Struct JsonString

pub struct JsonString<T = Same>(/* private fields */);

Available on crate feature json only.

Serialize value as string containing JSON

Note: This type is not necessary for normal usage of serde with JSON. It is only required if the serialized format contains a string, which itself contains JSON.

Errors

Serialization can fail if T’s implementation of Serialize decides to fail, or if T contains a map with non-string keys.

Examples

#[serde_as]
#[derive(Deserialize, Serialize)]
struct A {
    #[serde_as(as = "JsonString")]
    other_struct: B,
}
#[derive(Deserialize, Serialize)]
struct B {
    value: usize,
}

let v: A = serde_json::from_str(r#"{"other_struct":"{\"value\":5}"}"#).unwrap();
assert_eq!(5, v.other_struct.value);

let x = A {
    other_struct: B { value: 10 },
};
assert_eq!(
    r#"{"other_struct":"{\"value\":10}"}"#,
    serde_json::to_string(&x).unwrap()
);

The JsonString converter takes a type argument, which allows altering the serialization behavior of the inner value, before it gets turned into a JSON string.

#[serde_as]
#[derive(Debug, Serialize, Deserialize, PartialEq)]
struct Struct {
    #[serde_as(as = "JsonString<Vec<(JsonString, _)>>")]
    value: BTreeMap<[u8; 2], u32>,
}

let value = Struct {
    value: BTreeMap::from([([1, 2], 3), ([4, 5], 6)]),
};
assert_eq!(
    r#"{"value":"[[\"[1,2]\",3],[\"[4,5]\",6]]"}"#,
    serde_json::to_string(&value).unwrap()
);

Trait Implementations

impl<'de, T, TAs> DeserializeAs<'de, T> for JsonString<TAs>

where TAs: for<'a> DeserializeAs<'a, T>,

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

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T, TAs> SerializeAs<T> for JsonString<TAs>

where TAs: SerializeAs<T>,

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

where S: Serializer,

Serialize this value into the given Serde serializer.