Struct serde_with::TryFromInto
source · [−]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
sourceimpl<T: Clone> Clone for TryFromInto<T>
impl<T: Clone> Clone for TryFromInto<T>
sourcefn clone(&self) -> TryFromInto<T>
fn clone(&self) -> TryFromInto<T>
Returns a copy of the value. Read more
1.0.0 · sourcefn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
sourceimpl<T: Debug> Debug for TryFromInto<T>
impl<T: Debug> Debug for TryFromInto<T>
sourceimpl<T: Default> Default for TryFromInto<T>
impl<T: Default> Default for TryFromInto<T>
sourcefn default() -> TryFromInto<T>
fn default() -> TryFromInto<T>
Returns the “default value” for a type. Read more
sourceimpl<'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>,
sourcefn deserialize_as<D>(deserializer: D) -> Result<T, D::Error> where
D: Deserializer<'de>,
fn deserialize_as<D>(deserializer: D) -> Result<T, D::Error> where
D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer.
sourceimpl<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,
sourcefn serialize_as<S>(source: &T, serializer: S) -> Result<S::Ok, S::Error> where
S: Serializer,
fn serialize_as<S>(source: &T, serializer: S) -> Result<S::Ok, S::Error> where
S: Serializer,
Serialize this value into the given Serde serializer.
impl<T: Copy> Copy for TryFromInto<T>
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
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more