feat(files): API tokens — a machine reaches the library folder by folder

A user can make a token for a machine of theirs (`/api/tokens`, signed-in only): `sfl_` + 32
random bytes + a checksum, only its SHA-256 kept, shown once. Sent as a Bearer header it is
honoured on six `/api/files` routes only — folders, list, file, hash, upload, delete — and there
only in the folders its grants name, with the rights they give (list / read / write / delete).
One check, `FilesCaller.may`, in every route; a folder or file out of reach answers like a
missing one; the files shared with the user are never in reach. A token beats a cookie on the
same request.

The Hub preset makes the user's one Hub folder (a new folder kind) and grants it every right.
Refused tokens are slowed down per client, a runaway machine per token; last use is stamped at
most once a minute; making and revoking a token is audited, and a token's uploads and deletes
name it in their audit rows.

backend/app/README.md

@@ -20,7 +20,8 @@ Three layers, by *who* runs the code — not by feature:
    run by both the admin route and the scheduler; `downloads/pipeline.py` is the worker's child pipeline;
    `issues/bundle.py` is the one definition of a bug report's files, for the zip export and the tracker.
 
-3. **Flat `app/*.py` core modules — cross-cutting primitives.** `auth`, `sysconfig`, `quota`, `audit`,
+3. **Flat `app/*.py` core modules — cross-cutting primitives.** `auth` (with `apitokens`, a machine's
+   folder-scoped way into the Files library), `sysconfig`, `quota`, `audit`,
    `notifications`, `userscope`, `ratelimit`, `progress`, `logs` (the one logging
    configuration), `logsink` (its `log_events` table), `diagnostics` (a user's consented log
    level), `debugsession` (a recording that tags its user's lines, E16) and `collation` (A→Z in the

