Struct serde_with::TryFromInto [−][src]
pub struct TryFromInto<T>(_);
Expand description
Serialize value by converting to/from a proxy type with serde support.
This adapter serializes a type O
by converting it into a second type T
and serializing T
.
Deserializing works analogue, by deserializing a T
and then converting into O
.
struct S { #[serde_as(as = "TryFromInto<T>")] value: O, }
For serialization O
needs to be O: TryInto<T> + Clone
.
For deserialization the opposite T: TryInto<O>
is required.
The Clone
bound is required since serialize
operates on a reference but TryInto
implementations on references are uncommon.
In both cases the TryInto::Error
type must implement Display
.
Note: FromInto
is the more specialized version of this adapter which uses the infallible Into
trait instead.
TryFromInto
is strictly more general and can also be used where FromInto
is applicable.
The example shows a use case, when only the deserialization behavior is fallible, but not serializing.
Example
#[derive(Clone, Debug, PartialEq)] enum Boollike { True, False, } impl From<Boollike> for u8 { ... } impl TryFrom<u8> for Boollike { type Error = String; fn try_from(v: u8) -> Result<Self, Self::Error> { match v { 0 => Ok(Boollike::False), 1 => Ok(Boollike::True), _ => Err(format!("Boolikes can only be constructed from 0 or 1 but found {}", v)) } } } #[serde_as] #[derive(Deserialize, Serialize)] struct Data { #[serde_as(as = "TryFromInto<u8>")] b: Boollike, } let data = Data { b: Boollike::True, }; // Define our expected JSON form let j = json!({ "b": 1, }); // Ensure serialization and deserialization produce the expected results assert_eq!(j, serde_json::to_value(&data).unwrap()); assert_eq!(data, serde_json::from_value(j).unwrap()); // Numbers besides 0 or 1 should be an error let j = json!({ "b": 2, }); assert_eq!("Boolikes can only be constructed from 0 or 1 but found 2", serde_json::from_value::<Data>(j).unwrap_err().to_string());
Trait Implementations
Returns the “default value” for a type. Read more
impl<'de, T, U> DeserializeAs<'de, T> for TryFromInto<U> where
U: TryInto<T>,
<U as TryInto<T>>::Error: Display,
U: Deserialize<'de>,
impl<'de, T, U> DeserializeAs<'de, T> for TryFromInto<U> where
U: TryInto<T>,
<U as TryInto<T>>::Error: Display,
U: Deserialize<'de>,
Deserialize this value from the given Serde deserializer.
impl<T, U> SerializeAs<T> for TryFromInto<U> where
T: TryInto<U> + Clone,
<T as TryInto<U>>::Error: Display,
U: Serialize,
impl<T, U> SerializeAs<T> for TryFromInto<U> where
T: TryInto<U> + Clone,
<T as TryInto<U>>::Error: Display,
U: Serialize,
Serialize this value into the given Serde serializer.
Auto Trait Implementations
impl<T> RefUnwindSafe for TryFromInto<T> where
T: RefUnwindSafe,
impl<T> Send for TryFromInto<T> where
T: Send,
impl<T> Sync for TryFromInto<T> where
T: Sync,
impl<T> Unpin for TryFromInto<T> where
T: Unpin,
impl<T> UnwindSafe for TryFromInto<T> where
T: UnwindSafe,
Blanket Implementations
Mutably borrows from an owned value. Read more