openapi-trait-axum

Axum-specific procedural macro backend for openapi-trait.

This crate is not intended for direct use. In normal projects, depend on openapi-trait and use the re-exported attribute macro:

#[openapi_trait::axum("openapi/petstore.yaml")]
pub mod petstore {}

What it generates

Given an annotated mod, the macro reads an OpenAPI document at compile time and replaces the module contents with:

• serde-derived Rust structs for components/schemas
• {OperationId}Request structs for path, query, header, and body inputs
• {OperationId}Response enums implementing axum::response::IntoResponse
• A {ModName}Api<S = ()> trait with one method per operationId
• A router() helper that builds an axum::Router<S> for the implementation

The generated trait name comes from the annotated module name, so mod petstore {} produces petstore::PetstoreApi.

Path resolution

The macro resolves the OpenAPI file path relative to CARGO_MANIFEST_DIR and uses include_str! so Cargo recompiles the crate when the spec changes.

Errors

Macro expansion fails at compile time when:

• the OpenAPI file cannot be read
• the document cannot be parsed as OpenAPI YAML or JSON
• an operation is missing an operationId

Crate role

This crate exists so the public openapi-trait crate can keep a small, ergonomic surface while the axum-specific code generation stays isolated.