Merge pull request #533 from nickelc/datetime-serde-micro-opt

src/datetime.rs

@@ -1195,6 +1195,10 @@ pub mod serde {
     #[derive(Debug)]
     pub struct NanoSecondsTimestampVisitor;
 
+    #[doc(hidden)]
+    #[derive(Debug)]
+    pub struct MicroSecondsTimestampVisitor;
+
     #[doc(hidden)]
     #[derive(Debug)]
     pub struct MilliSecondsTimestampVisitor;
@@ -1412,7 +1416,7 @@ pub mod serde {
         use offset::TimeZone;
         use {DateTime, Utc};
 
-        use super::serde_from;
+        use super::{serde_from, MicroSecondsTimestampVisitor};
 
         /// Serialize a UTC datetime into an integer number of microseconds since the epoch
         ///
@@ -1488,8 +1492,6 @@ pub mod serde {
             Ok(d.deserialize_i64(MicroSecondsTimestampVisitor)?)
         }
 
-        struct MicroSecondsTimestampVisitor;
-
         impl<'de> de::Visitor<'de> for MicroSecondsTimestampVisitor {
             type Value = DateTime<Utc>;
 
@@ -1524,6 +1526,162 @@ pub mod serde {
         }
     }
 
+    /// Ser/de to/from optional timestamps in microseconds
+    ///
+    /// Intended for use with `serde`'s `with` attribute.
+    ///
+    /// # Example:
+    ///
+    /// ```rust
+    /// # // We mark this ignored so that we can test on 1.13 (which does not
+    /// # // support custom derive), and run tests with --ignored on beta and
+    /// # // nightly to actually trigger these.
+    /// #
+    /// # #[macro_use] extern crate serde_derive;
+    /// # #[macro_use] extern crate serde_json;
+    /// # extern crate chrono;
+    /// # use chrono::{TimeZone, DateTime, Utc};
+    /// use chrono::serde::ts_microseconds_option;
+    /// #[derive(Deserialize, Serialize)]
+    /// struct S {
+    ///     #[serde(with = "ts_microseconds_option")]
+    ///     time: Option<DateTime<Utc>>
+    /// }
+    ///
+    /// # fn example() -> Result<S, serde_json::Error> {
+    /// let time = Some(Utc.ymd(2018, 5, 17).and_hms_micro(02, 04, 59, 918355));
+    /// let my_s = S {
+    ///     time: time.clone(),
+    /// };
+    ///
+    /// let as_string = serde_json::to_string(&my_s)?;
+    /// assert_eq!(as_string, r#"{"time":1526522699918355}"#);
+    /// let my_s: S = serde_json::from_str(&as_string)?;
+    /// assert_eq!(my_s.time, time);
+    /// # Ok(my_s)
+    /// # }
+    /// # fn main() { example().unwrap(); }
+    /// ```
+    pub mod ts_microseconds_option {
+        use core::fmt;
+        use serdelib::{de, ser};
+
+        use {DateTime, Utc};
+
+        use super::MicroSecondsTimestampVisitor;
+
+        /// Serialize a UTC datetime into an integer number of microseconds since the epoch or none
+        ///
+        /// Intended for use with `serde`s `serialize_with` attribute.
+        ///
+        /// # Example:
+        ///
+        /// ```rust
+        /// # // We mark this ignored so that we can test on 1.13 (which does not
+        /// # // support custom derive), and run tests with --ignored on beta and
+        /// # // nightly to actually trigger these.
+        /// #
+        /// # #[macro_use] extern crate serde_derive;
+        /// # #[macro_use] extern crate serde_json;
+        /// # extern crate chrono;
+        /// # use chrono::{TimeZone, DateTime, Utc};
+        /// use chrono::serde::ts_microseconds_option::serialize as to_micro_tsopt;
+        /// #[derive(Serialize)]
+        /// struct S {
+        ///     #[serde(serialize_with = "to_micro_tsopt")]
+        ///     time: Option<DateTime<Utc>>
+        /// }
+        ///
+        /// # fn example() -> Result<String, serde_json::Error> {
+        /// let my_s = S {
+        ///     time: Some(Utc.ymd(2018, 5, 17).and_hms_micro(02, 04, 59, 918355)),
+        /// };
+        /// let as_string = serde_json::to_string(&my_s)?;
+        /// assert_eq!(as_string, r#"{"time":1526522699918355}"#);
+        /// # Ok(as_string)
+        /// # }
+        /// # fn main() { example().unwrap(); }
+        /// ```
+        pub fn serialize<S>(opt: &Option<DateTime<Utc>>, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: ser::Serializer,
+        {
+            match *opt {
+                Some(ref dt) => serializer.serialize_some(&dt.timestamp_micros()),
+                None => serializer.serialize_none(),
+            }
+        }
+
+        /// Deserialize a `DateTime` from a microsecond timestamp or none
+        ///
+        /// Intended for use with `serde`s `deserialize_with` attribute.
+        ///
+        /// # Example:
+        ///
+        /// ```rust
+        /// # // We mark this ignored so that we can test on 1.13 (which does not
+        /// # // support custom derive), and run tests with --ignored on beta and
+        /// # // nightly to actually trigger these.
+        /// #
+        /// # #[macro_use] extern crate serde_derive;
+        /// # #[macro_use] extern crate serde_json;
+        /// # extern crate chrono;
+        /// # use chrono::{DateTime, Utc};
+        /// use chrono::serde::ts_microseconds_option::deserialize as from_micro_tsopt;
+        /// #[derive(Deserialize)]
+        /// struct S {
+        ///     #[serde(deserialize_with = "from_micro_tsopt")]
+        ///     time: Option<DateTime<Utc>>
+        /// }
+        ///
+        /// # fn example() -> Result<S, serde_json::Error> {
+        /// let my_s: S = serde_json::from_str(r#"{ "time": 1526522699918355 }"#)?;
+        /// # Ok(my_s)
+        /// # }
+        /// # fn main() { example().unwrap(); }
+        /// ```
+        pub fn deserialize<'de, D>(d: D) -> Result<Option<DateTime<Utc>>, D::Error>
+        where
+            D: de::Deserializer<'de>,
+        {
+            Ok(d.deserialize_option(OptionMicroSecondsTimestampVisitor)?)
+        }
+
+        struct OptionMicroSecondsTimestampVisitor;
+
+        impl<'de> de::Visitor<'de> for OptionMicroSecondsTimestampVisitor {
+            type Value = Option<DateTime<Utc>>;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                write!(formatter, "a unix timestamp in microseconds or none")
+            }
+
+            /// Deserialize a timestamp in seconds since the epoch
+            fn visit_some<D>(self, d: D) -> Result<Option<DateTime<Utc>>, D::Error>
+            where
+                D: de::Deserializer<'de>,
+            {
+                d.deserialize_i64(MicroSecondsTimestampVisitor).map(Some)
+            }
+
+            /// Deserialize a timestamp in seconds since the epoch
+            fn visit_none<E>(self) -> Result<Option<DateTime<Utc>>, E>
+            where
+                E: de::Error,
+            {
+                Ok(None)
+            }
+
+            /// Deserialize a timestamp in seconds since the epoch
+            fn visit_unit<E>(self) -> Result<Option<DateTime<Utc>>, E>
+            where
+                E: de::Error,
+            {
+                Ok(None)
+            }
+        }
+    }
+
     /// Ser/de to/from timestamps in nanoseconds
     ///
     /// Intended for use with `serde`'s `with` attribute.