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
147
148
149
150
151
152
153
154
155
156
157
158
159

//! Serialize/deserialize Timestamp type from and into string:
use serde::{de::Error as _, Deserialize, Deserializer, Serialize, Serializer};

use crate::google::protobuf::Timestamp;
use chrono::{DateTime, LocalResult, TimeZone, Utc};
use serde::ser::Error;

/// Helper struct to serialize and deserialize Timestamp into an RFC3339-compatible string
/// This is required because the serde `with` attribute is only available to fields of a struct but
/// not the whole struct.
#[derive(Debug, Serialize, Deserialize)]
#[serde(transparent)]
pub struct Rfc3339(#[serde(with = "crate::serializers::timestamp")] Timestamp);

impl From<Timestamp> for Rfc3339 {
    fn from(value: Timestamp) -> Self {
        Rfc3339(value)
    }
}
impl From<Rfc3339> for Timestamp {
    fn from(value: Rfc3339) -> Self {
        value.0
    }
}

/// Deserialize string into Timestamp
pub fn deserialize<'de, D>(deserializer: D) -> Result<Timestamp, D::Error>
where
    D: Deserializer<'de>,
{
    let value_string = String::deserialize(deserializer)?;
    let value_datetime = DateTime::parse_from_rfc3339(value_string.as_str())
        .map_err(|e| D::Error::custom(format!("{}", e)))?;
    Ok(Timestamp {
        seconds: value_datetime.timestamp(),
        nanos: value_datetime.timestamp_subsec_nanos() as i32,
    })
}

/// Serialize from Timestamp into string
pub fn serialize<S>(value: &Timestamp, serializer: S) -> Result<S::Ok, S::Error>
where
    S: Serializer,
{
    if value.nanos < 0 {
        return Err(S::Error::custom("invalid nanoseconds in time"));
    }
    match Utc.timestamp_opt(value.seconds, value.nanos as u32) {
        LocalResult::None => Err(S::Error::custom("invalid time")),
        LocalResult::Single(t) => Ok(as_rfc3339_nanos(&t)),
        LocalResult::Ambiguous(_, _) => Err(S::Error::custom("ambiguous time")),
    }?
    .serialize(serializer)
}

/// Serialization helper for converting a `DateTime<Utc>` object to a string.
///
/// This reproduces the behavior of Go's `time.RFC3339Nano` format,
/// ie. a RFC3339 date-time with left-padded subsecond digits without
///     trailing zeros and no trailing dot.
pub fn as_rfc3339_nanos(t: &DateTime<Utc>) -> String {
    use chrono::format::{Fixed, Item, Numeric::*, Pad::Zero};

    const PREFIX: &[Item<'_>] = &[
        Item::Numeric(Year, Zero),
        Item::Literal("-"),
        Item::Numeric(Month, Zero),
        Item::Literal("-"),
        Item::Numeric(Day, Zero),
        Item::Literal("T"),
        Item::Numeric(Hour, Zero),
        Item::Literal(":"),
        Item::Numeric(Minute, Zero),
        Item::Literal(":"),
        Item::Numeric(Second, Zero),
    ];

    const NANOS: &[Item<'_>] = &[Item::Fixed(Fixed::Nanosecond)];

    // Format as RFC339 without nanoseconds nor timezone marker
    let prefix = t.format_with_items(PREFIX.iter());

    // Format nanoseconds with dot, leading zeros, and variable number of trailing zeros
    let nanos = t.format_with_items(NANOS.iter()).to_string();

    // Trim trailing zeros and remove leftover dot if any
    let nanos_trimmed = nanos.trim_end_matches('0').trim_end_matches('.');

    format!("{}{}Z", prefix, nanos_trimmed)
}

#[allow(warnings)]
#[cfg(test)]
mod test {
    use super::*;
    use crate::google::protobuf::Timestamp;
    use serde::{Deserialize, Serialize};

    // The Go code with which the following timestamps
    // were tested is as follows:
    //
    // ```go
    // package main
    //
    // import (
    //     "fmt"
    //     "time"
    // )
    //
    // func main() {
    //     timestamps := []string{
    //         "1970-01-01T00:00:00Z",
    //         "0001-01-01T00:00:00Z",
    //         "2020-09-14T16:33:00Z",
    //         "2020-09-14T16:33:00.1Z",
    //         "2020-09-14T16:33:00.211914212Z",
    //         "2020-09-14T16:33:54.21191421Z",
    //         "2021-01-07T20:25:56.045576Z",
    //         "2021-01-07T20:25:57.039219Z",
    //         "2021-01-07T20:26:05.00509Z",
    //         "2021-01-07T20:26:05.005096Z",
    //         "2021-01-07T20:26:05.0005096Z",
    //     }
    //     for _, timestamp := range timestamps {
    //         ts, err := time.Parse(time.RFC3339Nano, timestamp)
    //         if err != nil {
    //             panic(err)
    //         }
    //         tss := ts.Format(time.RFC3339Nano)
    //         if timestamp != tss {
    //             panic(fmt.Sprintf("\nExpected : %s\nActual   : %s", timestamp, tss))
    //         }
    //     }
    //     fmt.Println("All good!")
    // }
    // ```
    #[test]
    fn json_timestamp_precision() {
        let test_timestamps = vec![
            "1970-01-01T00:00:00Z",
            "0001-01-01T00:00:00Z",
            "2020-09-14T16:33:00Z",
            "2020-09-14T16:33:00.1Z",
            "2020-09-14T16:33:00.211914212Z",
            "2020-09-14T16:33:54.21191421Z",
            "2021-01-07T20:25:56.045576Z",
            "2021-01-07T20:25:57.039219Z",
            "2021-01-07T20:26:05.00509Z",
            "2021-01-07T20:26:05.005096Z",
            "2021-01-07T20:26:05.0005096Z",
        ];

        for timestamp in test_timestamps {
            let json = format!("\"{}\"", timestamp);
            let rfc = serde_json::from_str::<Rfc3339>(&json).unwrap();
            assert_eq!(json, serde_json::to_string(&rfc).unwrap());
        }
    }
}