Implement base fo caching

This adds a private module _caching that wraps both the Django caching frameworks and the ucache
libray. Both happen to expose the same (or at least sufficiently identical) API. If neither is
usable, a dummy cache class mocking the API, but doing nothing, is instantiated.

bigbluebutton/api/_caching.py

+from typing import Any, Optional
+
+try:
+    # Try importing Django app settings to find out whether we are running inside Django
+    from django.core.exceptions import ImproperlyConfigured
+    from ..django import settings as django_settings
+except (ImportError, ImproperlyConfigured):
+    USING_DJANGO = False
+else:
+    from django.core.cache import caches as django_caches
+
+    USING_DJANGO = True
+finally:
+    del ImproperlyConfigured
+
+try:
+    # Try importings ucache's most simple backend
+    from ucache import SqliteCache as UCSqliteCache
+except ImportError:
+    USING_UCACHE = False
+else:
+    USING_UCACHE = True
+
+if USING_DJANGO:
+    # Get Django cache designated by BBB_CACHE_NAME setting, or "default"
+    cache = django_caches[django_settings.CACHE_NAME]
+elif USING_UCACHE:
+    from getpass import getuser
+    from pathlib import Path
+    from tempfile import gettempdir
+
+    # Create temporary directory to hold cache data
+    tempdir = Path(gettempdir(), f"python-bigbluebutton2-{getuser()}")
+    tempdir.mkdir(mode=0o700, parents=True, exist_ok=True)
+
+    cache = UCSqliteCache(str(tempdir.joinpath("cache.sqlite")))
+else:
+    # No caching backend found, make caching a no-op
+    class DummyCache:
+        def _dummy(self, *args, **lwargs) -> None:
+            return
+
+        get = _dummy
+        get_many = _dummy
+        set = _dummy
+        set_many = _dummy
+        delete = _dummy
+        delete_many = _dummy
+        flush = _dummy
+        clean_expired = _dummy
+
+        __getitem__ = get
+        __setitem__ = set
+        __delitem__ = delete
+
+    cache = DummyCache()

bigbluebutton/api/attendee.py

@@ -6,6 +6,7 @@ from dataclasses import dataclass, field
 from enum import Enum
 from typing import TYPE_CHECKING, Any, Dict, Optional
 
+from ._caching import cache
 from .util import camel_to_snake, snake_to_camel, to_field_type
 
 if TYPE_CHECKING:  # pragma: no cover

bigbluebutton/api/bigbluebutton.py

@@ -22,6 +22,7 @@ from uuid import uuid1
 import requests
 import xmltodict
 
+from ._caching import cache
 from .attendee import Attendee
 from .loadbalancing import CHECKERS as lb_checkers
 from .meeting import Meeting

bigbluebutton/api/meeting.py

@@ -4,6 +4,7 @@ import logging
 from dataclasses import dataclass, field
 from typing import TYPE_CHECKING, Any, Dict, Optional
 
+from ._caching import cache
 from .attendee import Attendee
 from .util import camel_to_snake, snake_to_camel, to_field_type
 

bigbluebutton/django/settings.py

@@ -24,3 +24,5 @@ USER_ID_CALLBACK = import_string(
 ROLE_CALLBACK = import_string(
     getattr(_settings, f"{_PREFIX}_ROLE_CALLBACK", "bigbluebutton.django.util.get_role")
 )
+
+CACHE_NAME = getattr(_settings, f"{_PREFIX}_CACHE_NAME", "default")

poetry.lock

@@ -534,6 +534,14 @@ optional = false
 python-versions = "*"
 version = "5.4.5"
 
+[[package]]
+category = "main"
+description = "a little orm"
+name = "peewee"
+optional = true
+python-versions = "*"
+version = "3.13.3"
+
 [[package]]
 category = "dev"
 description = "plugin and hook calling mechanisms for python"
@@ -1020,6 +1028,14 @@ version = "2.1"
 [package.dependencies]
 pytz = "*"
 
