relay_log::protocol::value

Function from_value

source
pub fn from_value<T>(value: Value) -> Result<T, Error>
Expand description

Interpret a serde_json::Value as an instance of type T.

§Example

use serde::Deserialize;
use serde_json::json;

#[derive(Deserialize, Debug)]
struct User {
    fingerprint: String,
    location: String,
}

fn main() {
    // The type of `j` is `serde_json::Value`
    let j = json!({
        "fingerprint": "0xF9BA143B95FF6D82",
        "location": "Menlo Park, CA"
    });

    let u: User = serde_json::from_value(j).unwrap();
    println!("{:#?}", u);
}

§Errors

This conversion can fail if the structure of the Value does not match the structure expected by T, for example if T is a struct type but the Value contains something other than a JSON map. It can also fail if the structure is correct but T’s implementation of Deserialize decides that something is wrong with the data, for example required struct fields are missing from the JSON map or some number is too big to fit in the expected primitive type.