serde-value

serde-cw-value provides a way to capture serialization value trees for later processing. Crate is designed to work with CosmWasm smart contracts, in particular - it errors early when any floating-point types are processed. This is for of serde-value.

Usage

Add the library to the project with cargo add:

cargo add serde-cw-value

Then you can deserialize any serde source to intermediate serde_cw_value::Value representing any structure deserializable by serde. For example you can deserialize arbitrary Json without knowing it's exact structure:

const json: &str = r#"{ "field": "value" }"#;

fn main() {
    let value = serde_json_wasm::from_str(json).unwrap();

    let Value::Map(m) = value else { unreachable!() };
    let v = m.get(&Value::String("field".to_owned())).unwrap();
}

This might be usefull for example when smart contract is forwarding a Json received in the message, but not knowing it full structure. This will verify that underlying data is a proper JSON, and also it allow you to figure out its structure.

It is also possible to deserialize the Value further to a proper structure:

const json: &str = r#"{ "field": "value" }"#;

#[derive(Deserialize)]
struct Data {
    field: String,
}

fn main() {
    let value = serde_json_wasm::from_str(json).unwrap();
    let data: Data = value.deserialize_into();
}

It is always better to deserialize directly to final structure if possible, but there are some cases, when deserialization has to be delayed. Also the Value type is implementing Clone so it is possible to deserialize data to Value, and then deserialize it to final type keeping the intermediate reprezentation for future.

Finally, as Value also implements Serialize it is possible to transcribe one format to another using this, without any knowledge of the internal data, by first deserializing original format to Value, and then serializing it back to the new format.