Mar*_*cin 1 serialization yaml rust deserialization serde
我有一段serde代码可以实现我想要的功能，但我不喜欢它的实现方式。我正在寻求帮助以了解如何改进它。
use std::any::Any;\n\ntrait Model: std::fmt::Debug + Any {\n fn as_any(&self) -> &dyn Any;\n}\n\nimpl Model for Generator {\n fn as_any(&self) -> &dyn Any {\n self\n }\n}\nimpl Model for Connector {\n fn as_any(&self) -> &dyn Any {\n self\n }\n}\n\n#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]\npub struct Generator {\n id: String,\n #[serde(rename = "sourceID")]\n source_id: String,\n}\n\n#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]\npub struct Connector {\n id: String,\n #[serde(rename = "sourceID")]\n source_id: String,\n}\n\n#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]\n#[serde(tag = "type")]\nenum AllModels {\n Generator(Generator),\n Connector(Connector),\n}\n\nfn main() {\n let data = r#"\n- sourceID: "generator-01"\n id: "connector-01"\n type: "Generator"\n- sourceID: "geneiator-01"\n type: "Connector"\n id: "connector-01"\n"#;\n let p: Vec<Box<dyn Model>> = serde_yaml::from_str::<Vec<AllModels>>(&data)\n .unwrap()\n .into_iter()\n .collect();\n println!("{:?}", p);\n let l = serde_yaml::to_string(&p.into_iter().collect::<Vec<AllModels>>());\n println!("{:?}", l);\n}\n\nimpl std::iter::FromIterator<AllModels> for Vec<Box<dyn Model>> {\n fn from_iter<I: IntoIterator<Item = AllModels>>(iter: I) -> Self {\n let mut v: Vec<Box<dyn Model>> = Vec::new();\n for i in iter {\n match i {\n AllModels::Generator(d) => {\n v.push(Box::new(d));\n }\n AllModels::Connector(d) => {\n v.push(Box::new(d));\n }\n }\n }\n v\n }\n}\n\nimpl std::iter::FromIterator<std::boxed::Box<dyn Model>> for std::vec::Vec<AllModels> {\n fn from_iter<I: IntoIterator<Item = Box<dyn Model>>>(iter: I) -> Self {\n let mut v: Vec<AllModels> = Vec::new();\n for i in iter {\n if let Some(model) = i.as_any().downcast_ref::<Generator>() {\n v.push(AllModels::Generator(model.clone()));\n } else if let Some(model) = i.as_any().downcast_ref::<Connector>() {\n v.push(AllModels::Connector(model.clone()));\n }\n }\n v\n }\n}\n我想要实现的是将 yaml 反/序列化为多个结构之一，根据它type解析的 yaml 中的字段值动态选择应该反序列化到哪个结构。例如
- id: Foo\n source: Bar\n type: Connector\n应该被解析为struct Connector
我想我可以使用枚举表示来处理这个问题，但是，它会产生不需要的副作用 - 默认情况下遵循 yaml：
\n- id: Foo\n source: Bar\n type: Connector\n- id: Foo\n source: Bar\n type: Generator\n将被解析为：
\n[Connector(Connector{...}), Generator(Generator{...})]\n所以我的结构被封装在枚举变体中。为了“解开它”，我想我可以实现FromIterator<AllModels> for Vec<Box<dyn Model>>，多亏了它和类型转换/强制（不确定哪个是正确的词），输出更改为：
[Connector{...}, Generator{...}]\n到目前为止，一切都很好。
\n我在使用此解决方案时遇到的两个问题是：
\nenum AllModels并match武装内部FromIterator实现 - 后者是最困扰我的。我可能可以用宏来做到这一点，但我还没有学会如何编写它们，在这样做之前，我想探索其他可能的解决方案Vec<enum variant>为Vec<struct>我需要执行以下操作：let p: Vec<Box<dyn Model>> = serde_yaml::from_str::<Vec<AllModels>>(&data).unwrap().into_iter().collect();。我希望在没有额外迭代的情况下进行转换我考虑了一些选项，但我不知道如何实现它们......
