Struct DateTime

pub struct DateTime(/* private fields */);

Struct representing a BSON datetime. Note: BSON datetimes have millisecond precision.

To enable conversions between this type and [chrono::DateTime], enable the "chrono-0_4" feature flag in your Cargo.toml.

use chrono::prelude::*;
let chrono_dt: chrono::DateTime<Utc> = "2014-11-28T12:00:09Z".parse()?;
let bson_dt: bson::DateTime = chrono_dt.into();
let bson_dt = bson::DateTime::from_chrono(chrono_dt);
let back_to_chrono: chrono::DateTime<Utc> = bson_dt.into();
let back_to_chrono = bson_dt.to_chrono();

You may also construct this type from a given year, month, day, and optionally, an hour, minute, second and millisecond, which default to 0 if not explicitly set.

let dt = bson::DateTime::builder().year(1998).month(2).day(12).minute(1).millisecond(23).build()?;
let expected = bson::DateTime::parse_rfc3339_str("1998-02-12T00:01:00.023Z")?;
assert_eq!(dt, expected);

Serde integration

This type differs from [chrono::DateTime] in that it serializes to and deserializes from a BSON datetime rather than an RFC 3339 formatted string.

e.g.

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
struct Foo {
    // serializes as a BSON datetime.
    date_time: bson::DateTime,

    // serializes as an RFC 3339 / ISO-8601 string.
    chrono_datetime: chrono::DateTime<chrono::Utc>,
}

let f = Foo { date_time: bson::DateTime::now(), chrono_datetime: chrono::Utc::now() };
println!("{:?}", bson::to_document(&f)?);

Produces the following output:

{ "date_time": DateTime("2023-01-23 20:11:47.316 +00:00:00"), "chrono_datetime": "2023-01-23T20:11:47.316114543Z" }

Additionally, in non-BSON formats, it will serialize to and deserialize from that format’s equivalent of the extended JSON representation of a datetime.

e.g.

let f = Foo { date_time: bson::DateTime::now(), chrono_datetime: chrono::Utc::now() };
println!("{}", serde_json::to_string(&f)?);

Produces the following output:

{"date_time":{"$date":{"$numberLong":"1674504029491"}},"chrono_datetime":"2023-01-23T20:00:29.491791120Z"}

serde_helpers

The bson crate provides a number of useful helpers for serializing and deserializing various datetime types to and from different formats. For example, to serialize a [chrono::DateTime] as a BSON datetime, you can use [crate::serde_helpers::chrono_datetime_as_bson_datetime]. Similarly, to serialize a BSON DateTime to a string, you can use crate::serde_helpers::bson_datetime_as_rfc3339_string. Check out the crate::serde_helpers module documentation for a list of all of the helpers offered by the crate.

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
struct Foo {
    // serializes as a BSON datetime.
    date_time: bson::DateTime,

    // serializes as an RFC 3339 / ISO-8601 string.
    chrono_datetime: chrono::DateTime<chrono::Utc>,

    // serializes as a BSON datetime.
    // this requires the "chrono-0_4" feature flag
    #[serde(with = "bson::serde_helpers::chrono_datetime_as_bson_datetime")]
    chrono_as_bson: chrono::DateTime<chrono::Utc>,

    // serializes as an RFC 3339 / ISO-8601 string.
    #[serde(with = "bson::serde_helpers::bson_datetime_as_rfc3339_string")]
    bson_as_string: bson::DateTime,
}

The serde_with-3 feature flag

The serde_with-3 feature can be enabled to support more ergonomic serde attributes for (de)serializing [chrono::DateTime] from/to BSON via the serde_with crate. The main benefit of this compared to the regular serde_helpers is that serde_with-3 can handle nested [chrono::DateTime] values (e.g. in Option), whereas the former only works on fields that are exactly [chrono::DateTime].

use serde::{Deserialize, Serialize};
use bson::doc;

