pub struct NoneAsEmptyString;
Expand description

De/Serialize a Option<String> type while transforming the empty string to None

Convert an Option<T> from/to string using FromStr and AsRef<str> implementations. An empty string is deserialized as None and a None vice versa.

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

Examples

#[serde_as]
#[derive(Deserialize, Serialize)]
struct A {
    #[serde_as(as = "NoneAsEmptyString")]
    tags: Option<String>,
}

let v: A = serde_json::from_value(json!({ "tags": "" })).unwrap();
assert_eq!(None, v.tags);

let v: A = serde_json::from_value(json!({ "tags": "Hi" })).unwrap();
assert_eq!(Some("Hi".to_string()), v.tags);

let x = A {
    tags: Some("This is text".to_string()),
};
assert_eq!(json!({ "tags": "This is text" }), serde_json::to_value(&x).unwrap());

let x = A {
    tags: None,
};
assert_eq!(json!({ "tags": "" }), 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.