Add support for RFC 2822 in DateTime

crates/lune-std-datetime/src/date_time.rs

@@ -173,6 +173,21 @@ impl DateTime {
         Ok(Self { inner })
     }
 
+    /**
+        Parses a time string in the RFC 2822 format, such as
+        `Tue, 1 Jul 2003 10:52:37 +0200`, into a new `DateTime` struct.
+
+        See [`chrono::DateTime::parse_from_rfc2822`] for additional details.
+
+        # Errors
+
+        Returns an error if the input string is not a valid RFC 2822 date-time.
+    */
+    pub fn from_rfc_date(rfc_date: impl AsRef<str>) -> DateTimeResult<Self> {
+        let inner = ChronoDateTime::parse_from_rfc2822(rfc_date.as_ref())?.with_timezone(&Utc);
+        Ok(Self { inner })
+    }
+
     /**
         Extracts individual date & time values from this
         `DateTime`, using the current local time zone.
@@ -200,6 +215,16 @@ impl DateTime {
     pub fn to_iso_date(self) -> String {
         self.inner.to_rfc3339()
     }
+
+    /**
+        Formats a time string in the RFC 2822 format, such as `Tue, 1 Jul 2003 10:52:37 +0200`.
+
+        See [`chrono::DateTime::to_rfc2822`] for additional details.
+    */
+    #[must_use]
+    pub fn to_rfc_date(self) -> String {
+        self.inner.to_rfc2822()
+    }
 }
 
 impl LuaUserData for DateTime {
@@ -230,6 +255,7 @@ impl LuaUserData for DateTime {
         );
         // Normal methods
         methods.add_method("toIsoDate", |_, this, ()| Ok(this.to_iso_date()));
+        methods.add_method("toRfcDate", |_, this, ()| Ok(this.to_rfc_date()));
         methods.add_method(
             "formatUniversalTime",
             |_, this, (format, locale): (Option<String>, Option<String>)| {

crates/lune-std-datetime/src/lib.rs

@@ -22,6 +22,9 @@ pub fn module(lua: &Lua) -> LuaResult<LuaTable> {
         .with_function("fromIsoDate", |_, iso_date: String| {
             Ok(DateTime::from_iso_date(iso_date)?)
         })?
+        .with_function("fromRfcDate", |_, rfc_date: String| {
+            Ok(DateTime::from_rfc_date(rfc_date)?)
+        })?
         .with_function("fromLocalTime", |_, values| {
             Ok(DateTime::from_local_time(&values)?)
         })?

crates/lune/src/tests.rs

@@ -90,11 +90,13 @@ create_tests! {
     datetime_format_local_time: "datetime/formatLocalTime",
     datetime_format_universal_time: "datetime/formatUniversalTime",
     datetime_from_iso_date: "datetime/fromIsoDate",
+    datetime_from_rfc_date: "datetime/fromRfcDate",
     datetime_from_local_time: "datetime/fromLocalTime",
     datetime_from_universal_time: "datetime/fromUniversalTime",
     datetime_from_unix_timestamp: "datetime/fromUnixTimestamp",
     datetime_now: "datetime/now",
     datetime_to_iso_date: "datetime/toIsoDate",
+    datetime_to_rfc_date: "datetime/toRfcDate",
     datetime_to_local_time: "datetime/toLocalTime",
     datetime_to_universal_time: "datetime/toUniversalTime",
 }

tests/datetime/fromRfcDate.luau

@@ -0,0 +1,11 @@
+local DateTime = require("@lune/datetime")
+
+assert(
+	DateTime.fromRfcDate("Fri, 21 Nov 1997 09:55:06 -0600") ~= nil,
+	"expected DateTime.fromRfcDate() to return DateTime, got nil"
+)
+
+assert(
+	DateTime.fromRfcDate("Tue, 1 Jul 2003 10:52:37 +0200") ~= nil,
+	"expected DateTime.fromRfcDate() to return DateTime, got nil"
+)

