oag-core

OpenAPI 3.x parser, intermediate representation, and transform pipeline.

This is the foundation crate — every other oag crate depends on it.

What it does

• Parses OpenAPI 3.x specs (YAML and JSON)
• Resolves all $ref pointers into concrete types
• Transforms specs into a typed intermediate representation (IrSpec)
• Normalizes names into PascalCase, camelCase, snake_case, and SCREAMING_SNAKE_CASE
• Detects Server-Sent Events streaming endpoints
• Groups operations into modules by tag

Transform pipeline

The spec-to-IR transform runs in five phases:

1. Resolve refs — inline all $ref pointers so the spec is self-contained
2. Schemas — convert OpenAPI schema objects into IrSchema variants (object, enum, alias, union)
3. Operations — convert each path + method into an IrOperation with typed parameters, request body, and return type
4. Modules — group operations by their first tag into IrModule
5. Info — extract title, description, version, and server URLs

Key types

CodeGenerator trait

pub trait CodeGenerator {
    type Config;
    type Error: std::error::Error;
    fn generate(
        &self,
        ir: &IrSpec,
        config: &Self::Config,
    ) -> Result<Vec<GeneratedFile>, Self::Error>;
}

Implement this trait to add a new language or framework target.

Part of oag