Crate serde_with[−][src]
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>
.
Getting Help
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.
Use serde_with
in your Project
Add this to your Cargo.toml
:
[dependencies.serde_with]
version = "1.9.0"
features = [ "..." ]
The crate contains different features for integration with other common crates. Check the feature flags section for information about all available features.
Examples
Annotate your struct or enum to enable the custom de/serializer.
DisplayFromStr
#[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"}
skip_serializing_none
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}
Advanced serde_as
usage
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" } }
Modules
chrono | De/Serialization of chrono types |
de | Module for |
formats | Specify the format and how lenient the deserialization is |
guide |
|
hex | De/Serialization of hexadecimal encoded bytes |
json | De/Serialization of JSON |
rust | De/Serialization for Rust’s builtin and std types |
ser | Module for |
Macros
flattened_maybe | Support deserializing from flattened and non-flattened representation |
serde_conv | Create new conversion adapters from functions |
with_prefix | Serialize with an added prefix on every field name and deserialize by trimming away the prefix. |
Structs
As | Adapter to convert from |
Bytes | Optimized handling of owned and borrowed byte representations. |
BytesOrString | Deserialize from bytes or string |
CommaSeparator | Predefined separator using a single comma |
DefaultOnError | Deserialize value and return |
DefaultOnNull | Deserialize |
DisplayFromStr | |
DurationMicroSeconds | Equivalent to |
DurationMicroSecondsWithFrac | Equivalent to |
DurationMilliSeconds | Equivalent to |
DurationMilliSecondsWithFrac | Equivalent to |
DurationNanoSeconds | Equivalent to |
DurationNanoSecondsWithFrac | Equivalent to |
DurationSeconds | De/Serialize Durations as number of seconds. |
DurationSecondsWithFrac | De/Serialize Durations as number of seconds. |
FromInto | Serialize value by converting to/from a proxy type with serde support. |
NoneAsEmptyString | De/Serialize a |
OneOrMany | Deserialize one or many elements |
PickFirst | Try multiple deserialization options until one succeeds. |
Same | Adapter to convert from |
SpaceSeparator | Predefined separator using a single space |
StringWithSeparator | De/Serialize a delimited collection using |
TimestampMicroSeconds | Equivalent to |
TimestampMicroSecondsWithFrac | Equivalent to |
TimestampMilliSeconds | Equivalent to |
TimestampMilliSecondsWithFrac | Equivalent to |
TimestampNanoSeconds | Equivalent to |
TimestampNanoSecondsWithFrac | Equivalent to |
TimestampSeconds | De/Serialize timestamps as seconds since the UNIX epoch |
TimestampSecondsWithFrac | De/Serialize timestamps as seconds since the UNIX epoch |
TryFromInto | Serialize value by converting to/from a proxy type with serde support. |
Traits
DeserializeAs | A data structure that can be deserialized from any data format supported by Serde, analogue to |
Separator | Separator for string-based collection de/serialization |
SerializeAs | A data structure that can be serialized into any data format supported by Serde, analogue to |
Attribute Macros
serde_as | Convenience macro to use the |
skip_serializing_none | Add |
Derive Macros
DeserializeFromStr | Deserialize value by using it’s |
SerializeDisplay | Serialize value by using it’s |