biscuit 0.8.0

A library to work with Javascript Object Signing and Encryption(JOSE), including JSON Web Tokens (JWT), JSON Web Signature (JWS) and JSON Web Encryption (JWE).
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

//! Serialize and Deserialize `num_bigint::BigUint` into `Base64urlUInt` form as described in
//! [RFC 7518](https://tools.ietf.org/html/rfc7518).
//! The integers are first converted into bytes in big-endian form and then base64 encoded.
use std::fmt;

use data_encoding::BASE64URL_NOPAD;
use num_bigint::BigUint;
use serde::de;
use serde::{Deserializer, Serializer};

/// Serialize a `BigUint` into Base64 URL encoded big endian bytes
pub fn serialize<S>(value: &Option<BigUint>, serializer: S) -> Result<S::Ok, S::Error>
where
    S: Serializer,
{
    match *value {
        Some(ref value) => {
            let bytes = value.to_bytes_be();
            let base64 = BASE64URL_NOPAD.encode(bytes.as_slice());
            serializer.serialize_some(&base64)
        }
        None => serializer.serialize_none(),
    }
}

/// Deserialize a `BigUint` from Base64 URL encoded big endian bytes
pub fn deserialize<'de, D>(deserializer: D) -> Result<Option<BigUint>, D::Error>
where
    D: Deserializer<'de>,
{
    struct BigUintVisitor;

    impl<'de> de::Visitor<'de> for BigUintVisitor {
        type Value = Option<BigUint>;

        fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
            formatter.write_str("a Base64urlUInt string")
        }

        fn visit_none<E>(self) -> Result<Self::Value, E>
        where
            E: de::Error,
        {
            Ok(None)
        }

        fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
        where
            D: Deserializer<'de>,
        {
            deserializer.deserialize_str(self)
        }

        fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
        where
            E: de::Error,
        {
            let bytes = BASE64URL_NOPAD
                .decode(value.as_bytes())
                .map_err(E::custom)?;
            Ok(Some(BigUint::from_bytes_be(&bytes)))
        }
    }

    deserializer.deserialize_option(BigUintVisitor)
}

#[cfg(test)]
mod tests {
    use num_bigint::BigUint;
    use num_traits::cast::FromPrimitive;
    use serde::{Deserialize, Serialize};

    use serde_test::{assert_tokens, Token};

    #[derive(Serialize, Deserialize, Eq, PartialEq, Debug)]
    struct TestStruct {
        #[serde(with = "super")]
        bytes: Option<BigUint>,
    }

    #[test]
    fn some_serialization_round_trip() {
        let test_value = TestStruct {
            bytes: Some(BigUint::from_u64(12345).unwrap()),
        };

        assert_tokens(
            &test_value,
            &[
                Token::Struct {
                    name: "TestStruct",
                    len: 1,
                },
                Token::Str("bytes"),
                Token::Some,
                Token::Str("MDk"),
                Token::StructEnd,
            ],
        );
    }

    #[test]
    fn none_serialization_round_trip() {
        let test_value = TestStruct { bytes: None };

        assert_tokens(
            &test_value,
            &[
                Token::Struct {
                    name: "TestStruct",
                    len: 1,
                },
                Token::Str("bytes"),
                Token::None,
                Token::StructEnd,
            ],
        );
    }

    #[test]
    fn some_json_serialization_round_trip() {
        let test_value = TestStruct {
            bytes: Some(BigUint::from_u64(12345).unwrap()),
        };
        let expected_json = r#"{"bytes":"MDk"}"#;

        let actual_json = not_err!(serde_json::to_string(&test_value));
        assert_eq!(expected_json, actual_json);

        let deserialized_value: TestStruct = not_err!(serde_json::from_str(&actual_json));
        assert_eq!(test_value, deserialized_value);
    }

    #[test]
    fn none_json_serialization_round_trip() {
        let test_value = TestStruct { bytes: None };
        let expected_json = r#"{"bytes":null}"#;

        let actual_json = not_err!(serde_json::to_string(&test_value));
        assert_eq!(expected_json, actual_json);

        let deserialized_value: TestStruct = not_err!(serde_json::from_str(&actual_json));
        assert_eq!(test_value, deserialized_value);
    }
}