Serde YML
is a Rust library that simplifies YAML serialization and deserialization using the popular Serde framework. It provides a convenient and efficient way to convert Rust data structures to YAML format and vice versa.
This new library draws inspiration from the excellent work done by David Tolnay and the maintainers of the serde-yaml library. While Serde YML started as a fork of serde-yaml, it has now evolved into a separate library with its own goals and direction in mind.
If you are currently using serde-yaml in your projects, we recommend carefully evaluating your requirements and considering the stability and maturity of the original library before migrating to Serde YML.
Finally, I would like to express my sincere gratitude to David Tolnay and the serde-yaml team for their valuable contributions to the Rust community and for inspiring this project.
• Website • Documentation • Report Bug • Request Feature • Contributing Guidelines
- Serialization and deserialization of Rust data structures to/from YAML format
- Support for custom structs and enums using Serde's derive macros
- Handling of YAML's
!tag
syntax for representing enum variants - Direct access to YAML values through the
Value
type and related types likeMapping
andSequence
- Comprehensive error handling with
Error
,Location
, andResult
types - Serialization to YAML using
to_string
andto_writer
functions - Deserialization from YAML using
from_str
,from_slice
, andfrom_reader
functions - Customizable serialization and deserialization behavior using Serde's
#[serde(with = ...)]
attribute - Support for serializing/deserializing enums using a YAML map with a single key-value pair through the
singleton_map
module - Recursive application of
singleton_map
serialization/deserialization to all enums within a data structure using thesingleton_map_recursive
module - Serialization and deserialization of optional enum fields using the
singleton_map_optional
module - Handling of nested enum structures with optional inner enums using the
singleton_map_recursive
module - Customization of serialization and deserialization logic for enums using the
singleton_map_with
module and custom helper functions
This library is compatible with Rust 1.60 and above.
Add the following dependency to your Cargo.toml
file:
[dependencies]
serde_yml = "0.0.5"
Serde YML offers a straightforward and intuitive API for working with YAML data in Rust. Here's a quick example of how to serialize and deserialize a Rust type:
use serde::{Serialize, Deserialize};
#[derive(Serialize, Deserialize)]
struct Point {
x: f64,
y: f64,
}
fn main() -> Result<(), serde_yml::Error> {
let point = Point { x: 1.0, y: 2.0 };
// Serialize to YAML
let yaml = serde_yml::to_string(&point)?;
assert_eq!(yaml, "x: 1.0\ny: 2.0\n");
// Deserialize from YAML
let deserialized_point: Point = serde_yml::from_str(&yaml)?;
assert_eq!(point, deserialized_point);
Ok(())
}
Serde YML provides a set of comprehensive examples to demonstrate its usage and capabilities. You can find them in the examples
directory of the project.
To run the examples, clone the repository and execute the following command in your terminal from the project root directory:
cargo run --example example
The examples cover various scenarios, including serializing and deserializing structs, enums, optional fields, custom structs, and more.
Here are a few notable examples:
use serde::{Serialize, Deserialize};
use serde_yml;
#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct Point {
x: f64,
y: f64,
}
fn main() -> Result<(), serde_yml::Error> {
let point = Point { x: 1.0, y: 2.0 };
// Serialize to YAML
let yaml = serde_yml::to_string(&point)?;
assert_eq!(yaml, "x: 1.0\ny: 2.0\n");
// Deserialize from YAML
let deserialized_point: Point = serde_yml::from_str(&yaml)?;
assert_eq!(point, deserialized_point);
Ok(())
}
This example demonstrates how to serialize and deserialize a simple struct Point
to and from YAML using the serde_yml
crate.
