Feature: Add LightNode and MessageCache

A LightNode can synchronize on a subset, or domain, of aleph.im messages. It relies on the MessageCache, which manages a message database with peewee.

Author: MHHukiewitz

.gitignore

@@ -10,6 +10,7 @@
 *.pot
 __pycache__/*
 .cache/*
+cache/**/*
 .*.swp
 */.ipynb_checkpoints/*
 

setup.cfg

@@ -43,6 +43,7 @@ install_requires =
     # Required to fix a dependency issue with parsimonious and Python3.11
     eth_abi==4.0.0b2; python_version>="3.11"
     python-magic
+    peewee
 # The usage of test_requires is discouraged, see `Dependency Management` docs
 # tests_require = pytest; pytest-cov
 # Require a specific Python version, e.g. Python 2.7 or >= 3.4

src/aleph/sdk/__init__.py

@@ -1,6 +1,6 @@
 from pkg_resources import DistributionNotFound, get_distribution
 
-from aleph.sdk.client import AlephHttpClient, AuthenticatedAlephHttpClient
+from aleph.sdk.client import AlephHttpClient, AuthenticatedAlephHttpClient, LightNode
 
 try:
     # Change here if project is renamed and does not equal the package name
@@ -11,4 +11,4 @@
 finally:
     del get_distribution, DistributionNotFound
 
-__all__ = ["AlephHttpClient", "AuthenticatedAlephHttpClient"]
+__all__ = ["AlephHttpClient", "AuthenticatedAlephHttpClient", "LightNode"]

src/aleph/sdk/client/__init__.py

@@ -1,10 +1,14 @@
 from .abstract import AlephClient, AuthenticatedAlephClient
 from .authenticated_http import AuthenticatedAlephHttpClient
 from .http import AlephHttpClient
+from .light_node import LightNode
+from .message_cache import MessageCache
 
 __all__ = [
     "AlephClient",
     "AuthenticatedAlephClient",
     "AlephHttpClient",
     "AuthenticatedAlephHttpClient",
+    "MessageCache",
+    "LightNode",
 ]

src/aleph/sdk/client/http.py

@@ -6,6 +6,7 @@
 import aiohttp
 from aleph_message import parse_message
 from aleph_message.models import AlephMessage, ItemHash, ItemType
+from aleph_message.status import MessageStatus
 from pydantic import ValidationError
 
 from ..conf import settings
@@ -178,6 +179,8 @@ async def download_file_to_buffer(
                     )
                 else:
                     raise FileTooLarge(f"The file from {file_hash} is too large")
+            else:
+                response.raise_for_status()
 
     async def download_file_ipfs_to_buffer(
         self,
@@ -343,6 +346,11 @@ async def get_message_error(
             "details": message_raw["details"],
         }
 
+    async def get_message_status(self, item_hash: str) -> MessageStatus:
+        async with self.http_session.get(f"/api/v0/messages/{item_hash}") as resp:
+            resp.raise_for_status()
+            return MessageStatus((await resp.json())["status"])
+
     async def watch_messages(
         self,
         message_filter: Optional[MessageFilter] = None,