\n#[serde(from = "FromType")]- 我认为它的工作方式是将我的枚举变量直接强制转换为所需的结构，没有额外的迭代，也没有代码重复。但是，我未能实现它 - Playground。
当我尝试添加from属性时
#[derive(Debug, Clone, Serialize, Deserialize)]\n#[serde(tag = "type")]\nenum AllModels {\n Gene(Generator),\n Connector(Connector),\n}\n编译器会对我大喊大叫
\n \xe2\x9d\xaf cargo r\n Compiling serdeissue v0.1.0 (/sandbox/serdeissue)\nerror[E0277]: the trait bound `Box<dyn Model>: From<AllModels>` is not satisfied\n --> src/main.rs:21:24\n |\n21 | #[derive(Debug, Clone, Serialize, Deserialize)]\n | ^^^^^^^^^ the trait `From<AllModels>` is not implemented for `Box<dyn Model>`\n |\n = help: the following implementations were found:\n <Box<(dyn StdError + \'a)> as From<E>>\n <Box<(dyn StdError + \'static)> as From<&str>>\n <Box<(dyn StdError + \'static)> as From<Cow<\'a, str>>>\n <Box<(dyn StdError + \'static)> as From<std::string::String>>\n and 22 others\n = note: required because of the requirements on the impl of `Into<Box<dyn Model>>` for `AllModels`\n = note: required by `into`\n = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)\n\nerror[E0277]: the trait bound `dyn Model: Serialize` is not satisfied\n --> src/main.rs:21:24\n |\n21 | #[derive(Debug, Clone, Serialize, Deserialize)]\n | ^^^^^^^^^ the trait `Serialize` is not implemented for `dyn Model`\n |\n ::: /home/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.123/src/ser/mod.rs:247:18\n |\n247 | fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>\n | - required by this bound in `serialize`\n |\n = note: required because of the requirements on the impl of `Serialize` for `Box<dyn Model>`\n = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)\n\nerror[E0277]: the trait bound `dyn Model: Deserialize<\'_>` is not satisfied\n --> src/main.rs:21:35\n |\n21 | #[derive(Debug, Clone, Serialize, Deserialize)]\n | ^^^^^^^^^^^ the trait `Deserialize<\'_>` is not implemented for `dyn Model`\n |\n ::: /home/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.123/src/de/mod.rs:539:12\n |\n539 | D: Deserializer<\'de>;\n | ----------------- required by this bound in `_::_serde::Deserialize::deserialize`\n |\n = note: required because of the requirements on the impl of `Deserialize<\'_>` for `Box<dyn Model>`\n = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)\n\nerror[E0277]: the trait bound `AllModels: From<Box<dyn Model>>` is not satisfied\n --> src/main.rs:21:35\n |\n21 | #[derive(Debug, Clone, Serialize, Deserialize)]\n | ^^^^^^^^^^^ the trait `From<Box<dyn Model>>` is not implemented for `AllModels`\n |\n ::: /home/marcin/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:372:1\n |\n372 | pub trait From<T>: Sized {\n | ------------------------ required by this bound in `From`\n |\n = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)\n我的攻击角度如下：使用错误消息复制 Pasteroni-dummy-implementoni 缺失的特征边界：
\nimpl From<AllModels> for Box<dyn Model> {\n fn from(am: AllModels) -> Self {\n Box::new(Generator{id:String::from("arst"),source_id:String::from("arst")})\n }\n}\nimpl Serialize for dyn Model {\n fn serialize(&self) -> Self {\n Box::new(Generator{id:String::from("arst"),source_id:String::from("arst")})\n }\n}\n\nimpl Deserialize<\'_> for dyn Model {}\nimpl From<Box<dyn Model>> for AllModels {\n fn from(dm: Box<dyn Model>) -> Self {\n AllModels::Gene(Generator{id:String::from("arst"),source_id:String::from("arst")})\n }\n}\n但随后会发生这种情况：
