feat: add servicelink RPC mesh endpoint

- Add the servicelink submodule and register POST /rpc for node-to-node file operations.
- Require bearer tokens with the mesh scope and apply rate/body-size limits to RPC calls.
- Map database connectivity failures to the existing 504 database error flow, with JSON responses for API routes.
- Cover the new RPC handlers and database error handling with focused pytest tests.
- Bump the NanoShare package version to 1.21.0.

tests/test_database_error_handler.py

@@ -0,0 +1,119 @@
+import asyncio
+import importlib.util
+import sys
+import types
+from pathlib import Path
+
+import httpx
+from quart import Blueprint, Quart, request
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+
+class FakeLimiter:
+  def exempt(self, func):
+    return func
+
+  def limit(self, *_args, **_kwargs):
+    def decorator(func):
+      return func
+    return decorator
+
+class FakeLogger:
+  def __init__(self):
+    self.errors = []
+
+  def error(self, message):
+    self.errors.append(message)
+
+  def warning(self, message):
+    pass
+
+class FailingConvex:
+  async def get_current_favicon(self):
+    raise httpx.ConnectError("[Errno -2] Name or service not known")
+
+def load_module(module_name, module_path):
+  spec = importlib.util.spec_from_file_location(module_name, module_path)
+  module = importlib.util.module_from_spec(spec)
+  sys.modules[module_name] = module
+  spec.loader.exec_module(module)
+  return module
+
+def install_route_test_modules(monkeypatch, app, logger):
+  fake_setup = types.ModuleType("my_modules.app.setup")
+  fake_setup.app = app
+  fake_setup.LIMITER = FakeLimiter()
+  monkeypatch.setitem(sys.modules, "my_modules.app.setup", fake_setup)
+
+  fake_constens = types.ModuleType("my_modules.app.constens")
+  fake_constens.BLOCKED_IPS_ACCESSING_TIMES = 3
+  fake_constens.BLOCKED_IPS_STORED_TIMEFRAME = 60
+  monkeypatch.setitem(sys.modules, "my_modules.app.constens", fake_constens)
+
+  fake_logger_module = types.ModuleType("my_modules.app.logger")
+  fake_logger_module.logger = logger
+  monkeypatch.setitem(sys.modules, "my_modules.app.logger", fake_logger_module)
+
+  fake_functions = types.ModuleType("my_modules.functions")
+  fake_functions.get_ip = lambda: "203.0.113.10"
+  fake_functions.enforce_custom_limit = lambda *_args, **_kwargs: None
+  fake_functions.get_request_context = lambda: types.SimpleNamespace(path=request.path)
+  fake_functions.is_valid_uuid = lambda value: True
+  monkeypatch.setitem(sys.modules, "my_modules.functions", fake_functions)
+
+def register_template_routes(app):
+  side_main = Blueprint("side_main", __name__)
+
+  async def index():
+    return "ok"
+
+  side_main.add_url_rule("/", "index", index)
+  side_main.add_url_rule("/files", "files_list", index)
+  side_main.add_url_rule("/access", "access_list", index)
+  app.register_blueprint(side_main)
+
+  auth_login = Blueprint("auth_login", __name__)
+  auth_login.add_url_rule("/login", "login", index)
+  auth_login.add_url_rule("/logout", "logout", index)
+  app.register_blueprint(auth_login)
+
+
+def load_errors_and_basics(monkeypatch, app):
+  logger = FakeLogger()
+  install_route_test_modules(monkeypatch, app, logger)
+  root = Path(__file__).resolve().parents[1]
+  errors = load_module("test_routes_handeling_errorsAndBots", root / "routes" / "handeling" / "errorsAndBots.py")
+  basics = load_module("test_routes_handeling_basics", root / "routes" / "handeling" / "basics.py")
+  return errors, basics, logger
+
+def test_convex_connect_error_is_returned_as_global_database_error(monkeypatch):
+  async def run_test():
+    app = Quart(__name__, template_folder=str(Path(__file__).resolve().parents[1] / "templates" / "side"))
+    register_template_routes(app)
+    app.convex = FailingConvex()
+    _errors, basics, logger = load_errors_and_basics(monkeypatch, app)
+    app.register_blueprint(basics.basic_bp)
+
+    response = await app.test_client().get("/favicon.ico")
+
+    assert response.status_code == 504
+    assert any("Name or service not known" in str(error) for error in logger.errors)
+
+  asyncio.run(run_test())
+
+def test_api_convex_connect_error_returns_json_database_error(monkeypatch):
+  async def run_test():
+    app = Quart(__name__, template_folder=str(Path(__file__).resolve().parents[1] / "templates" / "side"))
+    load_errors_and_basics(monkeypatch, app)
+
+    @app.get("/api/failing")
+    async def failing_api():
+      raise httpx.ConnectError("[Errno -2] Name or service not known")
+
+    response = await app.test_client().get("/api/failing")
+    payload = await response.get_json()
+
+    assert response.status_code == 504
+    assert payload["error"] == "Database Error"
+
+  asyncio.run(run_test())