#serde-yaml #serde #serde-derive

serde_yml

A robust Rust library that simplifies the serialization and deserialization of Rust data structures to and from YAML format using the widely-used Serde framework

11 releases

new 0.0.11 Jul 21, 2024
0.0.10 May 30, 2024
0.0.4 Apr 3, 2024
0.0.2 Mar 29, 2024

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Used in 28 crates (25 directly)

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Serde YML logo

Serde YML (a fork of Serde YAML)

GitHub Crates.io Docs.rs Codecov Build Status

A Rust library for using the Serde serialization framework with data in YAML file format. This project, has been renamed to Serde YML to avoid confusion with the original Serde YAML crate which is now archived and no longer maintained.

Credits and Acknowledgements

This library is a continuation of 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 and does not intend to replace the original serde-yaml crate.

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 as well as looking at the features and improvements offered by other YAML libraries in the Rust ecosystem.

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.

Dependency

[dependencies]
serde = "1.0"
serde_yml = "0.0.11"

Release notes are available under GitHub releases.

Using Serde YML

API documentation is available in rustdoc form but the general idea is:

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(())
}

Examples

Serde YML provides a set of comprehensive examples. 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:

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:

Serializing and Deserializing Structs

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.

Serializing and Deserializing Enums

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.

Serializing and Deserializing Optional Fields

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.

Serializing and Deserializing a HashMap

use std::collections::HashMap;
use serde_yml;

fn main() -> Result<(), serde_yml::Error> {
    let mut map = HashMap::new();
    map.insert("name".to_string(), "John".to_string());
    map.insert("age".to_string(), "30".to_string());

    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.

Serializing and Deserializing Custom Structs

use serde::{Serialize, Deserialize};
use serde_yml;

#[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.

Using Serde derive

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};
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 };

    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};
use serde_yml;

#[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.

Serializing and Deserializing Enums with Custom Serialization and Deserialization

use serde::{Deserialize, Serialize};
use serde::de::{self, Deserializer, MapAccess, Visitor};
use serde::ser::{SerializeMap, Serializer};
use std::fmt;
use serde_yml;

#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum MyEnum {
    Variant1(String),
    Variant2 { field: i32 },
}

#[derive(PartialEq, Debug)]
struct MyStruct {
    field: MyEnum,
}

// Include custom Serialize and Deserialize implementations for MyStruct here
// ...

fn main() -> Result<(), serde_yml::Error> {
    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);

    Ok(())
}

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.

Serializing and Deserializing Optional Enums

use serde::{Deserialize, Serialize};
use serde_yml;
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() -> Result<(), serde_yml::Error> {
    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);

    Ok(())
}

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.

Serializing and Deserializing Nested Enums

use serde::{Deserialize, Serialize};
use serde_yml;
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() -> Result<(), serde_yml::Error> {
    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);

    Ok(())
}

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.

Serializing and Deserializing Enums with singleton_map_recursive

use serde::{Deserialize, Serialize};
use serde_yml;
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() -> Result<(), serde_yml::Error> {
    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);

    Ok(())
}

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.

Serializing and Deserializing Enums with singleton_map_with and Custom Serialization

use serde::{Deserialize, Serialize};
use serde_yml;
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() -> Result<(), serde_yml::Error> {
    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);

    Ok(())
}

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.

Serializing and Deserializing Enums with singleton_map_with

use serde::{Deserialize, Serialize};
use serde_yml;
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() -> Result<(), serde_yml::Error> {
    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);

    Ok(())
}

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.

License

Licensed under either of the Apache License or the MIT license at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Dependencies

~4–13MB
~174K SLoC