mirror of
https://github.com/jointakahe/takahe.git
synced 2024-12-26 23:30:27 +00:00
81 lines
2.5 KiB
Python
81 lines
2.5 KiB
Python
import secrets
|
|
import time
|
|
|
|
|
|
class Snowflake:
|
|
"""
|
|
Snowflake ID generator and parser.
|
|
"""
|
|
|
|
# Epoch is 2022/1/1 at midnight, as these are used for _created_ times in our
|
|
# own database, not original publish times (which would need an earlier one)
|
|
EPOCH = 1641020400
|
|
|
|
TYPE_POST = 0b000
|
|
TYPE_POST_INTERACTION = 0b001
|
|
TYPE_IDENTITY = 0b010
|
|
TYPE_REPORT = 0b011
|
|
TYPE_FOLLOW = 0b100
|
|
|
|
@classmethod
|
|
def generate(cls, type_id: int) -> int:
|
|
"""
|
|
Generates a snowflake-style ID for the given "type". They are designed
|
|
to fit inside 63 bits (a signed bigint)
|
|
|
|
ID layout is:
|
|
* 41 bits of millisecond-level timestamp (enough for EPOCH + 69 years)
|
|
* 19 bits of random data (1% chance of clash at 10000 per millisecond)
|
|
* 3 bits of type information
|
|
|
|
We use random data rather than a sequence ID to try and avoid pushing
|
|
this job onto the DB - we may do that in future. If a clash does
|
|
occur, the insert will fail and Stator will retry the work for anything
|
|
that's coming in remotely, leaving us to just handle that scenario for
|
|
our own posts, likes, etc.
|
|
"""
|
|
# Get the current time in milliseconds
|
|
now: int = int((time.time() - cls.EPOCH) * 1000)
|
|
# Generate random data
|
|
rand_seq: int = secrets.randbits(19)
|
|
# Compose them together
|
|
return (now << 22) | (rand_seq << 3) | type_id
|
|
|
|
@classmethod
|
|
def get_type(cls, snowflake: int) -> int:
|
|
"""
|
|
Returns the type of a given snowflake ID
|
|
"""
|
|
if snowflake < (1 << 22):
|
|
raise ValueError("Not a valid Snowflake ID")
|
|
return snowflake & 0b111
|
|
|
|
@classmethod
|
|
def get_time(cls, snowflake: int) -> float:
|
|
"""
|
|
Returns the generation time (in UNIX timestamp seconds) of the ID
|
|
"""
|
|
if snowflake < (1 << 22):
|
|
raise ValueError("Not a valid Snowflake ID")
|
|
return ((snowflake >> 22) / 1000) + cls.EPOCH
|
|
|
|
# Handy pre-baked methods for django model defaults
|
|
@classmethod
|
|
def generate_post(cls) -> int:
|
|
return cls.generate(cls.TYPE_POST)
|
|
|
|
@classmethod
|
|
def generate_post_interaction(cls) -> int:
|
|
return cls.generate(cls.TYPE_POST_INTERACTION)
|
|
|
|
@classmethod
|
|
def generate_identity(cls) -> int:
|
|
return cls.generate(cls.TYPE_IDENTITY)
|
|
|
|
@classmethod
|
|
def generate_report(cls) -> int:
|
|
return cls.generate(cls.TYPE_REPORT)
|
|
|
|
@classmethod
|
|
def generate_follow(cls) -> int:
|
|
return cls.generate(cls.TYPE_FOLLOW)
|