pub struct DisplayFromStr;
Expand description

De/Serialize using Display and FromStr implementation

This allows deserializing a string as a number. It can be very useful for serialization formats like JSON, which do not support integer numbers and have to resort to strings to represent them.

Another use case is types with Display and FromStr implementations, but without serde support, which can be found in some crates.

If you control the type you want to de/serialize, you can instead use the two derive macros, SerializeDisplay and DeserializeFromStr. They properly implement the traits Serialize and Deserialize such that user of the type no longer have to use the serde_as system.

The same functionality is also available as serde_with::rust::display_fromstr compatible with serde’s with-annotation.

Examples

#[serde_as]
#[derive(Deserialize, Serialize)]
struct A {
    #[serde_as(as = "DisplayFromStr")]
    mime: mime::Mime,
    #[serde_as(as = "DisplayFromStr")]
    number: u32,
}

let v: A = serde_json::from_value(json!({
    "mime": "text/plain",
    "number": "159",
})).unwrap();
assert_eq!(mime::TEXT_PLAIN, v.mime);
assert_eq!(159, v.number);

let x = A {
    mime: mime::STAR_STAR,
    number: 777,
};
assert_eq!(json!({ "mime": "*/*", "number": "777" }), serde_json::to_value(&x).unwrap());

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Returns the “default value” for a type. Read more

Deserialize this value from the given Serde deserializer.

Serialize this value into the given Serde serializer.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.