Crate utoipa

Expand description

Want to have your API documented with OpenAPI? But you dont want to see the trouble with manual yaml or json tweaking? Would like it to be so easy that it would almost be like utopic? Don’t worry utoipa is just there to fill this gap. It aims to do if not all then the most of heavy lifting for you enabling you to focus writing the actual API logic instead of documentation. It aims to be minimal, simple and fast. It uses simple proc macros which you can use to annotate your code to have items documented.

Utoipa crate provides autogenerated OpenAPI documentation for Rust REST APIs. It treats code first appoach as a first class citizen and simplifies API documentation by providing simple macros for generating the documentation from your code.

It also contains Rust types of OpenAPI spec allowing you to write the OpenAPI spec only using Rust if autogeneration is not your flavor or does not fit your purpose.

Long term goal of the library is to be the place to go when OpenAPI documentation is needed in Rust codebase.

What’s up with the word play?

The name comes from words utopic and api where uto is the first three letters of utopic and the ipa is api reversed.

Features

default Default enabled features are json.
json Enables serde_json what allow to use json values in OpenAPI specification values. Thus is enabled by default.
swagger_ui Enables the embedded Swagger UI to view openapi api documentation.
actix-web Enables actix-web integration with pre-configured SwaggerUI service factory allowing users to use the Swagger UI without a hazzle.
actix_extras Enhances actix-web intgration with being able to parse some documentation from actix web macro attributes and types.
debug Add extra traits such as debug traits to openapi definitions and elsewhere.

Install

Add minimal dependency declaration to Cargo.toml.

[dependencies]
utoipa = "0.1.0.beta.0"

To enable more features such as use of swagger together with actix-web framework you could define the dependency as follows.

[dependencies]
utoipa = { version = "0.1.0.beta.0", features = ["swagger_ui", "actix-web", "actix_extras"] }

Examples

Create a struct or it could be an enum also. Add Component derive macro to it so it can be registered as a component in openapi schema.

use utoipa::Component;
#[derive(Component)]
struct Pet {
   id: u64,
   name: String,
   age: Option<i32>,
}

Create an handler that would handle your business logic and add path proc attribute macro over it.

mod pet_api {
    /// Get pet by id
    ///
    /// Get pet from database by pet id  
    #[utoipa::path(
        get,
        path = "/pets/{id}"
        responses = [
            (status = 200, description = "Pet found succesfully", body = Pet),
            (status = 404, description = "Pet was not found")
        ],
        params = [
            ("id" = u64, path, description = "Pet database id to get Pet for"),
        ]
    )]
    async fn get_pet_by_id(pet_id: u64) -> Pet {
        Pet {
            id: pet_id,
            age: None,
            name: "lightning".to_string(),
        }
    }
}

Tie the component and the above api to the openapi schema with following OpenApi derive proc macro.

use utoipa::OpenApi;
use crate::Pet;

#[derive(OpenApi)]
#[openapi(handlers = [pet_api::get_pet_by_id], components = [Pet])]
struct ApiDoc;

println!("{}", ApiDoc::openapi().to_pretty_json().unwrap());

If you have swagger_ui and the actix-web features enabled you can display the openapi documentation as easily as follows:

HttpServer::new(move || {
        App::new()
            .service(
                SwaggerUi::new("/swagger-ui/{_:.*}")
                    .with_url("/api-doc/openapi.json", ApiDoc::openapi()),
            )
    })
    .bind(format!("{}:{}", Ipv4Addr::UNSPECIFIED, 8989))?
    .run()
    .await