Struct serde_with::DefaultOnNull [−][src]
pub struct DefaultOnNull<T = Same>(_);
Deserialize Default
from null
values
Instead of erroring on null
values, it simply deserializes the Default
variant of the type.
During serialization this wrapper does nothing.
The serialization behavior of the underlying type is preserved.
The type must implement Default
for this conversion to work.
The same functionality is also available as serde_with::rust::default_on_null
compatible with serde’s with-annotation.
Examples
#[serde_as] #[derive(Deserialize, Debug)] struct A { #[serde_as(deserialize_as = "DefaultOnNull")] value: u32, } let a: A = serde_json::from_str(r#"{"value": 123}"#).unwrap(); assert_eq!(123, a.value); // null values are deserialized into the default, here 0 let a: A = serde_json::from_str(r#"{"value": null}"#).unwrap(); assert_eq!(0, a.value);
DefaultOnNull
can be combined with other conversion methods.
In this example we deserialize a Vec
, each element is deserialized from a string.
If we encounter null, then we get the default value of 0.
#[serde_as] #[derive(Serialize, Deserialize)] struct C { #[serde_as(as = "Vec<DefaultOnNull<DisplayFromStr>>")] value: Vec<u32>, }; let c: C = serde_json::from_value(json!({ "value": ["1", "2", null, null, "5"] })).unwrap(); assert_eq!(vec![1, 2, 0, 0, 5], c.value);
Trait Implementations
impl<T: Clone> Clone for DefaultOnNull<T>
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impl<T: Clone> Clone for DefaultOnNull<T>
[src]fn clone(&self) -> DefaultOnNull<T>
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fn clone(&self) -> DefaultOnNull<T>
[src]Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0[src]
fn clone_from(&mut self, source: &Self)
1.0.0[src]Performs copy-assignment from source
. Read more
impl<T: Debug> Debug for DefaultOnNull<T>
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impl<T: Debug> Debug for DefaultOnNull<T>
[src]impl<T: Default> Default for DefaultOnNull<T>
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impl<T: Default> Default for DefaultOnNull<T>
[src]fn default() -> DefaultOnNull<T>
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fn default() -> DefaultOnNull<T>
[src]Returns the “default value” for a type. Read more
impl<'de, T, U> DeserializeAs<'de, T> for DefaultOnNull<U> where
U: DeserializeAs<'de, T>,
T: Default,
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impl<'de, T, U> DeserializeAs<'de, T> for DefaultOnNull<U> where
U: DeserializeAs<'de, T>,
T: Default,
[src]fn deserialize_as<D>(deserializer: D) -> Result<T, D::Error> where
D: Deserializer<'de>,
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fn deserialize_as<D>(deserializer: D) -> Result<T, D::Error> where
D: Deserializer<'de>,
[src]Deserialize this value from the given Serde deserializer.
impl<T, U> SerializeAs<T> for DefaultOnNull<U> where
U: SerializeAs<T>,
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impl<T, U> SerializeAs<T> for DefaultOnNull<U> where
U: SerializeAs<T>,
[src]fn serialize_as<S>(source: &T, serializer: S) -> Result<S::Ok, S::Error> where
S: Serializer,
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fn serialize_as<S>(source: &T, serializer: S) -> Result<S::Ok, S::Error> where
S: Serializer,
[src]Serialize this value into the given Serde serializer.
impl<T: Copy> Copy for DefaultOnNull<T>
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Auto Trait Implementations
impl<T> RefUnwindSafe for DefaultOnNull<T> where
T: RefUnwindSafe,
T: RefUnwindSafe,
impl<T> Send for DefaultOnNull<T> where
T: Send,
T: Send,
impl<T> Sync for DefaultOnNull<T> where
T: Sync,
T: Sync,
impl<T> Unpin for DefaultOnNull<T> where
T: Unpin,
T: Unpin,
impl<T> UnwindSafe for DefaultOnNull<T> where
T: UnwindSafe,
T: UnwindSafe,
Blanket Implementations
impl<T> BorrowMut<T> for T where
T: ?Sized,
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impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]pub fn borrow_mut(&mut self) -> &mut T
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pub fn borrow_mut(&mut self) -> &mut T
[src]Mutably borrows from an owned value. Read more
impl<T> ToOwned for T where
T: Clone,
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impl<T> ToOwned for T where
T: Clone,
[src]type Owned = T
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn to_owned(&self) -> T
[src]Creates owned data from borrowed data, usually by cloning. Read more
pub fn clone_into(&self, target: &mut T)
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pub fn clone_into(&self, target: &mut T)
[src]🔬 This is a nightly-only experimental API. (toowned_clone_into
)
recently added
Uses borrowed data to replace owned data, usually by cloning. Read more