How can I declare additionalProperties: {} on a component?

[Ryan-DL]

I need to declare a free form object similar to this on a type on a schema. (https://swagger.io/docs/specification/data-models/data-types/ example stolen from the docs)

type: object
additionalProperties: {}

How can I declare this in a struct? I was thinking something like this.

#[derive(Debug, Serialize, Deserialize, Component)]
pub struct SomeComponent {
    #[component(value_type = Object)]
    pub values: Value,
}

Thanks in advance 👍

[juhaku]

Hi,

Currently in latest release 1.1.0 there is basically no support for this. But in master branch there is support for this which can be then achieved as follows:

#[derive(Debug, Serialize, Deserialize, ToSchema)]
pub struct SomeComponent {
    #[schema(value_type = Any)]
    pub values: Value,
}

This will be available in new 2.0.0 version once released. The syntax #[schema(value_type = Any)] makes the value behave like an arbitrary object rendering it as type: object within the the OpenAPI spec.

In current release 1.1.0 the value_type does only support primitive type conversions.

[juhaku]

The additionalProperties: {} will only be used when the type rendered is a map to the item type of the map entry and cannot be defined currently manually.

[willbuckner]

Hmm, how do we specifically require that it's an object though? Any implied any type, for example, an int would be valid. One idea might be to at least allow manually specifying the OpenAPI spec type string. As it is, our docs are incorrect without being able to require an object specifically.

[juhaku]

Well the idea behind the Any is exactly that. Any is anything thus not any specifically declared type.

One idea might be to at least allow manually specifying the OpenAPI spec type string

I'm not a fan for this. Stringly typed APIs are bad and exactly the reason why we use Rust so we can leverage the undisputed type system it offers. If we would offer users to write the type in string form it would allow users to specify pretty much anything even incorrect value. Unless the content of the string was validated but how it would then be different from the type format of the possible value.

However I changed the Any to an Object which would follow the OpenAPI spec more closely. #256