Add snowflake_time utility (#105)

disagreement/__init__.py

@@ -51,7 +51,7 @@ from .errors import (
     NotFound,
 )
 from .color import Color
-from .utils import escape_markdown, escape_mentions, message_pager, utcnow
+from .utils import escape_markdown, escape_mentions, message_pager, utcnow, snowflake_time
 from .enums import (
     GatewayIntent,
     GatewayOpcode,
@@ -153,6 +153,7 @@ __all__ = [
     "escape_markdown",
     "escape_mentions",
     "message_pager",
+    "snowflake_time",
     "GatewayIntent",
     "GatewayOpcode",
     "ButtonStyle",

disagreement/utils.py

@@ -6,6 +6,9 @@ from datetime import datetime, timezone
 from typing import Any, AsyncIterator, Dict, Optional, TYPE_CHECKING
 import re
 
+# Discord epoch in milliseconds (2015-01-01T00:00:00Z)
+DISCORD_EPOCH = 1420070400000
+
 if TYPE_CHECKING:  # pragma: no cover - for type hinting only
     from .models import Message, TextChannel
 
@@ -15,6 +18,24 @@ def utcnow() -> datetime:
     return datetime.now(timezone.utc)
 
 
+def snowflake_time(snowflake: int) -> datetime:
+    """Return the creation time of a Discord snowflake.
+
+    Parameters
+    ----------
+    snowflake:
+        The snowflake ID to convert.
+
+    Returns
+    -------
+    datetime
+        The UTC timestamp embedded in the snowflake.
+    """
+
+    timestamp_ms = (snowflake >> 22) + DISCORD_EPOCH
+    return datetime.fromtimestamp(timestamp_ms / 1000, tz=timezone.utc)
+
+
 async def message_pager(
     channel: "TextChannel",
     *,

docs/utils.md

@@ -0,0 +1,20 @@
+# Utility Helpers
+
+Disagreement provides a few small utility functions for working with Discord data.
+
+## `utcnow`
+
+Returns the current timezone-aware UTC `datetime`.
+
+## `snowflake_time`
+
+Converts a Discord snowflake ID into the UTC timestamp when it was generated.
+
+```python
+from disagreement.utils import snowflake_time
+
+created_at = snowflake_time(175928847299117063)
+print(created_at.isoformat())
+```
+
+The function extracts the timestamp from the snowflake and returns a `datetime` in UTC.

mkdocs.yml

@@ -62,4 +62,5 @@ nav:
     - 'Mentions': 'mentions.md'
     - 'OAuth2': 'oauth2.md'
     - 'Presence': 'presence.md'
-    - 'Voice Client': 'voice_client.md'
+    - 'Voice Client': 'voice_client.md'
+    - 'Utility Helpers': 'utils.md'

tests/test_utils.py

@@ -1,6 +1,11 @@
-from datetime import timezone
+from datetime import datetime, timezone
 
-from disagreement.utils import escape_markdown, escape_mentions, utcnow
+from disagreement.utils import (
+    escape_markdown,
+    escape_mentions,
+    utcnow,
+    snowflake_time
+)
 
 
 def test_utcnow_timezone():
@@ -8,6 +13,13 @@ def test_utcnow_timezone():
     assert now.tzinfo == timezone.utc
 
 
+def test_snowflake_time():
+    dt = datetime(2020, 1, 1, tzinfo=timezone.utc)
+    ms = int(dt.timestamp() * 1000) - 1420070400000
+    snowflake = ms << 22
+    assert snowflake_time(snowflake) == dt
+
+
 def test_escape_markdown():
     text = "**bold** _under_ ~strike~ `code` > quote | pipe"
     escaped = escape_markdown(text)