\n \xe2\x9d\xaf cargo r\n Compiling serdeissue v0.1.0 (/sandbox/serdeissue)\nerror[E0277]: the size for values of type `(dyn Model + \'static)` cannot be known at compilation time\n --> src/main.rs:75:6\n |\n75 | impl Deserialize<\'_> for dyn Model {}\n | ^^^^^^^^^^^^^^^ doesn\'t have a size known at compile-time\n |\n ::: /home/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.123/src/de/mod.rs:530:29\n |\n530 | pub trait Deserialize<\'de>: Sized {\n | ----- required by this bound in `Deserialize`\n |\n = help: the trait `Sized` is not implemented for `(dyn Model + \'static)`\n对我来说游戏就结束了
\n这似乎是完成这项工作的正确工具，但我在实现它时再次遇到了问题（难怪 - 我不知道我在做什么:)
\nuse erased_serde::{Deserializer, Serializer, serialize_trait_object};\nuse serde::{Serialize, Deserialize};\n\n\n#[derive(Debug, Clone, Serialize, Deserialize)]\npub struct Generator {\n id: String,\n source: String,\n}\n\n#[derive(Debug, Clone, Serialize, Deserialize)]\npub struct Connector {\n id: String,\n source: String,\n}\n\ntrait Model: std::fmt::Debug + erased_serde::Serialize {}\nerased_serde::serialize_trait_object!(Model);\nimpl Model for Generator {}\nimpl Model for Connector {}\n\n#[derive(Debug, Clone, Serialize, Deserialize)]\n#[serde(tag = "type", into = "Box<dyn Model>", from = "Box<dyn Model>")]\nenum AllModels {\n Generator(Generator),\n Connector(Connector),\n}\n\nfn main() {\n let data = r#"\n- source: "generator-01"\n id: "g-01"\n type: "Generator"\n- source: "connector-01"\n type: "Connector"\n id: "c-01"\n"#;\n let p: Vec<Box<dyn Model>> = serde_yaml::from_str(&data).unwrap();\n println!("{:?}", p);\n}\n\n\nimpl From<AllModels> for Box<dyn Model> {\n fn from(am: AllModels) -> Self {\n Box::new(Generator{id:String::from("arst"),source_id:String::from("arst")})\n }\n}\n// impl Serialize for dyn Model {\n// fn serialize(&self) -> Self {\n// Box::new(Generator{id:String::from("arst"),source_id:String::from("arst")})\n// }\n// }\nimpl Deserialize<\'_> for dyn Model {}\nimpl From<Box<dyn Model>> for AllModels {\n fn from(dm: Box<dyn Model>) -> Self {\n AllModels::Generator(Generator{id:String::from("arst"),source_id:String::from("arst")})\n }\n}\n\n// impl std::convert::From<AllModels> for Box<dyn Model> {\n// fn from(m: AllModels) -> Self {\n// Box::new(Generator {source_id: String::from("i"), id: String::from("r")})\n// }\n// }\n\n编译时出现此错误：
\n \xe2\x9d\xaf cargo r\n Compiling serdeissue v0.1.0 (/sandbox/serdeissue)\nwarning: unused imports: `Deserializer`, `Serializer`, `serialize_trait_object`\n --> src/main.rs:1:20\n |\n1 | use erased_serde::{Deserializer, Serializer, serialize_trait_object};\n | ^^^^^^^^^^^^ ^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^\n |\n = note: `#[warn(unused_imports)]` on by default\n\nerror[E0277]: the size for values of type `(dyn Model + \'static)` cannot be known at compilation time\n --> src/main.rs:76:6\n |\n76 | impl Deserialize<\'_> for dyn Model {}\n | ^^^^^^^^^^^^^^^ doesn\'t have a size known at compile-time\n |\n ::: /home/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.123/src/de/mod.rs:530:29\n |\n530 | pub trait Deserialize<\'de>: Sized {\n | ----- required by this bound in `Deserialize`\n |\n = help: the trait `Sized` is not implemented for `(dyn Model + \'static)`\n我认为erased_serde可以帮助解决这个问题，也许确实如此，但我不知道如何实现它。
\n遗憾的是我无法使用typetag板条箱，因为它不支持wasm我需要的编译目标。我不考虑#[serde(serialize_with = "path")]对每个枚举变体使用，因为它使我的问题＃1比目前更糟糕。
我也知道这个问题How to Implement `serde::Serialize` for a boxed Trait object? 但是@dtolnay提供的代码无法编译，我不知道如何修复它
