Return binary in API

[wangjia184]

Hi

I want to implement an API to return an image as raw binary. Content-type should be image/png .
So when this API is opened in web browser, the image is presented.

After reading the example https://github.com/juhaku/utoipa/blob/d020f92a0446adc7e99999aa9e1be63e95728fbb/examples/rocket-todo/src/main.rs, I still don't find a way.

The IntoResponses and ToResponse traits seems does not allow to return raw binary body?

[juhaku]

It should be possible, though there are no examples for it unfortunately. E.g. for OpenApi 3.0 you can do something like this.

#[derive(ToSchema)]
#[schema(format = Binary, value_type = String)]
struct MyFile(Vec<u8>);

#[utoipa::path(
   get,
   path = "/my-file",
   responses(
       (status = 200, description = "My file", content_type = "image/png", body = MyFile),
   )
)]
fn handler() {}

This will change a bit for OpenApi 3.1 since there are specific attributes that can be set like contentEncoding and contentMediaType.

Relevant link for what is going to change in utoipa 5.0.0 https://www.openapis.org/blog/2021/02/16/migrating-from-openapi-3-0-to-3-1-0