1 #![allow(clippy::trait_duplication_in_bounds)] // https://github.com/rust-lang/rust-clippy/issues/8757
2
3 use serde::{Deserialize, Deserializer};
4 use std::convert::TryFrom;
5 use std::fmt::{self, Display};
6 use std::marker::PhantomData;
7 use std::str::FromStr;
8
9 pub struct NumberVisitor<T> {
10 marker: PhantomData<T>,
11 }
12
13 impl<'de, T> serde::de::Visitor<'de> for NumberVisitor<T>
14 where
15 T: TryFrom<u64> + TryFrom<i64> + FromStr,
16 <T as TryFrom<u64>>::Error: Display,
17 <T as TryFrom<i64>>::Error: Display,
18 <T as FromStr>::Err: Display,
19 {
20 type Value = T;
21
expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result22 fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
23 formatter.write_str("an integer or string")
24 }
25
visit_u64<E>(self, v: u64) -> Result<Self::Value, E> where E: serde::de::Error,26 fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E>
27 where
28 E: serde::de::Error,
29 {
30 T::try_from(v).map_err(serde::de::Error::custom)
31 }
32
visit_i64<E>(self, v: i64) -> Result<Self::Value, E> where E: serde::de::Error,33 fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E>
34 where
35 E: serde::de::Error,
36 {
37 T::try_from(v).map_err(serde::de::Error::custom)
38 }
39
visit_str<E>(self, v: &str) -> Result<Self::Value, E> where E: serde::de::Error,40 fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
41 where
42 E: serde::de::Error,
43 {
44 v.parse().map_err(serde::de::Error::custom)
45 }
46 }
47
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,48 fn deserialize_integer_or_string<'de, D, T>(deserializer: D) -> Result<T, D::Error>
49 where
50 D: Deserializer<'de>,
51 T: TryFrom<u64> + TryFrom<i64> + FromStr,
52 <T as TryFrom<u64>>::Error: Display,
53 <T as TryFrom<i64>>::Error: Display,
54 <T as FromStr>::Err: Display,
55 {
56 deserializer.deserialize_any(NumberVisitor {
57 marker: PhantomData,
58 })
59 }
60
61 #[derive(Deserialize, Debug)]
62 pub struct Struct {
63 #[serde(deserialize_with = "deserialize_integer_or_string")]
64 pub i: i64,
65 }
66
67 #[test]
test()68 fn test() {
69 let j = r#" {"i":100} "#;
70 println!("{:?}", serde_json::from_str::<Struct>(j).unwrap());
71
72 let j = r#" {"i":"100"} "#;
73 println!("{:?}", serde_json::from_str::<Struct>(j).unwrap());
74 }
75