rework web server so multiple clients can be server at a time

backend/session_runtime.py

@@ -0,0 +1,132 @@
+from __future__ import annotations
+
+import re
+from pathlib import Path, PurePosixPath
+
+from backend.runtime_paths import app_data_dir, demo_dir
+
+SESSION_HEADER = "X-Argonode-Session"
+SESSION_QUERY = "session"
+SESSION_URI_PREFIX = "session://uploads/"
+
+PATH_INPUT_TYPES = {"FILE_PICKER", "FILE_PATH", "FOLDER_PICKER", "DIRECTORY"}
+
+_SESSION_ID_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9_-]{7,127}$")
+
+
+def validate_session_id(session_id: str) -> str:
+    text = str(session_id or "").strip()
+    if not _SESSION_ID_RE.fullmatch(text):
+        raise ValueError("Invalid session id")
+    return text
+
+
+def session_root_dir(session_id: str) -> Path:
+    validated = validate_session_id(session_id)
+    return app_data_dir() / "sessions" / validated
+
+
+def session_input_dir(session_id: str) -> Path:
+    return session_root_dir(session_id) / "input"
+
+
+def session_output_dir(session_id: str) -> Path:
+    return session_root_dir(session_id) / "output"
+
+
+def ensure_session_runtime_dirs(session_id: str) -> tuple[Path, Path]:
+    input_path = session_input_dir(session_id)
+    output_path = session_output_dir(session_id)
+    input_path.mkdir(parents=True, exist_ok=True)
+    output_path.mkdir(parents=True, exist_ok=True)
+    return input_path, output_path
+
+
+def normalize_relative_upload_path(raw_path: str) -> PurePosixPath:
+    raw_text = str(raw_path or "").replace("\\", "/").strip()
+    if not raw_text:
+        raise ValueError("Missing upload path")
+
+    path = PurePosixPath(raw_text)
+    if path.is_absolute():
+        raise ValueError("Upload paths must be relative")
+
+    parts: list[str] = []
+    for part in path.parts:
+        if part in ("", "."):
+            continue
+        if part == "..":
+            raise ValueError("Upload paths cannot escape the session directory")
+        if "\x00" in part:
+            raise ValueError("Upload paths cannot contain NUL bytes")
+        parts.append(part)
+
+    if not parts:
+        raise ValueError("Upload paths must contain at least one path segment")
+
+    return PurePosixPath(*parts)
+
+
+def session_upload_uri(relative_path: str | PurePosixPath) -> str:
+    normalized = normalize_relative_upload_path(str(relative_path))
+    return f"{SESSION_URI_PREFIX}{normalized.as_posix()}"
+
+
+def session_uri_to_relative_path(value: str) -> PurePosixPath | None:
+    text = str(value or "").strip()
+    if not text.startswith(SESSION_URI_PREFIX):
+        return None
+    return normalize_relative_upload_path(text[len(SESSION_URI_PREFIX):])
+
+
+def is_path_within(root: Path, candidate: Path) -> bool:
+    try:
+        candidate.resolve(strict=False).relative_to(root.resolve(strict=False))
+        return True
+    except ValueError:
+        return False
+
+
+def server_path_to_client_path(path_value: str | Path, session_id: str) -> str:
+    path = Path(path_value).expanduser().resolve(strict=False)
+    session_input = session_input_dir(session_id).resolve(strict=False)
+    if is_path_within(session_input, path):
+        rel = path.relative_to(session_input)
+        return session_upload_uri(rel.as_posix())
+    return str(path)
+
+
+def resolve_client_path(
+    value: str,
+    *,
+    session_id: str,
+    allow_local_filesystem: bool,
+) -> Path:
+    text = str(value or "").strip()
+    if not text:
+        return Path("")
+
+    rel = session_uri_to_relative_path(text)
+    if rel is not None:
+        return (session_input_dir(session_id) / Path(rel.as_posix())).resolve(strict=False)
+
+    candidate = Path(text).expanduser()
+    if not candidate.is_absolute():
+        demo_candidate = (demo_dir() / text).expanduser().resolve(strict=False)
+        if demo_candidate.exists():
+            return demo_candidate
+
+    if not candidate.is_absolute():
+        if allow_local_filesystem:
+            return candidate.resolve(strict=False)
+        raise PermissionError("Browser sessions may only use files uploaded through Browse.")
+
+    resolved = candidate.resolve(strict=False)
+    if allow_local_filesystem:
+        return resolved
+
+    session_root = session_root_dir(session_id).resolve(strict=False)
+    if is_path_within(session_root, resolved):
+        return resolved
+
+    raise PermissionError("Path is outside the current session workspace.")