\n\xe2\x9d\xaf cargo r\n Compiling serdeissue v0.1.0 (/sandbox/serdeissue)\nerror[E0603]: module `export` is private\n --> src/main.rs:168:10\n |\n168 | #[derive(Serialize)]\n | ^^^^^^^^^ private module\n |\nnote: the module `export` is defined here\n --> /home/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.123/src/lib.rs:275:5\n |\n275 | use self::__private as export;\n | ^^^^^^^^^^^^^^^^^^^^^^^^^\n\nerror[E0603]: module `export` is private\n --> src/main.rs:173:10\n |\n173 | #[derive(Serialize)]\n | ^^^^^^^^^ private module\n |\nnote: the module `export` is defined here\n --> /home/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.123/src/lib.rs:275:5\n |\n275 | use self::__private as export;\n | ^^^^^^^^^^^^^^^^^^^^^^^^^\n\nerror[E0603]: module `export` is private\n --> src/main.rs:179:10\n |\n179 | #[derive(Serialize)]\n | ^^^^^^^^^ private module\n |\nnote: the module `export` is defined here\n --> /home/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.123/src/lib.rs:275:5\n |\n275 | use self::__private as export;\n | ^^^^^^^^^^^^^^^^^^^^^^^^^\n\nerror[E0603]: module `export` is private\n --> src/main.rs:184:10\n |\n184 | #[derive(Serialize)]\n | ^^^^^^^^^ private module\n |\nnote: the module `export` is defined here\n --> /home/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/serde-1.0.123/src/lib.rs:275:5\n |\n275 | use self::__private as export;\n | ^^^^^^^^^^^^^^^^^^^^^^^^^\n\nwarning: trait objects without an explicit `dyn` are deprecated\n --> src/main.rs:176:22\n |\n176 | widgets: Vec<Box<WidgetTrait>>,\n | ^^^^^^^^^^^ help: use `dyn`: `dyn WidgetTrait`\n |\n = note: `#[warn(bare_trait_objects)]` on by default\n看起来我正在寻找的功能正在等待在这里实现： https: //github.com/serde-rs/serde/issues/1402
\n还有这个问题https://github.com/serde-rs/serde/issues/1350建议手动解串器实现Playground。游乐场代码表明这可以帮助解决我的问题#2“额外迭代”，但是代码实现中仍然存在一些重复，因此我仍在寻找更好的答案。
\n编辑：我也在考虑Enum 或 Trait object，无法弄清楚评估我是否需要其中之一的正确方法是什么。
\n我找到了一个令我满意的解决方案：
enum和serde(tag="...")
typejson/yaml 中的字段可能会乱序（不一定是第一个）type序列化回 json/yaml 时包含字段诀窍是使用enum_dispatch.
use serde::{Serialize, Deserialize};
use enum_dispatch::enum_dispatch;
#[derive(Debug, Clone, Serialize, Deserialize)]
struct Generator {
source_id: String,
id: String,
}
#[derive(Debug, Clone, Serialize, Deserialize)]
struct Gate {
source_id: String,
id: String,
}
#[enum_dispatch]
trait Model {fn time_advance(self, a:i32,b:i32) -> i32;}
impl Model for Generator { fn time_advance(self,a:i32,b:i32) -> i32 {a+b} }
impl Model for Gate { fn time_advance(self,a:i32,b:i32) -> i32 {a+b} }
#[enum_dispatch(Model)]
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type")]
enum ModelTypes {
Generator(Generator),
Gate(Gate),
}
fn main() {
let s = r#"
- source_id: "generator-01"
id: "connector-01"
type: "Generator"
- source_id: "geneiator-01"
type: "Gate"
id: "connector-01"
"#;
let data: Vec<ModelTypes> = serde_yaml::from_str(s).unwrap();
println!("{:?}", serde_yaml::to_string(&data));
for d in data {
println!("{:?}", d.time_advance(4, 2));
}
}
[package]
name = "enum_unpack"
version = "0.1.0"
authors = ["---"]
edition = "2018"
[dependencies]
serde = { version = "1.0.124", features = ["derive"] }
serde_yaml = "0.8.1"
enum_dispatch = "0.3.5"
输出：
[package]
name = "enum_unpack"
version = "0.1.0"
authors = ["---"]
edition = "2018"
[dependencies]
serde = { version = "1.0.124", features = ["derive"] }
serde_yaml = "0.8.1"
enum_dispatch = "0.3.5"
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