use serde::{Serialize, Deserialize};
use serde_yml;
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum Shape {
Rectangle { width: u32, height: u32 },
Circle { radius: f64 },
Triangle { base: u32, height: u32 },
}
fn main() -> Result<(), serde_yml::Error> {
let shapes = vec![
Shape::Rectangle { width: 10, height: 20 },
Shape::Circle { radius: 5.0 },
Shape::Triangle { base: 8, height: 12 },
];
// Serialize to YAML
let yaml = serde_yml::to_string(&shapes)?;
println!("Serialized YAML:\n{}", yaml);
// Deserialize from YAML
let deserialized_shapes: Vec<Shape> = serde_yml::from_str(&yaml)?;
assert_eq!(shapes, deserialized_shapes);
Ok(())
}
This example demonstrates how to serialize and deserialize an enum Shape
(with struct variants) to and from YAML using the serde_yml
crate.
use serde::{Serialize, Deserialize};
use serde_yml;
#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct User {
name: String,
age: Option<u32>,
#[serde(default)]
is_active: bool,
}
fn main() -> Result<(), serde_yml::Error> {
let user = User {
name: "John".to_string(),
age: Some(30),
is_active: true,
};
// Serialize to YAML
let yaml = serde_yml::to_string(&user)?;
println!("Serialized YAML:\n{}", yaml);
// Deserialize from YAML
let deserialized_user: User = serde_yml::from_str(&yaml)?;
assert_eq!(user, deserialized_user);
Ok(())
}
This example demonstrates how to serialize and deserialize a struct User
with an optional field age
to and from YAML using the serde_yml
crate.
use std::collections::HashMap;
fn main() -> Result<(), serde_yml::Error> {
let mut map = HashMap::new();
map.insert("name".to_string(), &"John");
map.insert("age".to_string(), &"30");
let yaml = serde_yml::to_string(&map)?;
println!("Serialized YAML: {}", yaml);
let deserialized_map: HashMap<String, serde_yml::Value> = serde_yml::from_str(&yaml)?;
println!("Deserialized map: {:?}", deserialized_map);
Ok(())
}
This example demonstrates how to serialize and deserialize a HashMap
to and from YAML using the serde_yml
crate.
use serde::{Serialize, Deserialize};
#[derive(Serialize, Deserialize, Debug)]
struct Person {
name: String,
age: u32,
city: String,
}
fn main() -> Result<(), serde_yml::Error> {
let person = Person {
name: "Alice".to_string(),
age: 25,
city: "New York".to_string(),
};
let yaml = serde_yml::to_string(&person)?;
println!("Serialized YAML: {}", yaml);
let deserialized_person: Person = serde_yml::from_str(&yaml)?;
println!("Deserialized person: {:?}", deserialized_person);
Ok(())
}
This example demonstrates how to serialize and deserialize a custom struct Person
to and from YAML using the serde_yml
crate.
It can also be used with Serde's derive macros to handle structs and enums defined in your program.
Structs serialize in the obvious way:
# use serde_derive::{Serialize, Deserialize};
#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct Point {
x: f64,
y: f64,
}
fn main() -> Result<(), serde_yml::Error> {
let point = Point { x: 1.0, y: 2.0 };
let yaml = serde_yml::to_string(&point)?;
assert_eq!(yaml, "x: 1.0\n'y': 2.0\n");
let deserialized_point: Point = serde_yml::from_str(&yaml)?;
assert_eq!(point, deserialized_point);
Ok(())
}
Enums serialize using YAML's !tag
syntax to identify the variant name.
use serde_derive::{Serialize, Deserialize};
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum Enum {
Unit,
Newtype(usize),
Tuple(usize, usize, usize),
Struct { x: f64, y: f64 },
}
fn main() -> Result<(), serde_yml::Error> {
let yaml = "
- !Newtype 1
- !Tuple [0, 0, 0]
- !Struct {x: 1.0, y: 2.0}
";
let values: Vec<Enum> = serde_yml::from_str(yaml).unwrap();
assert_eq!(values[0], Enum::Newtype(1));
assert_eq!(values[1], Enum::Tuple(0, 0, 0));
assert_eq!(values[2], Enum::Struct { x: 1.0, y: 2.0 });
// The last two in YAML's block style instead:
let yaml = "
- !Tuple
- 0
- 0
- 0
- !Struct
x: 1.0
'y': 2.0
";
let values: Vec<Enum> = serde_yml::from_str(yaml).unwrap();
assert_eq!(values[0], Enum::Tuple(0, 0, 0));
assert_eq!(values[1], Enum::Struct { x: 1.0, y: 2.0 });
// Variants with no data can be written using !Tag or just the string name.
