allow downloading individual files from bundle

src/timestamp.rs

@@ -0,0 +1,38 @@
+use core::fmt;
+
+use serde::{de::Visitor, Deserializer, Serializer};
+use time::OffsetDateTime;
+
+pub(crate) fn serialize<S: Serializer>(
+    time: &OffsetDateTime,
+    ser: S,
+) -> Result<S::Ok, S::Error> {
+    ser.serialize_i64(time.unix_timestamp())
+}
+
+struct I64Visitor;
+
+impl<'de> Visitor<'de> for I64Visitor {
+    type Value = i64;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        write!(formatter, "an integer")
+    }
+
+    fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E> {
+        Ok(v)
+    }
+
+    fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E> {
+        Ok(v as i64)
+    }
+}
+
+pub(crate) fn deserialize<'de, D: Deserializer<'de>>(
+    de: D,
+) -> Result<OffsetDateTime, D::Error> {
+    Ok(
+        OffsetDateTime::from_unix_timestamp(de.deserialize_i64(I64Visitor)?)
+            .unwrap_or_else(|_| OffsetDateTime::now_utc()),
+    )
+}