backend/app/apitokens.py

@@ -0,0 +1,209 @@
+"""Machine access to the Files library: API tokens, and what each one may do where.
+
+A user makes a token for a machine of theirs — their hub, a script — and it reaches their library as
+`Authorization: Bearer sfl_…`. Only on `/api/files`: the routes there take `files_caller` instead of
+`current_user`, and nothing else does (a test holds the route table to that), so a token can never
+manage the account, the tokens, or anything outside the library. And only in the folders its grants
+name, with the rights they give: list, read, write, delete. Every route asks the one question,
+`FilesCaller.may(folder_id, right)`; a signed-in user may everything in their own folders.
+
+The token is `sfl_` + 32 random bytes in base62 + a CRC32 of them: a mistyped or cut-off token is
+refused without a database read, and a secret scanner can tell one by its shape. Only its SHA-256 is
+kept (`security.hash_token`) — the user sees it once, when it is made — with its first characters to
+tell tokens apart by. It is looked up by that hash on every request: no signed claims, so a deleted
+token stops working at once.
+"""
+
+import secrets
+import zlib
+from collections.abc import Mapping
+from dataclasses import dataclass
+from datetime import datetime, timedelta, timezone
+from enum import StrEnum
+
+from fastapi import Depends, Request
+from sqlalchemy import or_, select, update
+from sqlalchemy.orm import Session
+
+from app import debugsession, logs
+from app.auth import current_user
+from app.db import get_db
+from app.models import ApiToken, ApiTokenGrant, User
+from app.ratelimit import RateLimiter, client_key
+from app.refusal import refused
+from app.security import hash_token
+
+log = logs.get_logger(__name__)
+
+PREFIX = "sfl_"
+_ALPHABET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+_BODY_BYTES = 32
+_BODY_LEN = 43  # 62**43 > 2**256: every 32-byte value fits
+_CHECK_LEN = 6  # 62**6 > 2**32: every CRC32 fits
+TOKEN_LEN = len(PREFIX) + _BODY_LEN + _CHECK_LEN
+# What a token is shown by once it is made: enough to tell a user's tokens apart, far too little to
+# narrow a guess (8 of its 43 random characters).
+SHOWN_LEN = len(PREFIX) + 8
+
+# A machine that runs away (a loop in a script) is held back per token; a caller trying tokens is
+# held back per client, counting only the refusals.
+_calls = RateLimiter(600, 60)
+_bad = RateLimiter(20, 300)
+# How stale `last_used_at` may get before a request writes it again: a busy script costs one write a
+# minute, not one per request.
+_TOUCH_EVERY = timedelta(minutes=1)
+
+
+class Right(StrEnum):
+    LIST = "list"
+    READ = "read"
+    WRITE = "write"
+    DELETE = "delete"
+
+
+# Each right's column on a grant. A dict over the enum, so a new right without a column fails here.
+GRANT_COLUMNS = {
+    Right.LIST: "can_list",
+    Right.READ: "can_read",
+    Right.WRITE: "can_write",
+    Right.DELETE: "can_delete",
+}
+
+
+def _b62(value: int, width: int) -> str:
+    out = []
+    for _ in range(width):
+        value, digit = divmod(value, 62)
+        out.append(_ALPHABET[digit])
+    return "".join(reversed(out))
+
+
+def _check(body: str) -> str:
+    return _b62(zlib.crc32(body.encode()), _CHECK_LEN)
+
+
+def mint() -> str:
+    """A new token, in full. The caller stores its hash and shows it to the user, once."""
+    body = _b62(int.from_bytes(secrets.token_bytes(_BODY_BYTES)), _BODY_LEN)
+    return PREFIX + body + _check(body)
+
+
+def well_formed(raw: str) -> bool:
+    """Whether `raw` has a token's shape and its checksum adds up."""
+    if len(raw) != TOKEN_LEN or not raw.startswith(PREFIX):
+        return False
+    body, check = raw[len(PREFIX) : -_CHECK_LEN], raw[-_CHECK_LEN:]
+    if any(c not in _ALPHABET for c in body):
+        return False
+    return secrets.compare_digest(_check(body), check)
+
+
+def grant_rights(grant: ApiTokenGrant) -> frozenset[Right]:
+    return frozenset(r for r, col in GRANT_COLUMNS.items() if getattr(grant, col))
+
+
+@dataclass(frozen=True)
+class FilesCaller:
+    """Who is asking the Files library, and where they may do what. `grants` is None for a signed-in
+    user (everything in their own folders); for a token, folder id → its rights there."""
+
+    user: User
+    token_id: int | None = None
+    token_prefix: str | None = None
+    grants: Mapping[int, frozenset[Right]] | None = None
+
+    def may(self, folder_id: int | None, right: Right) -> bool:
+        if self.grants is None:
+            return True
+        return folder_id is not None and right in self.grants.get(folder_id, frozenset())
+
+    def folders_with(self, right: Right) -> set[int] | None:
+        """The folders `right` is granted in; None = any of the user's own."""
+        if self.grants is None:
+            return None
+        return {f for f, rights in self.grants.items() if right in rights}
+
+    @property
+    def via(self) -> str | None:
+        """How an audit row says a token did it, None when the user did."""
+        return None if self.token_prefix is None else f"api token {self.token_prefix}…"
+
+
+def bearer_token(request: Request) -> str | None:
+    """The token of an `Authorization: Bearer` header; None when the request carries none (another
+    scheme counts as none — it is not ours to judge)."""
+    scheme, _, value = request.headers.get("authorization", "").partition(" ")
+    if scheme.lower() != "bearer":
+        return None
+    return value.strip()
+
+
+def session_caller(request: Request, db: Session = Depends(get_db)) -> User | None:
+    """The signed-in user, or None when the request brings a token instead: a token wins over a
+    cookie, so a machine's request is judged by its grants alone, whatever else it carries."""
+    if bearer_token(request) is not None:
+        return None
+    return current_user(request, db)
+
+
+def files_caller(
+    request: Request,
+    db: Session = Depends(get_db),
+    user: User | None = Depends(session_caller),
+) -> FilesCaller:
+    """The `/api/files` caller: a signed-in user, or a valid token's user with its grants."""
+    if user is not None:
+        return FilesCaller(user=user)
+    return _token_caller(request, db, bearer_token(request) or "")
+
+
+def _refuse_token(key: str, reason: str) -> Exception:
+    _bad.allow(key)
+    log.info(
+        "a request brought an API token that does not hold",
+        extra=logs.event("apitoken.refused", reason=reason),
+    )
+    return refused(401, "not_authenticated")
+
+
+def _token_caller(request: Request, db: Session, raw: str) -> FilesCaller:
+    key = client_key(request)
+    if _bad.exhausted(key):
+        raise refused(429, "api_token_rate_limited")
+    if not well_formed(raw):
+        raise _refuse_token(key, "malformed")
+    token = db.execute(
+        select(ApiToken).where(ApiToken.token_hash == hash_token(raw))
+    ).scalar_one_or_none()
+    if token is None:
+        raise _refuse_token(key, "unknown")
+    now = datetime.now(timezone.utc)
+    if token.expires_at is not None and token.expires_at <= now:
+        raise _refuse_token(key, "expired")
+    user = db.get(User, token.user_id)
+    if user is None or not user.is_active or user.is_suspended:
+        raise _refuse_token(key, "account")
+    if not _calls.allow(str(token.id)):
+        raise refused(429, "api_token_rate_limited")
+    grants = {
+        g.folder_id: grant_rights(g)
+        for g in db.execute(select(ApiTokenGrant).where(ApiTokenGrant.token_id == token.id))
+        .scalars()
+        .all()
+    }
+    caller = FilesCaller(user=user, token_id=token.id, token_prefix=token.prefix, grants=grants)
+    db.execute(
+        update(ApiToken)
+        .where(
+            ApiToken.id == token.id,
+            or_(ApiToken.last_used_at.is_(None), ApiToken.last_used_at < now - _TOUCH_EVERY),
+        )
+        .values(last_used_at=now)
+        .execution_options(synchronize_session=False)
+    )
+    # Committed here, ahead of the route: a read-only route never commits, and a write route must
+    # not carry this along into a rollback of its own.
+    db.commit()
+    logs.set_user(user.id, *debugsession.level_for(user, None))
+    request.state.user_id = user.id
+    return caller