let yaml = "
- Unit # serialization produces this one
- !Unit
";
let values: Vec<Enum> = serde_yml::from_str(yaml).unwrap();
assert_eq!(values[0], Enum::Unit);
assert_eq!(values[1], Enum::Unit);
Ok(())
}
This example demonstrates how to use Serde's derive macros to automatically implement the Serialize
and Deserialize
traits for a struct Point
, and then serialize and deserialize it to and from YAML using the serde_yml
crate.
use serde::{Deserialize, Serialize};
use serde::de::{self, Deserializer, MapAccess, Visitor};
use serde::ser::{SerializeMap, Serializer};
use std::fmt;
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum MyEnum {
Variant1(String),
Variant2 { field: i32 },
}
#[derive(PartialEq, Debug)]
struct MyStruct {
field: MyEnum,
}
// Custom Serialize and Deserialize implementations for MyStruct
// ...
fn main() {
let input = MyStruct {
field: MyEnum::Variant2 { field: 42 },
};
let yaml = serde_yml::to_string(&input).unwrap();
println!("\n✅ Serialized YAML:\n{}", yaml);
let output: MyStruct = serde_yml::from_str(&yaml).unwrap();
println!("\n✅ Deserialized YAML:\n{:#?}", output);
assert_eq!(input, output);
}
This example demonstrates how to use custom Serialize
and Deserialize
implementations for a struct containing an enum field, and how to leverage serde_yml
to serialize and deserialize the struct to and from YAML.
use serde::{Deserialize, Serialize};
use serde_yml::with::singleton_map_optional;
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum OptionalEnum {
Variant1(String),
Variant2 { field: i32 },
}
#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct OptionalStruct {
#[serde(with = "singleton_map_optional")]
field: Option<OptionalEnum>,
}
// ...
fn main() {
let input = OptionalStruct {
field: Some(OptionalEnum::Variant2 { field: 42 }),
};
let yaml = serde_yml::to_string(&input).unwrap();
println!("\n✅ Serialized YAML:\n{}", yaml);
let output: OptionalStruct = serde_yml::from_str(&yaml).unwrap();
println!("\n✅ Deserialized YAML:\n{:#?}", output);
assert_eq!(input, output);
}
This example demonstrates how to use the singleton_map_optional
attribute to serialize and deserialize an Option<Enum>
field as a single YAML mapping entry with the key being the enum variant name.
use serde::{Deserialize, Serialize};
use serde_yml::with::singleton_map_recursive;
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum NestedEnum {
Variant1(String),
Variant2(Option<InnerEnum>),
}
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum InnerEnum {
Inner1(i32),
Inner2(i32),
}
#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct NestedStruct {
#[serde(with = "singleton_map_recursive")]
field: NestedEnum,
}
// ...
fn main() {
let input = NestedStruct {
field: NestedEnum::Variant2(Some(InnerEnum::Inner2(42))),
};
let yaml = serde_yml::to_string(&input).unwrap();
println!("\n✅ Serialized YAML:\n{}", yaml);
let output: NestedStruct = serde_yml::from_str(&yaml).unwrap();
println!("\n✅ Deserialized YAML:\n{:#?}", output);
assert_eq!(input, output);
}
This example demonstrates how to use the singleton_map_recursive
attribute to serialize and deserialize a nested enum structure where one of the enum variants contains an optional inner enum.
use serde::{Deserialize, Serialize};
use serde_yml::with::singleton_map_recursive;
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum MyEnum {
Variant1(String),
Variant2 { field: i32 },
}
#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct MyStruct {
#[serde(with = "singleton_map_recursive")]
field: MyEnum,
}
// ...