tests/datetime/toRfcDate.luau

@@ -0,0 +1,51 @@
+local DateTime = require("@lune/datetime")
+
+local now = DateTime.now()
+local nowRfc = now:toRfcDate()
+
+assert(type(nowRfc) == "string", "toRfcDate should return a string")
+assert(
+	string.match(nowRfc, "^%a%a%a, %d%d? %a%a%a %d%d%d%d %d%d:%d%d:%d%d [+-]%d%d%d%d$"),
+	"RFC 2822 date string does not match expected format"
+)
+
+-- Extract components of the RFC 2822 string
+local day, date, month, year, time, timezone =
+	nowRfc:match("^(%a%a%a), (%d%d?) (%a%a%a) (%d%d%d%d) (%d%d:%d%d:%d%d) ([+-]%d%d%d%d)$")
+
+if not day or not date or not month or not year or not time or not timezone then
+	error("Failed to extract components from RFC 2822 date string")
+end
+
+-- Validate month
+local validMonths = {
+	Jan = true, Feb = true, Mar = true, Apr = true, May = true, Jun = true,
+	Jul = true, Aug = true, Sep = true, Oct = true, Nov = true, Dec = true,
+}
+assert(validMonths[month], "Month must be a valid RFC 2822 month abbreviation")
+
+-- Validate year
+assert(string.match(year, "^%d%d%d%d$"), "Year must be a 4-digit number")
+
+-- Validate date
+local dayNum = tonumber(date)
+assert(dayNum >= 1 and dayNum <= 31, "Date must be between 1 and 31")
+
+-- Validate time
+local hour, minute, second = time:match("^(%d%d):(%d%d):(%d%d)$")
+if not hour or not minute or not second then
+	error("Failed to extract time components from RFC 2822 date string")
+end
+
+assert(hour and tonumber(hour) >= 0 and tonumber(hour) < 24, "Hour must be between 0 and 23")
+assert(minute and tonumber(minute) >= 0 and tonumber(minute) < 60, "Minute must be between 0 and 59")
+assert(second and tonumber(second) >= 0 and tonumber(second) < 60, "Second must be between 0 and 59")
+
+-- Validate timezone
+local tzHour, tzMinute = timezone:match("^([+-]%d%d)(%d%d)$")
+if not tzHour or not tzMinute then
+	error("Failed to extract timezone components from RFC 2822 date string")
+end
+
+assert(tzHour and tonumber(tzHour) >= -14 and tonumber(tzHour) <= 14, "Timezone hour offset must be between -14 and +14")
+assert(tzMinute and tonumber(tzMinute) >= 0 and tonumber(tzMinute) < 60, "Timezone minute offset must be between 0 and 59")

types/datetime.luau

@@ -189,6 +189,24 @@ function DateTime.toIsoDate(self: DateTime): string
 	return nil :: any
 end
 
+--[=[
+	@within DateTime
+	@tag Method
+
+	Formats this `DateTime` as an RFC 2822 date-time string.
+
+	Some examples of RFC 2822 date-time strings are:
+
+	- `Fri, 21 Nov 1997 09:55:06 -0600`
+	- `Tue, 1 Jul 2003 10:52:37 +0200`
+	- `Mon, 23 Dec 2024 01:58:48 GMT`
+
+	@return string -- The RFC 2822 formatted string
+]=]
+function DateTime.toRfcDate(self: DateTime): string
+	return nil :: any
+end
+
 --[=[
 	@within DateTime
 	@tag Method
@@ -255,6 +273,9 @@ export type DateTime = typeof(DateTime)
 	-- Formats the current moment in time as an ISO 8601 string
 	print(now:toIsoDate())
 
+	-- Formats the current moment in time as an RFC 2822 string
+	print(now:toRfcDate())
+
 	-- Formats the current moment in time, using the local
 	-- time, the French locale, and the specified time string
 	print(now:formatLocalTime("%A, %d %B %Y", "fr"))
@@ -414,4 +435,28 @@ function dateTime.fromIsoDate(isoDate: string): DateTime
 	return nil :: any
 end
 
+--[=[
+	@within DateTime
+	@tag Constructor
+
+	Creates a new `DateTime` from an RFC 2822 date-time string.
+
+	### Errors
+
+	This constructor is fallible and may throw an error if the given
+	string does not strictly follow the RFC 2822 date-time string format.
+
+	Some examples of valid RFC 2822 date-time strings are:
+
+	- `Fri, 21 Nov 1997 09:55:06 -0600`
+	- `Tue, 1 Jul 2003 10:52:37 +0200`
+	- `Mon, 23 Dec 2024 01:58:48 GMT`
+
+	@param rfcDate -- An RFC 2822 formatted string
+	@return DateTime -- The new DateTime object
+]=]
+function dateTime.fromRfcDate(rfcDate: string): DateTime
+	return nil :: any
+end
+
 return dateTime