Change: Message.time was float, becomes datetime (#40)

* Change: Message.time was float, becomes datetime

Change the type if BaseMessage.time to a datetime. This allows easier manipulation of the field, and parsing from strings as well as floats.

New APIs introduced in PyAleph 0.5.0 store the message time as timestampz and return it as ISO strings. This changes is compatible with both the old and new APIs.

* Add time validator for auto-conversion from float to datetime

* Fix missing parameter

* Fix Dockerfile dependency installation

* Fix typing issues with mypy by using a generic type for AlephMessage

* Rename to convert_float_to_datetime

Co-authored-by: Hugo Herter <[email protected]>

---------

Co-authored-by: mhh <[email protected]>
Co-authored-by: Mike Hukiewitz <[email protected]>

aleph_message/models/__init__.py

@@ -1,3 +1,4 @@
+import datetime
 import json
 from copy import copy
 from enum import Enum
@@ -11,7 +12,7 @@
     Literal,
     Optional,
     Type,
-    Union,
+    Union, TypeVar, cast,
 )
 
 from pydantic import BaseModel, Extra, Field, validator
@@ -203,7 +204,7 @@ class BaseMessage(BaseModel):
     size: Optional[int] = Field(
         default=None, description="Size of the content"
     )  # Almost always present
-    time: float = Field(description="Unix timestamp when the message was published")
+    time: datetime.datetime = Field(description="Unix timestamp or datetime when the message was published")
     item_type: ItemType = Field(description="Storage method used for the content")
     item_content: Optional[str] = Field(
         default=None,
@@ -265,6 +266,13 @@ def check_confirmed(cls, v, values):
             raise ValueError("Message cannot be 'confirmed' without 'confirmations'")
         return v
 
+    @validator("time")
+    def convert_float_to_datetime(cls, v, values):
+        if isinstance(v, float):
+            v = datetime.datetime.fromtimestamp(v)
+        assert isinstance(v, datetime.datetime)
+        return v
+
     class Config:
         extra = Extra.forbid
         exclude = {"id_", "_id"}
@@ -334,14 +342,10 @@ class InstanceMessage(BaseMessage):
     ForgetMessage,
 ]
 
-AlephMessageType: TypeAlias = Union[
-    Type[PostMessage],
-    Type[AggregateMessage],
-    Type[StoreMessage],
-    Type[ProgramMessage],
-    Type[InstanceMessage],
-    Type[ForgetMessage],
-]
+
+T = TypeVar('T', bound=AlephMessage)
+
+AlephMessageType: TypeAlias = Type[T]
 
 message_classes: List[AlephMessageType] = [
     PostMessage,
@@ -383,16 +387,16 @@ def add_item_content_and_hash(message_dict: Dict, inplace: bool = False):
 
 def create_new_message(
     message_dict: Dict,
-    factory: Optional[AlephMessageType] = None,
-) -> AlephMessage:
+    factory: Optional[Type[T]] = None,
+) -> T:
     """Create a new message from a dict.
     Computes the 'item_content' and 'item_hash' fields.
     """
     message_content = add_item_content_and_hash(message_dict)
     if factory:
-        return factory.parse_obj(message_content)
+        return cast(T, factory.parse_obj(message_content))
     else:
-        return parse_message(message_content)
+        return cast(T, parse_message(message_content))
 
 
 def create_message_from_json(

aleph_message/tests/test_models.py

@@ -25,7 +25,7 @@
     create_message_from_file,
     create_message_from_json,
     create_new_message,
-    parse_message,
+    parse_message, AlephMessage,
 )
 from aleph_message.tests.download_messages import MESSAGES_STORAGE_PATH
 
@@ -87,7 +87,7 @@ def test_messages_last_page():
         if message_dict["item_hash"] in HASHES_TO_IGNORE:
             continue
 
-        message = parse_message(message_dict)
+        message: AlephMessage = parse_message(message_dict)
         assert message
 
 
@@ -285,9 +285,14 @@ def test_create_new_message():
         "signature": "0x123456789",  # Signature validation requires using aleph-client
     }
 
-    new_message_1 = create_new_message(message_dict, factory=PostMessage)
+    new_message_1: PostMessage = create_new_message(message_dict, factory=PostMessage)
     assert new_message_1
     assert new_message_1.type == MessageType.post
+    # Check that the time was converted to a datetime
+    assert new_message_1.time.isoformat() == '2021-07-07T10:04:47.017000+00:00'
+
+    # The time field can be either a float or a datetime as string
+    message_dict["time"] = '2021-07-07T10:04:47.017000+00:00'
     new_message_2 = create_message_from_json(
         json.dumps(message_dict), factory=PostMessage
     )
@@ -303,7 +308,7 @@ def test_messages_from_disk():
             data_dict = json.load(page_fd)
         for message_dict in data_dict["messages"]:
             try:
-                message = parse_message(message_dict)
+                message: AlephMessage = parse_message(message_dict)
                 assert message
             except ValidationError as e:
                 console.print("-" * 79)