README.md

        Schema

namespace Friflo.Json.Fliox.Schema

This namespace contains classes and methods to transform / generate Type Schemas.
For example to generate a JSON Schema from given C# model classes or vice vera.
The schema transformation can be used for any types like database schemas or JSON based protocols.

Another objective of this namespace is to enables type validation for JSON payloads.

Currently supported input type schemas are:

• C#
• JSON Schema

From these input schemas the following output schemas can be generate:

• C#
• Typescript
• Kotlin
• HTML
• JSON Schema / OpenAPI
• GraphQL
• Mermaid

The links in the table above navigate to pages utilizing the generated schemas. See screenshots below.

🎨 Features

• Code generators and JSON Validator support the C#/.NET language features:

  • general language types like class, struct and enum
  • primitives types like long, int, short, byte, bool, float & double
    Note: intentionally no support of non CLS-compliant primitive types: ulong, uint, ushort & sbyte
  • value types of BCL - .NET Base Class Library: Guid, DateTime and BigInteger
  • Nullable<> structs, primitives and enums
  • container types like: arrays, List<>, Dictionary<,>, Queue<>, Stack<>, ...
  • polymorphic classes with discriminator and discriminants.
  • namespaces
  • C# documentation comments

• Create clear and concise messages for validation errors. E.g.
  Missing required fields: [id, name] at Article > (root), pos: 2

• The JSON Validator is trimmed towards performance by minimizing GC/ Heap pressure and aiming for high memory locality.
  In case of small JSON payloads validation reaches 1.000.000 validations / second.

• Code generators are designed to be small and easy to maintain ~ 300 LOC / language.
  Also their performance reaches 10.000 schema transformations / second for smaller schemas.

• The generated JSON Schema files are compatible to the specification JSON Schema Draft-07.
  This enables using external JSON Schema validators to validate JSON files against the generated schemas.
  E.g. by Ajv JSON schema validator running in Node.js or in a browser.

• The generated schemas for various languages are directly available via a Fliox Hub in the Browser.
  To retrieve a zip or a single file click on a schema or type link in the Hub Explorer and follow the link Typescript, C#, Kotlin, JSON Schema / OpenAPI on the top of the schema page.

📷 Screenshots

Try out the web pages shown as screenshots below.
They are linked by the online DemoHub Explorer (EC2 instance: t2-micro, us-east-1)

Link symbol	links to
	Schema documentation
	Class Diagram
	OpenAPI Specification - Swagger UI
	GraphQL API - GraphiQL

Class Diagram

screenshot: MonitorStore schema as class diagram

Schema Documentation

screenshot: MonitorStore schema as single page HTML

Swagger UI

screenshot: monitor database with Swagger UI

GraphiQL

screenshot: monitor database with GraphiQL

Examples

JSON Schema Validation

The input for JsonValidator.Validate() is the JSON string and the Type defining the schema - Person in the example below.
Requires nuget package Friflo.Json.Fliox .

More examples are at Fliox.Examples.

    class Person
    {
                    public  int     age;
        [Required]  public  string  name;
    }
    
    public static class SchemaValidation
    {
        /// Validate JSON with a Schema
        [Test]
        public static void Run() {
            var json = "{\"age\":42,\"name\":\"Peter\"}";
            var success = JsonValidator.Validate(json, typeof(Person), out var error);
            Assert.IsTrue(success);

            json = "{\"age\":42}";
            success = JsonValidator.Validate(json, typeof(Person), out error);
            Assert.IsFalse(success);
            Assert.AreEqual("Missing required fields: [name] at Person > (root), pos: 10", error);
        }
    }

Code generation

The input for code generation is the type defining the schema - Person in the example below.

    /// Generate types for: C#, GraphQL, HTML, JSON Schema, Kotlin, Markdown and Typescript in folder: ./schema
    public static void GenerateSchemaModels() {
        var schemaModels = SchemaModel.GenerateSchemaModels(typeof(Person));
        foreach (var schemaModel in schemaModels) {
            var folder = $"./schema/{schemaModel.type}";
            schemaModel.WriteFiles(folder);
        }
    }

More examples

• A code example showing code generation based on a C# Type is shown at FlioxClient

• Examples for code generation and JSON type validation at:
  Schema generators & JSON Validation tests

• Schema validation for an EntityDatabase by a JSON.Fliox server is demonstrated at:
  TestServer