Add datetime and timestamp fields

src/grung/examples.py

@@ -1,4 +1,4 @@
-from grung.types import BackReference, Collection, Field, Integer, Password, Record
+from grung.types import BackReference, Collection, DateTime, Field, Integer, Password, Record, Timestamp
 
 
 class User(Record):
@@ -10,6 +10,8 @@ class User(Record):
             Integer("number", default=0),
             Field("email", unique=True),
             Password("password"),
+            DateTime("created"),
+            Timestamp("last_updated"),
             BackReference("groups", Group),
         ]
 

src/grung/types.py

@@ -6,6 +6,7 @@ import os
 import re
 from collections import namedtuple
 from dataclasses import dataclass, field
+from datetime import datetime
 from typing import Dict, List
 
 import nanoid
@@ -37,7 +38,7 @@ class Field:
         if value is not None:
             return str(value)
 
-    def deserialize(self, value: value_type, db: TinyDB, recurse: bool = False) -> value_type:
+    def deserialize(self, value: str, db: TinyDB, recurse: bool = False) -> value_type:
         return value
 
 
@@ -50,6 +51,30 @@ class Integer(Field):
         return int(value)
 
 
+@dataclass
+class DateTime(Field):
+    value_type: datetime
+    default: datetime = datetime.utcfromtimestamp(0)
+
+    def serialize(self, value: value_type) -> str:
+        return (value - datetime.utcfromtimestamp(0)).total_seconds()
+
+    def deserialize(self, value: str, db: TinyDB, recurse: bool = False) -> value_type:
+        return datetime.utcfromtimestamp(int(value))
+
+    def before_insert(self, value: value_type, db: TinyDB, record: Record) -> None:
+        if not value:
+            record[self.name] = datetime.utcnow().replace(microsecond=0)
+
+
+@dataclass
+class Timestamp(DateTime):
+    value_type: datetime
+
+    def before_insert(self, value: value_type, db: TinyDB, record: Record) -> None:
+        super().before_insert(None, db, record)
+
+
 @dataclass
 class Password(Field):
     value_type = str
@@ -67,7 +92,7 @@ class Password(Field):
         try:
             if passwd[offset] != ":":
                 return False
-            digest = passwd[offset + 1 :]
+            digest = passwd[(offset + 1) :]
             if len(digest) != cls.digest_size * 2:
                 return False
             return re.match(r"^[0-9a-f]+$", digest)