1 use serde::{Deserialize, Deserializer};
2 use std::convert::TryFrom;
3 use std::fmt::{self, Display};
4 use std::marker::PhantomData;
5 use std::str::FromStr;
6
7 pub struct NumberVisitor<T> {
8 marker: PhantomData<T>,
9 }
10
11 impl<'de, T> serde::de::Visitor<'de> for NumberVisitor<T>
12 where
13 T: TryFrom<u64> + TryFrom<i64> + FromStr,
14 <T as TryFrom<u64>>::Error: Display,
15 <T as TryFrom<i64>>::Error: Display,
16 <T as FromStr>::Err: Display,
17 {
18 type Value = T;
19
expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result20 fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
21 formatter.write_str("an integer or string")
22 }
23
visit_u64<E>(self, v: u64) -> Result<Self::Value, E> where E: serde::de::Error,24 fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E>
25 where
26 E: serde::de::Error,
27 {
28 T::try_from(v).map_err(serde::de::Error::custom)
29 }
30
visit_i64<E>(self, v: i64) -> Result<Self::Value, E> where E: serde::de::Error,31 fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E>
32 where
33 E: serde::de::Error,
34 {
35 T::try_from(v).map_err(serde::de::Error::custom)
36 }
37
visit_str<E>(self, v: &str) -> Result<Self::Value, E> where E: serde::de::Error,38 fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
39 where
40 E: serde::de::Error,
41 {
42 v.parse().map_err(serde::de::Error::custom)
43 }
44 }
45
deserialize_integer_or_string<'de, D, T>(deserializer: D) -> Result<T, D::Error> where D: Deserializer<'de>, T: TryFrom<u64> + TryFrom<i64> + FromStr, <T as TryFrom<u64>>::Error: Display, <T as TryFrom<i64>>::Error: Display, <T as FromStr>::Err: Display,46 fn deserialize_integer_or_string<'de, D, T>(deserializer: D) -> Result<T, D::Error>
47 where
48 D: Deserializer<'de>,
49 T: TryFrom<u64> + TryFrom<i64> + FromStr,
50 <T as TryFrom<u64>>::Error: Display,
51 <T as TryFrom<i64>>::Error: Display,
52 <T as FromStr>::Err: Display,
53 {
54 deserializer.deserialize_any(NumberVisitor {
55 marker: PhantomData,
56 })
57 }
58
59 #[derive(Deserialize, Debug)]
60 pub struct Struct {
61 #[serde(deserialize_with = "deserialize_integer_or_string")]
62 pub i: i64,
63 }
64
65 #[test]
test()66 fn test() {
67 let j = r#" {"i":100} "#;
68 println!("{:?}", serde_json::from_str::<Struct>(j).unwrap());
69
70 let j = r#" {"i":"100"} "#;
71 println!("{:?}", serde_json::from_str::<Struct>(j).unwrap());
72 }
73