使用serde序列化结构时如何展平`Vec`字段? [英] How to flatten a `Vec` field when serializing a struct with serde?

问题描述

我有一些 XML 的标签包含多个同名的兄弟标签，如下所示:

I've got some XML that has a tag containing multiple sibling tags with the same name, like so:

<foo>
    <bar/>
    <bar/>
</foo>

(也可能有多个顶级 <foo> ，尽管我还没有尝试对其进行(反)序列化.)

(There may also be multiple top level <foo>s as well, though I've not gotten around to trying to (de)serialize that yet.)

使用此代码:

use serde::{Deserialize, Serialize};
use quick_xml::de::from_str;
use quick_xml::se::to_string;

#[derive(Debug, Deserialize, PartialEq, Serialize)]
pub struct Foo {
    #[serde(rename = "bar", default)]
    bars: Vec<Bar>,
}

#[derive(Debug, Deserialize, PartialEq, Serialize)]
#[serde(rename = "bar")]
struct Bar{

}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn deserialize_trivial_string_test() {
        let fs = "<foo><bar/><bar/></foo>";
        let foo = from_str(fs).unwrap();
        assert_eq!(Foo { bars: vec![Bar {}, Bar {}] }, foo);
    }

    #[test]
    fn serialize_trivial_string_test() {
        let foo = Foo { bars: vec![Bar {}, Bar {}] };
        let fs = to_string(&foo).unwrap();
        assert_eq!("<foo><bar/><bar/></foo>", fs);
    }
}

不要忘记激活序列化功能:

and don't forget to activate serialize feature:

[dependencies.quick-xml]
version = "0.18.1"
features = ["serialize"]

我可以很好地反序列化，但是序列化添加了一个额外的 标记作为 bars 字段包装实际的 代码>标签:

I can deserialize just fine, but serialization adds in an extra <bar> tag as the bars field wrapping the actual <bar> tags:

<Foo>
    <bar>
        <bar></bar>
        <bar></bar>
    </bar>
</Foo>

bars 字段上的 #[serde(rename = "bar", default)] 是我第一次尝试解决这个问题，基于 quick-xml 的文档，但它显然不起作用.我还查看了 serde 的文档，确实找到了 flatten 属性，但是当我尝试将其应用于 bars 字段时，它似乎不起作用.

The #[serde(rename = "bar", default)] on the bars field was my first attempt to fix the this, based on quick-xml's documentation, but it obviously does not work. I also looked through serde's documentation, and did find a flatten attribute, but it did not seem to work when I tried applying it to the bars field.

除了手动实现Deserialize之外，有什么方法可以获得我需要的序列化吗?

Is there any way to get the serialization that I need, short of manually implementing Deserialize?

如果相关，我尝试使用的实际数据格式是 flam3 文件格式.这里有一个示例文件.<flame> 元素在这里等同于 ，而 等同于 <;bar>.

In case it's relevant, the actual data format I'm trying to work with is the flam3 file format. There's a sample file here. The <flame> element would be the equivalent to <foo> here, and <xform> is equivalent to <bar>.

推荐答案

很遗憾，您不能.GitHub 上有一个未决问题可以解决您的问题.

Unfortunately you can't. There is a outstanding issue on GitHub that addresses your question.

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