Event Schema

The Hermodr.Schema package adds the ability to formally describe the structure of your events — what properties they carry, their types, and constraints — and to validate CloudEvent instances against those descriptions before publishing.

Installation

dotnet add package Hermodr.Schema

What's included

Type	Role
IEventSchema / EventSchema	The schema model
EventSchemaBuilder	Fluent API for building a schema in code
EventSchemaCreator	Derives a schema from an annotated class using reflection
IEventSchemaFactory	DI-friendly factory wrapping EventSchemaCreator
IEventSchemaWriter	Abstraction for schema serialisation (JSON, YAML, AsyncAPI)
EventSchemaJsonWriter	Serialises a schema to JSON
IEventSchemaValidator	Validates a CloudEvent against a schema

Pages in this section

Page	Description
Fluent Builder	Build a schema programmatically
From Annotations	Derive a schema from [Event]-annotated classes
Export as JSON	Serialise a schema to a JSON document
Export as YAML	Serialise a schema to a YAML document
Export as AsyncAPI	Generate complete AsyncAPI 2.x documents
Validation	Validate CloudEvent instances against a schema

Schema model at a glance

An IEventSchema carries:

• Type — the event type string (e.g. "order.placed")
• Version — the SemVer version of the schema
• ContentType — MIME type of the event data
• Description — human-readable description
• Properties — a collection of IEventProperty entries, each with:
  • Name, DataType, Description
  • Constraints: Required, Nullable, Range<T>, Enum