fn main() {
let input = MyStruct {
field: MyEnum::Variant2 { field: 42 },
};
let yaml = serde_yml::to_string(&input).unwrap();
println!("\n✅ Serialized YAML:\n{}", yaml);
let output: MyStruct = serde_yml::from_str(&yaml).unwrap();
println!("\n✅ Deserialized YAML:\n{:#?}", output);
assert_eq!(input, output);
}
This example demonstrates how to use the singleton_map_recursive
attribute to serialize and deserialize an enum field as a single YAML mapping entry with the key being the enum variant name.
use serde::{Deserialize, Serialize};
use serde_yml::with::singleton_map_with;
fn custom_serialize<T, S>(
value: &T,
serializer: S,
) -> Result<S::Ok, S::Error>
where
T: Serialize,
S: serde::Serializer,
{
// Custom serialization logic
singleton_map_with::serialize(value, serializer)
}
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum MyEnum {
Variant1(String),
Variant2 { field: i32 },
}
#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct MyStruct {
#[serde(
serialize_with = "custom_serialize",
deserialize_with = "singleton_map_with::deserialize"
)]
field: MyEnum,
}
fn main() {
let input = MyStruct {
field: MyEnum::Variant2 { field: 42 },
};
let yaml = serde_yml::to_string(&input).unwrap();
println!("\n✅ Serialized YAML:\n{}", yaml);
let output: MyStruct = serde_yml::from_str(&yaml).unwrap();
println!("\n✅ Deserialized YAML:\n{:#?}", output);
assert_eq!(input, output);
}
This example demonstrates how to use the singleton_map_with
attribute in combination with a custom serialization function (custom_serialize
) to serialize and deserialize an enum field (MyEnum
) within a struct (MyStruct
).
The custom_serialize
function is used for serialization, while the singleton_map_with::deserialize
function is used for deserialization. This allows for additional customization of the serialization process while still leveraging the singleton_map_with attribute for deserialization.
use serde::{Deserialize, Serialize};
use serde_yml::with::singleton_map_with;
#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum MyEnum {
Variant1(String),
Variant2 { field: i32 },
}
#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct MyStruct {
#[serde(with = "singleton_map_with")]
field: MyEnum,
}
fn main() {
let input = MyStruct {
field: MyEnum::Variant2 { field: 42 },
};
let yaml = serde_yml::to_string(&input).unwrap();
println!("\n✅ Serialized YAML:\n{}", yaml);
let output: MyStruct = serde_yml::from_str(&yaml).unwrap();
println!("\n✅ Deserialized YAML:\n{:#?}", output);
assert_eq!(input, output);
}
This example demonstrates how to use the singleton_map_with
attribute to serialize and deserialize an enum field (MyEnum
) within a struct (MyStruct
). The singleton_map_with
attribute allows for additional customization of the serialization and deserialization process through the use of helper functions.
- When serializing large datasets, consider using
serde_yml::to_writer
to write the YAML output directly to a file or a writer instead of keeping the entire serialized string in memory. - Be cautious when deserializing untrusted YAML input, as it may contain unexpected or malicious data. Always validate and handle the deserialized data appropriately.
- When working with custom structs or enums, ensure that they implement the necessary Serde traits (
Serialize
andDeserialize
) for proper serialization and deserialization. - If you encounter any issues or have questions, refer to the library's documentation and examples for guidance. If the problem persists, consider opening an issue on the library's GitHub repository.
To use Serde YML in your Rust project, add the following to your Cargo.toml
file:
[dependencies]
serde_yml = "0.0.5"
For transparency into our release cycle and in striving to maintain
backward compatibility, serde_yml
follows semantic versioning.
The project is licensed under the terms of both the MIT license and the Apache License (Version 2.0).
We welcome all people who want to contribute. Please see the contributing instructions for more information.
Contributions in any form (issues, pull requests, etc.) to this project must adhere to the Rust's Code of Conduct.
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.
A big thank you to all the awesome contributors of serde_yml for their help and support. A special thank you goes to David Tolnay and his work on Serde YAML for inspiring this project.