Custom de/serialization functions for Rust's serde
This crate provides custom de/serialization helpers to use in combination with serde's with-annotation and with the improved serde_as
-annotation.
Some common use cases are:
- De/Serializing a type using the
Display
andFromStr
traits, e.g., foru8
,url::Url
, ormime::Mime
. CheckDisplayFromStr
orserde_with::rust::display_fromstr
for details. - Skip serializing all empty
Option
types with#[skip_serializing_none]
. - Apply a prefix to each field name of a struct, without changing the de/serialize implementations of the struct using
with_prefix!
. - Deserialize a comma separated list like
#hash,#tags,#are,#great
into aVec<String>
. Check the documentation forserde_with::rust::StringWithSeparator::<CommaSeparator>
.
Check out the user guide to find out more tips and tricks about this crate.
For further help using this crate you can open a new discussion or ask on users.rust-lang.org. For bugs please open a new issue on Github.
Add this to your Cargo.toml
:
[dependencies.serde_with]
version = "1.6.4"
features = [ "..." ]
The crate contains different features for integration with other common crates. Check the feature flags section for information about all available features.
Annotate your struct or enum to enable the custom de/serializer.
#[serde_as]
#[derive(Deserialize, Serialize)]
struct Foo {
// Serialize with Display, deserialize with FromStr
#[serde_as(as = "DisplayFromStr")]
bar: u8,
}
// This will serialize
Foo {bar: 12}
// into this JSON
{"bar": "12"}
This situation often occurs with JSON, but other formats also support optional fields. If many fields are optional, putting the annotations on the structs can become tedious.
#[skip_serializing_none]
#[derive(Deserialize, Serialize)]
struct Foo {
a: Option<usize>,
b: Option<usize>,
c: Option<usize>,
d: Option<usize>,
e: Option<usize>,
f: Option<usize>,
g: Option<usize>,
}
// This will serialize
Foo {a: None, b: None, c: None, d: Some(4), e: None, f: None, g: Some(7)}
// into this JSON
{"d": 4, "g": 7}
This example is mainly supposed to highlight the flexibility of the serde_as
-annotation compared to serde's with-annotation.
More details about serde_as
can be found in the user guide.
#[serde_as]
#[derive(Deserialize, Serialize)]
struct Foo {
// Serialize them into a list of number as seconds
#[serde_as(as = "Vec<DurationSeconds>")]
durations: Vec<Duration>,
// We can treat a Vec like a map with duplicates.
// JSON only allows string keys, so convert i32 to strings
// The bytes will be hex encoded
#[serde_as(as = "BTreeMap<DisplayFromStr, Hex>")]
bytes: Vec<(i32, Vec<u8>)>,
}
// This will serialize
Foo {
durations: vec![Duration::new(5, 0), Duration::new(3600, 0), Duration::new(0, 0)],
bytes: vec![
(1, vec![0, 1, 2]),
(-100, vec![100, 200, 255]),
(1, vec![0, 111, 222]),
],
}
// into this JSON
{
"durations": [5, 3600, 0],
"bytes": {
"1": "000102",
"-100": "64c8ff",
"1": "006fde"
}
}
Licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.