#[serde_with_3::serde_as]
#[derive(Deserialize, Serialize, PartialEq, Debug)]
struct Foo {
  /// Serializes as a BSON datetime rather than using [`chrono::DateTime`]'s serialization
  #[serde_as(as = "Option<bson::DateTime>")]
  as_bson: Option<chrono::DateTime<chrono::Utc>>,
}

let dt = chrono::Utc::now();
let foo = Foo {
  as_bson: Some(dt),
};

let expected = doc! {
  "as_bson": bson::DateTime::from_chrono(dt),
};

assert_eq!(bson::to_document(&foo)?, expected);

Implementations

impl DateTime

pub const MAX: DateTime

The latest possible date that can be represented in BSON.

pub const MIN: DateTime

The earliest possible date that can be represented in BSON.

pub const fn from_millis(date: i64) -> DateTime

Makes a new DateTime from the number of non-leap milliseconds since January 1, 1970 0:00:00 UTC (aka “UNIX timestamp”).

pub fn now() -> DateTime

Returns a DateTime which corresponds to the current date and time.

pub fn builder() -> DateTimeBuilder

Returns a builder used to construct a DateTime from a given year, month, day, and optionally, an hour, minute, second and millisecond, which default to 0 if not explicitly set.

Note: You cannot call build() before setting at least the year, month and day.

pub fn from_system_time(st: SystemTime) -> DateTime

Convert the given std::time::SystemTime to a DateTime.

If the provided time is too far in the future or too far in the past to be represented by a BSON datetime, either DateTime::MAX or DateTime::MIN will be returned, whichever is closer.

pub fn to_system_time(self) -> SystemTime

Convert this DateTime to a std::time::SystemTime.

pub const fn timestamp_millis(self) -> i64

Returns the number of non-leap-milliseconds since January 1, 1970 UTC.

pub const fn saturating_add_millis(self, millis: i64) -> DateTime

Adds millis milliseconds to the DateTime saturating at DateTime::MIN and DateTime::MAX.

pub const fn saturating_add_duration(self, duration: Duration) -> DateTime

Adds duration to the DateTime saturating at DateTime::MAX.

As DateTime only have millisecond-precision this will only use the whole milliseconds of duration.

pub fn to_rfc3339_string(self) -> String

👎Deprecated since 2.3.0: Use try_to_rfc3339_string instead.

Convert this DateTime to an RFC 3339 formatted string. Panics if it could not be represented in that format.

pub fn try_to_rfc3339_string(self) -> Result<String, Error>

Convert this DateTime to an RFC 3339 formatted string.

pub fn parse_rfc3339_str(s: impl AsRef<str>) -> Result<DateTime, Error>

Convert the given RFC 3339 formatted string to a DateTime, truncating it to millisecond precision.

pub fn checked_duration_since(self, earlier: DateTime) -> Option<Duration>

Returns the time elapsed since earlier, or None if the given DateTime is later than this one.

pub fn saturating_duration_since(self, earlier: DateTime) -> Duration

Returns the time elapsed since earlier, or a Duration of zero if the given DateTime is later than this one.

Trait Implementations

impl Clone for DateTime

fn clone(&self) -> DateTime

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DateTime

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for DateTime

fn deserialize<D>( deserializer: D, ) -> Result<DateTime, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for DateTime

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

Formats the value using the given formatter.

impl From<DateTime> for Bson

fn from(dt: DateTime) -> Bson

Converts to this type from the input type.

impl From<DateTime> for RawBson

fn from(dt: DateTime) -> RawBson

Converts to this type from the input type.

impl From<DateTime> for RawBsonRef<'_>

fn from(dt: DateTime) -> RawBsonRef<'_>

Converts to this type from the input type.

impl From<SystemTime> for DateTime

fn from(st: SystemTime) -> DateTime

Converts to this type from the input type.

impl Hash for DateTime

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for DateTime

fn cmp(&self, other: &DateTime) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for DateTime

fn eq(&self, other: &DateTime) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for DateTime

fn partial_cmp(&self, other: &DateTime) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for DateTime

fn serialize<S>( &self, serializer: S, ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for DateTime

impl Eq for DateTime

impl StructuralPartialEq for DateTime