When no configuration valid was found.</exception>
protected virtual JsonSerializerSettings ResolveConfiguration(JsonSerializerSettings? settings = null) {
    return settings
           ?? this.OverrideSerializerSettings
           ?? JsonSettings.SerializationSettings
           ?? JsonConvert.DefaultSettings?.Invoke()
           ?? throw new JsonSerializationException("Unable to resolve JsonSerializerSettings to serialize this JsonSettings");
}

1. settings parameter is an internal mechanism when handling defaults. If passed a non-null, This is the settings intended to use, not any of the following fallbacks.
2. this.OverrideSerializerSettings is a property in every class inheriting JsonSettings allowing personalized settings per object. The OverrideSerializerSettings property and ResolveConfiguration method are both virtual and can be overriden to redirect the resolving to where ever you see fit or with what-ever predefined value.
3. static JsonSettings.SerializationSettings is the default for all JsonSettings objects.
4. static JsonConvert.DefaultSettings is the default settings defined on a Json.NET level.

Converters

Defining converters or changing the serialization settings globally can be done by adding a converter to static JsonSettings.SerializationSettings as follows:

//call during app startup
JsonSettings.SerializationSettings.Converters.Add(new Newtonsoft.Json.Converters.VersionConverter());

Alternatively per object setting can be done by setting or inheriting JsonSettings.OverrideSerializerSettings property but it is important to also specify the default configuration so JsonSettings behavior will remain persistent (see more) .

JsonConverterAttribute

By far the easiest way to specify a converter is by specifying a JsonConverterAttribute on the property and Json.NET will do the rest.

[JsonConverter(typeof(ExchangeConverter))]
public ExchangeType Exchange { get; set; }

JsonConverterAttribute can also be specified on an interface property as it is used in IVersionable and will apply to any class inheriting it.

This is the best approach for other libraries because by specifying an attribute, no matter what JsonSerializerSettings will be specified by the developer, Json.NET will always serialize this property with the specified converter.

public interface IVersionable {
    [JsonConverter(typeof(Newtonsoft.Json.Converters.VersionConverter))]
    public Version Version { get; set; }
}

Modulation Api

Key points

• All modules are stored inside JsonSettings.ModuleSocket Modulation { get; }.
• ModuleSocket stores all modules attached to this JsonSettings object.
• Every settings object gets a new module object allocated for every module configured.
• Attaching modules is done via static extensions read more
• All modules provided by the library have properties and methods that are suited for inheritance so extending is easy.

using Nucs.JsonSettings.Fluent;
using Nucs.JsonSettings.Modulation;
using Nucs.JsonSettings.Modulation.Recovery;

//Attach a module fluently — by instance, or by type with constructor arguments:
var settings = JsonSettings.Configure<MySettings>("config.json")
                           .WithModule(new Base64Module())                                 // your own instance
                           .WithModule<MySettings, RecoveryModule>(RecoveryAction.LoadDefault) // constructed for you
                           .LoadNow();

WithEncryption, WithBase64, WithVersioning and WithRecovery are all thin wrappers over WithModule — e.g. WithRecovery(action) is exactly WithModule(new RecoveryModule(action)).

With Construct. Construct<T>(args) is the constructor-args sibling of Configure<T>(filename): both hand back a fresh, fully-configured instance that has not read the file yet, so you can wire up modules (or seed defaults in memory) before an explicit Load/Save:

//build a fresh instance, attach modules, then load explicitly:
var settings = JsonSettings.Construct<MySettings>("config.json") // ctor args go to your constructor
                           .WithModule(new Base64Module())
                           .WithEncryption("password")
                           .LoadNow();

//or use it purely in-memory — seed defaults and write them without reading an existing file:
var seeded = JsonSettings.Construct<MySettings>("config.json");
seeded.SomeProperty = "default";
seeded.Save();

Execution Order

The events are many to allow as much interception as possible.

The event handlers do not return any data but instead they receive a reference of the object that can be modified and will be used in the next stage.

Loading

event BeforeLoadHandler BeforeLoad(JsonSettings sender, ref string source); //source is the file that will be loaded.
event DecryptHandler Decrypt(JsonSettings sender, ref byte[] data);
event AfterDecryptHandler AfterDecrypt(JsonSettings sender, ref byte[] data);
event BeforeDeserializeHandler BeforeDeserialize(JsonSettings sender, ref string data);
event BeforeRepopulateHandler BeforeRepopulate(JsonSettings sender); //brackets the populate itself; fires on EVERY populate incl. LoadDefault and direct LoadJson
event AfterRepopulateHandler AfterRepopulate(JsonSettings sender, bool successfulPopulate); //from a finally; false when the populate threw halfway
event AfterDeserializeHandler AfterDeserialize(JsonSettings sender);
event AfterLoadHandler AfterLoad(JsonSettings sender, bool successfulLoad);

And in a case of JsonException during LoadJson

//recovered marks if a recovery from failure was successful, handled will prevent any further modules from attempting to recover.
//if recovered is returned false, JsonSettingsException will be thrown with the original exception as inner exception
event TryingRecoverHandler TryingRecover(JsonSettings sender, string fileName, JsonException? exception, ref bool recovered, ref bool handled);
event RecoveredHandler Recovered(JsonSettings sender);

Saving

event BeforeSaveHandler BeforeSave(JsonSettings sender, ref string destinition);
event BeforeSerializeHandler BeforeSerialize(JsonSettings sender);
event AfterSerializeHandler AfterSerialize(JsonSettings sender, ref string data);
event EncryptHandler Encrypt(JsonSettings sender, ref byte[] data);
event AfterEncryptHandler AfterEncrypt(JsonSettings sender, ref byte[] data);
event AfterSaveHandler AfterSave(JsonSettings sender, string destinition);

Cryptography / Encoding Decoding

When attaching to OnEncrypt event, it'll push to the end of the event queue - meaning it will receive the data after all the events/modules that were attached to it before.

When attaching to OnDecrypt, it is pushed to the beginning of the event queue.

Hence encryption/encoding and decryption/decoding is automatically in the right order.