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kvmd/clients/pst.py

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+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main PiKVM daemon.                                           #
+#                                                                            #
+#    Copyright (C) 2020  Maxim Devaev <mdevaev@gmail.com>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import os
+import contextlib
+
+from typing import AsyncGenerator
+
+import aiohttp
+
+from .. import htclient
+from .. import htserver
+
+
+# =====
+class PstError(Exception):
+    pass
+
+
+# =====
+class PstClient:
+    def __init__(
+        self,
+        subdir: str,
+        unix_path: str,
+        timeout: float,
+        user_agent: str,
+    ) -> None:
+
+        self.__subdir = subdir
+        self.__unix_path = unix_path
+        self.__timeout = timeout
+        self.__user_agent = user_agent
+
+    async def get_path(self) -> str:
+        async with self.__make_http_session() as session:
+            async with session.get("http://localhost:0/state") as resp:
+                htclient.raise_not_200(resp)
+                path = (await resp.json())["result"]["data"]["path"]
+                return os.path.join(path, self.__subdir)
+
+    @contextlib.asynccontextmanager
+    async def writable(self) -> AsyncGenerator[str, None]:
+        async with self.__inner_writable() as path:
+            path = os.path.join(path, self.__subdir)
+            if not os.path.exists(path):
+                os.mkdir(path)
+            yield path
+
+    @contextlib.asynccontextmanager
+    async def __inner_writable(self) -> AsyncGenerator[str, None]:
+        async with self.__make_http_session() as session:
+            async with session.ws_connect("http://localhost:0/ws") as ws:
+                path = ""
+                async for msg in ws:
+                    if msg.type != aiohttp.WSMsgType.TEXT:
+                        raise PstError(f"Unexpected message type: {msg!r}")
+                    (event_type, event) = htserver.parse_ws_event(msg.data)
+                    if event_type == "storage_state":
+                        if not event["data"]["write_allowed"]:
+                            raise PstError("Write is not allowed")
+                        path = event["data"]["path"]
+                        break
+                if not path:
+                    raise PstError("WS loop broken without write_allowed=True flag")
+                # TODO: Actually we should follow ws events, but for fast writing we can safely ignore them
+                yield path
+
+    def __make_http_session(self) -> aiohttp.ClientSession:
+        return aiohttp.ClientSession(
+            headers={"User-Agent": self.__user_agent},
+            connector=aiohttp.UnixConnector(path=self.__unix_path),
+            timeout=aiohttp.ClientTimeout(total=self.__timeout),
+        )