序列化未实现序列化的外部crate枚举的vec [英] Serialize vec of external crate enum which doesn't implement serialization
问题描述
我使用带有未实现序列化的枚举的外部板条箱,并且我想在将包含此枚举的Vec的struct中使用它,并有可能反序列化此结构。基于 serde文档我在下面的代码中创建
I use external crate with enum which does not implement serialization, and I want to use it in struct which will contain Vec of of this enum and have possibility de/serialize this struct. Based on serde documentation I created below code
use serde::{Serialize, Deserialize};
#[derive(Debug, PartialEq, Eq)]
enum ExternalCrateColor {
Red,
Green,
Blue
}
#[derive(Debug, Serialize, Deserialize)]
#[serde(remote = "ExternalCrateColor")]
enum LocalColor {
Red,
Green,
Blue
}
#[derive(Debug, Serialize, Deserialize)]
struct Hue {
#[serde(with = "LocalColor")]
color: ExternalCrateColor
}
fn main() {
let tones = Hue { color: ExternalCrateColor::Blue };
let serialized = serde_json::to_string(&tones).unwrap();
println!("serialized = {}", serialized);
let deserialized: Hue = serde_json::from_str(&serialized).unwrap();
if deserialized.color == ExternalCrateColor::Blue {
println!("Blue tones");
}
}
但我想要的就是包含外部CrateColor Vec的色相结构:
But what I want is to have Hue struct to contain Vec of ExternalCrateColor:
struct Hue {
#[serde(with = "LocalColor")]
colors: Vec<ExternalCrateColor>
}
,它不起作用,因为在这种情况下,反序列化要求使用单个ExternalCrateColor。
and it does not works because de/serialization expect in this case single ExternalCrateColor. How to make it work?
推荐答案
我认为您无法使用serde的远程类型功能来完成这项工作,但您可以先定义一个转换来实现:
I don't think you can make this work using the remote-type feature of serde, but you can do it by first defining a conversion:
fn to_local(color: &ExternalCrateColor) -> LocalColor {
match color {
ExternalCrateColor::Red => LocalColor::Red,
ExternalCrateColor::Green => LocalColor::Green,
ExternalCrateColor::Blue => LocalColor::Blue,
}
}
fn to_external(color: &LocalColor) -> ExternalCrateColor {
match color {
LocalColor::Red => ExternalCrateColor::Red,
LocalColor::Green => ExternalCrateColor::Green,
LocalColor::Blue => ExternalCrateColor::Blue,
}
}
使用这些转换,您可以像这样实现它:
Using these conversions, you can implement it like this:
fn color_vec_ser<S: Serializer>(
vec: &Vec<ExternalCrateColor>,
serializer: S
) -> Result<S::Ok, S::Error> {
// First convert the vector into a Vec<LocalColor>.
let vec2: Vec<LocalColor> = vec.iter().map(to_local).collect();
// Instead of serializing Vec<ExternalCrateColor>, we serialize Vec<LocalColor>.
vec2.serialize(serializer)
}
fn color_vec_deser<'de, D: Deserializer<'de>>(
deserializer: D
) -> Result<Vec<ExternalCrateColor>, D::Error> {
// Deserialize as if it was a Vec<LocalColor>.
let vec: Vec<LocalColor> = Deserialize::deserialize(deserializer)?;
// Convert it into an Vec<ExternalCrateColor>
Ok(vec.iter().map(to_external).collect())
}
#[derive(Debug, Serialize, Deserialize)]
struct Hue {
#[serde(serialize_with = "color_vec_ser")]
#[serde(deserialize_with = "color_vec_deser")]
colors: Vec<ExternalCrateColor>
}
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