反序列化未知枚举

Question

为什么这段代码不能正确反序列化消息？

收到的第一条消息预计会失败，因为数据字段 = {}，但之后数据字段与作为扁平化枚举数据一部分的贸易结构相匹配。

我做错了什么？

这是输出：

***> {"event":"bts:subscription_succeeded","channel":"live_trades_btcusd","data":{}}
===> Error("no variant of enum Data found in flattened data", line: 1, column: 79)
***> {"data":{"id":220315257,"timestamp":"1644180636","amount":0.03208,"amount_str":"0.03208000","price":41586.11,"price_str":"41586.11","type":0,"microtimestamp":"1644180636419000","buy_order_id":1455495830577152,"sell_order_id":1455495778422789},"channel":"live_trades_btcusd","event":"trade"}
===> Error("no variant of enum Data found in flattened data", line: 1, column: 290)
***> {"data":{"id":220315276,"timestamp":"1644180648","amount":0.02037389,"amount_str":"0.02037389","price":41586.11,"price_str":"41586.11","type":1,"microtimestamp":"1644180648235000","buy_order_id":1455495864238080,"sell_order_id":1455495878971395},"channel":"live_trades_btcusd","event":"trade"}

use serde::{Deserialize, Serialize};
use serde_json::json;
use tungstenite::{connect, Message};
use url::Url;

#[derive(Serialize, Deserialize, Debug)]
enum Data {
    None,
    Trade(Trade),
}

#[derive(Serialize, Deserialize, Debug)]
struct Msg {
    channel: String,
    event: String,

    #[serde(flatten)]
    data: Data,
}


#[derive(Serialize, Deserialize, Debug)]
struct Trade {
    id: u32,
    amount: f32,
    amount_str: String,
    buy_order_id: u64,
    microtimestamp: String,
    price: f32,
    price_str: String,
    sell_order_id: u64,
    timestamp: String,
    #[serde(rename = "type")]
    _type: u8,
}


        let result: Result<Msg, serde_json::Error> = serde_json::from_str(msg.to_text().unwrap());
        
        let _value = match result {
            Ok(msg) => {
                println!("---> {:?}", msg);
            }
            Err(err) => {
                println!("===> {:?}", err);
                continue;
            }
        };

https://pastebin.com/JZqPkmWC

Answer 1

我通过删除 #[serde(flatten)] 和添加 #[serde(untagged)] 解决了这个问题。感谢您的帮助！

#[derive(Serialize, Deserialize, Debug)]
#[serde(untagged)]
enum Data {
    Trade(Trade),
    Order(Order),
    None {},
}

#[derive(Serialize, Deserialize, Debug)]
struct Msg {
    channel: String,
    event: String,
    data: Data,
}

反序列化未知枚举

Deserializing an unknown enum

json

rust

enums

serde