Struct NoneAsEmptyString

pub struct NoneAsEmptyString;

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.

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

impl<'de, Str> DeserializeAs<'de, Option<Str>> for NoneAsEmptyString

where Str: FromStr, Str::Err: Display,

fn deserialize_as<D>(deserializer: D) -> Result<Option<Str>, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> SerializeAs<Option<T>> for NoneAsEmptyString

where T: Display,

fn serialize_as<S>(source: &Option<T>, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.