+[[package]]
+category = "main"
+description = "lightweight and efficient caching library"
+name = "ucache"
+optional = true
+python-versions = "*"
+version = "0.1.4"
+
 [[package]]
 category = "main"
 description = "HTTP library with thread-safe connection pooling, file post, and more."
@@ -1063,12 +1079,13 @@ docs = ["sphinx", "jaraco.packaging (>=3.2)", "rst.linker (>=1.9)"]
 testing = ["jaraco.itertools", "func-timeout"]
 
 [extras]
+caching = ["ucache", "peewee"]
 cli = ["click", "toml", "tabulate"]
 django = ["dicttoxml", "django"]
 sysstat = ["sadf"]
 
 [metadata]
-content-hash = "5aadc276268bfd2164e4162aff25813b2211483da339ab438ba8cc78135a536b"
+content-hash = "ac17d9cc14afbb5058f3099a1a0effc1e126c841d8cba57f9712b38cafe8c73b"
 python-versions = "^3.6"
 
 [metadata.files]
@@ -1364,6 +1381,9 @@ pbr = [
     {file = "pbr-5.4.5-py2.py3-none-any.whl", hash = "sha256:579170e23f8e0c2f24b0de612f71f648eccb79fb1322c814ae6b3c07b5ba23e8"},
     {file = "pbr-5.4.5.tar.gz", hash = "sha256:07f558fece33b05caf857474a366dfcc00562bca13dd8b47b2b3e22d9f9bf55c"},
 ]
+peewee = [
+    {file = "peewee-3.13.3.tar.gz", hash = "sha256:1269a9736865512bd4056298003aab190957afe07d2616cf22eaf56cb6398369"},
+]
 pluggy = [
     {file = "pluggy-0.13.1-py2.py3-none-any.whl", hash = "sha256:966c145cd83c96502c3c3868f50408687b38434af77734af1e9ca461a4081d2d"},
     {file = "pluggy-0.13.1.tar.gz", hash = "sha256:15b2acde666561e1298d71b523007ed7364de07029219b604cf808bfa1c765b0"},
@@ -1603,6 +1623,9 @@ tzlocal = [
     {file = "tzlocal-2.1-py2.py3-none-any.whl", hash = "sha256:e2cb6c6b5b604af38597403e9852872d7f534962ae2954c7f35efcb1ccacf4a4"},
     {file = "tzlocal-2.1.tar.gz", hash = "sha256:643c97c5294aedc737780a49d9df30889321cbe1204eac2c2ec6134035a92e44"},
 ]
+ucache = [
+    {file = "ucache-0.1.4.tar.gz", hash = "sha256:f2f3d6c10d036d1fdd297d08372586d7868a5ac748da6def38f5e8d7cf6238b1"},
+]
 urllib3 = [
     {file = "urllib3-1.25.9-py2.py3-none-any.whl", hash = "sha256:88206b0eb87e6d677d424843ac5209e3fb9d0190d0ee169599165ec25e9d9115"},
     {file = "urllib3-1.25.9.tar.gz", hash = "sha256:3018294ebefce6572a474f0604c2021e33b3fd8006ecd11d62107a5d2a963527"},

pyproject.toml

@@ -40,6 +40,8 @@ sadf = { version = "^0.1.2", optional = true }
 django = {version = "^3.0.6", optional = true}
 dicttoxml = {version = "^1.7.4", optional = true}
 defusedxml = "^0.6.0"
+ucache = {version = "^0.1.4", optional = true}
+peewee = {version = "^3.13.3", optional = true}
 
 [tool.poetry.dev-dependencies]
 pytest = "^5.4.2"
@@ -65,6 +67,7 @@ sphinxcontrib-django = "^0.5.1"
 [tool.poetry.extras]
 cli = ["click", "toml", "tabulate", "xdg"]
 django = ["dicttoxml", "django"]
+caching = ["ucache", "peewee"]
 sysstat = ["sadf"]
 
 [tool.poetry.scripts]

tox.ini

@@ -7,7 +7,7 @@ envlist = py38
 whitelist_externals = poetry
 skip_install = true
 envdir = {toxworkdir}/globalenv
-commands_pre = poetry install -E cli -E django -E sysstat
+commands_pre = poetry install -E cli -E django -E sysstat -E caching
 commands =
     poetry run pytest --doctest-modules --cov-report=term-missing --cov=bigbluebutton/ {posargs} bigbluebutton/ tests/