Derive Macro ApiResponse

#[derive(ApiResponse)]
{
    // Attributes available to this derive:
    #[oai]
}

Define an OpenAPI response.

Macro parameters

Attribute	Description	Type	Optional
bad_request_handler	Sets a custom bad request handler, it can convert error to the value of the this response type.	string	Y
header	Add an extra header	ExtraHeader	Y
display	When converting a response to an error, the error message comes from the Display trait.	bool	Y

Item parameters

Attribute	description	Type	Optional
status	HTTP status code. If omitted, it is a default response type.	u16	Y
content_type	Specify the content type.	string	Y
actual_type	Specifies the actual response type	string	Y
header	Add an extra header	ExtraHeader	Y

Header parameters

Attribute	description	Type	Optional
deprecated	Header deprecated	String	Y

Extra header parameters

Attribute	description	Type	Optional
name	Header name	String	N
ty	Header type	String	N
description	Header description	String	Y
deprecated	Header deprecated	bool	Y

Example response headers

use poem_openapi::{payload::PlainText, ApiResponse};

#[derive(ApiResponse)]
enum CreateUserResponse {
    #[oai(status = 200)]
    Ok(#[oai(header = "X-Id")] String),
    #[oai(status = 201)]
    OkWithBody(PlainText<String>, #[oai(header = "X-Id")] String),
}

Example extra headers

use poem_openapi::ApiResponse;

#[derive(ApiResponse)]
#[oai(
    header(name = "X-ExtraHeader-1", ty = "String"),
    header(name = "X-ExtraHeader-2", ty = "i32"),
)]
enum CreateUserResponse {
    #[oai(status = 200, header(name = "X-ExtraHeader-3", ty = "f32"))]
    Ok,
}

Example with bad request handler

use poem::Error;
use poem_openapi::{payload::PlainText, ApiResponse};

#[derive(ApiResponse)]
#[oai(bad_request_handler = "bad_request_handler")]
enum CreateUserResponse {
    /// Returns when the user is successfully created.
    #[oai(status = 200)]
    Ok,
    /// Returns when the user already exists.
    #[oai(status = 409)]
    UserAlreadyExists,
    /// Returns when the request parameters is incorrect.
    #[oai(status = 400)]
    BadRequest(PlainText<String>),
}

// Convert error to `CreateUserResponse::BadRequest`.
fn bad_request_handler(err: Error) -> CreateUserResponse {
    CreateUserResponse::BadRequest(PlainText(format!("error: {}", err.to_string())))
}

Example as an error type

use poem::Error;
use poem_openapi::{payload::{PlainText, Json}, ApiResponse, Object, OpenApi};

#[derive(Object)]
struct CreateUserRequest {
    username: String,
    nickname: String,
    email: String,
}

#[derive(ApiResponse)]
enum CreateUserResponse {
    /// Returns when the user is successfully created.
    #[oai(status = 200)]
    Ok,
}

#[derive(ApiResponse)]
enum CreateUserResponseError {
    /// Returns when the user already exists.
    #[oai(status = 409)]
    UserAlreadyExists,
    /// Returns when the request parameters is incorrect.
    #[oai(status = 400)]
    BadRequest(PlainText<String>),
}

struct UserApi;

#[OpenApi]
impl UserApi {
    /// Create a new user.
    #[oai(path = "/user", method = "post")]
    async fn create(
        &self,
        user: Json<CreateUserRequest>,
    ) -> Result<CreateUserResponse, CreateUserResponseError> {
        todo!()
    }
}