Struct serde_with::Map

pub struct Map<K, V>(_);

This serializes a list of tuples into a map

Normally, you want to use a HashMap or a BTreeMap when deserializing a map. However, sometimes this is not possible due to type constraints, e.g., if the type implements neither Hash nor Ord. Another use case is deserializing a map with duplicate keys.

Examples

Wrapper does not implement Hash nor Ord, thus prohibiting the use HashMap or BTreeMap. The JSON also contains a duplicate key.

#[serde_as]
#[derive(Debug, Deserialize, Serialize, Default)]
struct S {
    #[serde_as(as = "Map<_, _>")]
    s: Vec<(Wrapper<i32>, String)>,
}

#[derive(Clone, Debug, Serialize, Deserialize)]
#[serde(transparent)]
struct Wrapper<T>(T);

let data = S {
    s: vec![
        (Wrapper(1), "a".to_string()),
        (Wrapper(2), "b".to_string()),
        (Wrapper(3), "c".to_string()),
        (Wrapper(2), "d".to_string()),
    ],
};

let json = r#"{
  "s": {
    "1": "a",
    "2": "b",
    "3": "c",
    "2": "d"
  }
}"#;
assert_eq!(json, serde_json::to_string_pretty(&data).unwrap());

Trait Implementations

impl<'de, K, KAs, V, VAs, const N: usize> DeserializeAs<'de, [(K, V); N]> for Map<KAs, VAs>where KAs: DeserializeAs<'de, K>, VAs: DeserializeAs<'de, V>,

fn deserialize_as<D>(deserializer: D) -> Result<[(K, V); N], D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, K, KAs, V, VAs> DeserializeAs<'de, BTreeSet<(K, V), Global>> for Map<KAs, VAs>where KAs: DeserializeAs<'de, K>, VAs: DeserializeAs<'de, V>, (K, V): Ord,

fn deserialize_as<D>(deserializer: D) -> Result<BTreeSet<(K, V)>, D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, K, KAs, V, VAs> DeserializeAs<'de, BinaryHeap<(K, V)>> for Map<KAs, VAs>where KAs: DeserializeAs<'de, K>, VAs: DeserializeAs<'de, V>, (K, V): Ord,

fn deserialize_as<D>(deserializer: D) -> Result<BinaryHeap<(K, V)>, D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, K, KAs, V, VAs> DeserializeAs<'de, HashSet<(K, V), RandomState>> for Map<KAs, VAs>where KAs: DeserializeAs<'de, K>, VAs: DeserializeAs<'de, V>, (K, V): Eq + Hash,

fn deserialize_as<D>(deserializer: D) -> Result<HashSet<(K, V)>, D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, K, KAs, V, VAs> DeserializeAs<'de, IndexSet<(K, V), RandomState>> for Map<KAs, VAs>where KAs: DeserializeAs<'de, K>, VAs: DeserializeAs<'de, V>, (K, V): Eq + Hash,

fn deserialize_as<D>(deserializer: D) -> Result<IndexSet<(K, V)>, D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, K, KAs, V, VAs> DeserializeAs<'de, LinkedList<(K, V)>> for Map<KAs, VAs>where KAs: DeserializeAs<'de, K>, VAs: DeserializeAs<'de, V>,

fn deserialize_as<D>(deserializer: D) -> Result<LinkedList<(K, V)>, D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, K, KAs, V, VAs> DeserializeAs<'de, Vec<(K, V), Global>> for Map<KAs, VAs>where KAs: DeserializeAs<'de, K>, VAs: DeserializeAs<'de, V>,

fn deserialize_as<D>(deserializer: D) -> Result<Vec<(K, V)>, D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, K, KAs, V, VAs> DeserializeAs<'de, VecDeque<(K, V), Global>> for Map<KAs, VAs>where KAs: DeserializeAs<'de, K>, VAs: DeserializeAs<'de, V>,

fn deserialize_as<D>(deserializer: D) -> Result<VecDeque<(K, V)>, D::Error>where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<K, KAs, V, VAs> SerializeAs<[(K, V)]> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>(source: &[(K, V)], serializer: S) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs, const N: usize> SerializeAs<[(K, V); N]> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>( source: &[(K, V); N], serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs> SerializeAs<BTreeSet<(K, V), Global>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>( source: &BTreeSet<(K, V)>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs> SerializeAs<BinaryHeap<(K, V)>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>( source: &BinaryHeap<(K, V)>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs> SerializeAs<Box<[(K, V)], Global>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>( source: &Box<[(K, V)]>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs, H> SerializeAs<HashSet<(K, V), H>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>, H: ?Sized + Sized,

fn serialize_as<S>( source: &HashSet<(K, V), H>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs, H> SerializeAs<IndexSet<(K, V), H>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>, H: ?Sized + Sized,

fn serialize_as<S>( source: &IndexSet<(K, V), H>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs> SerializeAs<LinkedList<(K, V)>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>( source: &LinkedList<(K, V)>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs> SerializeAs<Option<(K, V)>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>( source: &Option<(K, V)>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs> SerializeAs<Vec<(K, V), Global>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>( source: &Vec<(K, V)>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.

impl<K, KAs, V, VAs> SerializeAs<VecDeque<(K, V), Global>> for Map<KAs, VAs>where KAs: SerializeAs<K>, VAs: SerializeAs<V>,

fn serialize_as<S>( source: &VecDeque<(K, V)>, serializer: S ) -> Result<S::Ok, S::Error>where S: Serializer,

Serialize this value into the given Serde serializer.