Struct serde_with::TimestampSecondsWithFrac

pub struct TimestampSecondsWithFrac<FORMAT: Format = f64, STRICTNESS: Strictness = Strict>(_);

De/Serialize timestamps as seconds since the UNIX epoch

De/serialize timestamps as seconds since the UNIX epoch. Subsecond precision is only supported for TimestampSecondsWithFrac, but not for TimestampSeconds. You can configure the serialization format between integers, floats, and stringified numbers with the FORMAT specifier and configure the deserialization with the STRICTNESS specifier.

The STRICTNESS specifier can either be formats::Strict or formats::Flexible and defaults to formats::Strict. formats::Strict means that deserialization only supports the type given in FORMAT, e.g., if FORMAT is i64 deserialization from a f64 will error. formats::Flexible means that deserialization will perform a best effort to extract the correct timestamp and allows deserialization from any type. For example, deserializing TimestampSeconds<f64, Flexible> will discard any subsecond precision during deserialization from f64 and will parse a String as an integer number.

This type also supports chrono::DateTime with the chrono-feature flag.

Timestamp Type	Converter	Available FORMATs
std::time::SystemTime	TimestampSeconds	i64, f64, String
std::time::SystemTime	TimestampSecondsWithFrac	f64, String
chrono::DateTime<Utc>	TimestampSeconds	i64, f64, String
chrono::DateTime<Utc>	TimestampSecondsWithFrac	f64, String
chrono::DateTime<Local>	TimestampSeconds	i64, f64, String
chrono::DateTime<Local>	TimestampSecondsWithFrac	f64, String

Examples

use std::time::{Duration, SystemTime};

#[serde_as]
#[derive(Deserialize, Serialize)]
struct Timestamps {
    #[serde_as(as = "TimestampSecondsWithFrac<f64>")]
    st_f64: SystemTime,
    #[serde_as(as = "TimestampSecondsWithFrac<String>")]
    st_string: SystemTime,
};

// Serialization
// See how the values get rounded, since subsecond precision is not allowed.

let ts = Timestamps {
    st_f64: SystemTime::UNIX_EPOCH.checked_add(Duration::new(12345, 500_000_000)).unwrap(),
    st_string: SystemTime::UNIX_EPOCH.checked_add(Duration::new(12345, 999_999_000)).unwrap(),
};
// Observe the different datatypes
let expected = json!({
    "st_f64": 12345.5,
    "st_string": "12345.999999",
});
assert_eq!(expected, serde_json::to_value(&ts).unwrap());

// Deserialization works too
// Subsecond precision in numbers will be rounded away

let json = json!({
    "st_f64": 12345.5,
    "st_string": "12345.987654",
});
let expected = Timestamps {
    st_f64: SystemTime::UNIX_EPOCH.checked_add(Duration::new(12345, 500_000_000)).unwrap(),
    st_string: SystemTime::UNIX_EPOCH.checked_add(Duration::new(12345, 987_654_000)).unwrap(),
};
assert_eq!(expected, serde_json::from_value(json).unwrap());

chrono::DateTime<Utc> and chrono::DateTime<Local> are also supported when using the chrono feature. Like SystemTime, it is a signed timestamp, thus can be de/serialized as an i64.

use chrono::{DateTime, Local, TimeZone, Utc};

#[serde_as]
#[derive(Deserialize, Serialize)]
struct Timestamps {
    #[serde_as(as = "TimestampSecondsWithFrac<f64>")]
    dt_f64: DateTime<Utc>,
    #[serde_as(as = "TimestampSecondsWithFrac<String>")]
    dt_string: DateTime<Local>,
};

// Serialization

let ts = Timestamps {
    dt_f64: Utc.timestamp(-12345, 500_000_000),
    dt_string: Local.timestamp(12345, 999_999_000),
};
// Observe the different datatypes
let expected = json!({
    "dt_f64": -12344.5,
    "dt_string": "12345.999999",
});
assert_eq!(expected, serde_json::to_value(&ts).unwrap());

// Deserialization works too

let json = json!({
    "dt_f64": -12344.5,
    "dt_string": "12345.987",
});
let expected = Timestamps {
    dt_f64: Utc.timestamp(-12345, 500_000_000),
    dt_string: Local.timestamp(12345, 987_000_000),
};
assert_eq!(expected, serde_json::from_value(json).unwrap());

Trait Implementations

impl<FORMAT: Clone + Format, STRICTNESS: Clone + Strictness> Clone for TimestampSecondsWithFrac<FORMAT, STRICTNESS>

fn clone(&self) -> TimestampSecondsWithFrac<FORMAT, STRICTNESS>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<FORMAT: Debug + Format, STRICTNESS: Debug + Strictness> Debug for TimestampSecondsWithFrac<FORMAT, STRICTNESS>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<FORMAT: Default + Format, STRICTNESS: Default + Strictness> Default for TimestampSecondsWithFrac<FORMAT, STRICTNESS>

fn default() -> TimestampSecondsWithFrac<FORMAT, STRICTNESS>

Returns the “default value” for a type.

impl<'de> DeserializeAs<'de, SystemTime> for TimestampSecondsWithFrac<f64, Strict>

fn deserialize_as<D>(deserializer: D) -> Result<SystemTime, D::Error> where
    D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl<'de> DeserializeAs<'de, SystemTime> for TimestampSecondsWithFrac<String, Strict>

fn deserialize_as<D>(deserializer: D) -> Result<SystemTime, D::Error> where
    D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl<'de, FORMAT> DeserializeAs<'de, SystemTime> for TimestampSecondsWithFrac<FORMAT, Flexible> where
    FORMAT: Format, 

fn deserialize_as<D>(deserializer: D) -> Result<SystemTime, D::Error> where
    D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl<STRICTNESS> SerializeAs<SystemTime> for TimestampSecondsWithFrac<f64, STRICTNESS> where
    STRICTNESS: Strictness, 

fn serialize_as<S>(
    source: &SystemTime,
    serializer: S
) -> Result<S::Ok, S::Error> where
    S: Serializer, 

Serialize this value into the given Serde serializer.

impl<STRICTNESS> SerializeAs<SystemTime> for TimestampSecondsWithFrac<String, STRICTNESS> where
    STRICTNESS: Strictness, 

fn serialize_as<S>(
    source: &SystemTime,
    serializer: S
) -> Result<S::Ok, S::Error> where
    S: Serializer, 

Serialize this value into the given Serde serializer.

impl<FORMAT: Copy + Format, STRICTNESS: Copy + Strictness> Copy for TimestampSecondsWithFrac<FORMAT, STRICTNESS>