backend/app/audit.py

@@ -69,6 +69,10 @@ class AuditAction:
     FILE_FOLDER_RENAME = "file_folder_rename"
     FILE_FOLDER_RETENTION = "file_folder_retention"
     FILE_FOLDER_DELETE = "file_folder_delete"
+    # A machine's token to the library (`routes.tokens`): made (its folders and rights) or revoked.
+    # What a token then did is the file rows above, their summary naming it.
+    API_TOKEN_CREATE = "api_token_create"
+    API_TOKEN_REVOKE = "api_token_revoke"
 
 
 def record(

backend/app/downloads/folders.py

@@ -7,6 +7,9 @@ shared asset can be held by several users), so a rename or a move is a column up
   uploads, one per other site). Its `source_key` names the origin; the client renders its name
   from the key, in the reader's language.
 - an OWN folder is the user's, with the name they gave it.
+- the HUB folder (one per user, made when they first give a machine a token for it, `hub_folder`) is
+  where they swap files with that machine. Its name, like a source folder's, is the client's; a file
+  may be moved in like into an own folder, and it keeps a file until it is deleted.
 
 Every file of a user is in exactly one folder. The folder a new file lands in is decided here
 (`source_key_for` + `source_folder`), at every place a job is created, so the rule lives once. A file
@@ -35,6 +38,7 @@ from app.models import DownloadJob, FileFolder, MediaAsset
 class FolderKind(StrEnum):
     SOURCE = "source"
     OWN = "own"
+    HUB = "hub"
 
 
 class SourceKey(StrEnum):
@@ -123,6 +127,26 @@ def source_folder(db: Session, user_id: int, key: str) -> FileFolder:
     return folder
 
 
+def hub_folder(db: Session, user_id: int) -> FileFolder:
+    """The user's Hub folder, made on first use; a race on its one-per-user index is settled like
+    `source_folder`'s."""
+    stmt = select(FileFolder).where(
+        FileFolder.user_id == user_id, FileFolder.kind == FolderKind.HUB
+    )
+    folder = db.execute(stmt).scalar_one_or_none()
+    if folder is not None:
+        return folder
+    folder = FileFolder(user_id=user_id, kind=FolderKind.HUB)
+    try:
+        with db.begin_nested():
+            db.add(folder)
+            db.flush()
+    # silent-ok: another request made the Hub folder first; re-selecting it is the whole handling.
+    except IntegrityError:
+        folder = db.execute(stmt).scalar_one()
+    return folder
+
+
 def place(db: Session, job: DownloadJob) -> None:
     """Put a new job's file in its source folder, and record that origin on it. Called wherever a
     job is created; the job must carry its `user_id`, `source_kind` and source refs already."""

backend/app/downloads/upload.py

@@ -57,12 +57,14 @@ def ingest_upload(
     display_name: str | None = None,
     sha256: str | None = None,
     folder_id: int | None = None,
+    via: str | None = None,
 ) -> DownloadJob:
     """Ingest an already-uploaded file at `src_path` into `user_id`'s library and return its job —
     `done`, or `queued` for the worker's phone-safe conversion (see the module docstring). `src_path`
     is MOVED into place on success (the caller stages it to a temp file first). `sha256` is the
     hash of those bytes, when the caller took it on the way in; `folder_id` the folder it asked for
-    (`folders.upload_target`), else its Uploads folder.
+    (`folders.upload_target`), else its Uploads folder; `via` what the audit row names as the doer
+    when it was not the user themselves (an API token).
 
     Raises folders.FolderError when that folder is not one an upload may land in (or is gone).
 
@@ -145,7 +147,14 @@ def ingest_upload(
             folders.stamp_done(db, job)
         service.incr_ref_count(db, asset.id)
         db.flush()
-        audit.record(db, user_id, AuditAction.FILE_UPLOAD, target_type="file", target_id=job.id)
+        audit.record(
+            db,
+            user_id,
+            AuditAction.FILE_UPLOAD,
+            target_type="file",
+            target_id=job.id,
+            summary=via,
+        )
         db.commit()
     except Exception:
         db.rollback()

backend/app/main.py

@@ -58,6 +58,7 @@ from app.routes import (  # noqa: E402 — logging is configured first
     setup as setup_routes,
     sync,
     tags,
+    tokens as tokens_routes,
     version,
 )
 from app.scheduler import shutdown_scheduler, start_scheduler  # noqa: E402 — logging is configured first
@@ -337,6 +338,7 @@ app.include_router(plex_routes.router)
 app.include_router(downloads.router)
 app.include_router(downloads.admin_router)
 app.include_router(files_routes.router)
+app.include_router(tokens_routes.router)
 app.include_router(public_routes.router)
 app.include_router(admin.router)
 app.include_router(config_routes.router)

backend/app/models.py

@@ -919,7 +919,8 @@ class FileFolder(Base, TimestampMixin):
     """A folder of the Files library (`app.downloads.folders`): a row, never a directory.
 
     A SOURCE folder (`source_key` set: youtube / plex / upload / site:<host>) is made the first time a
-    user gets a file from that origin; an OWN folder (`name` set) is one the user made. Every file —
+    user gets a file from that origin; an OWN folder (`name` set) is one the user made; the HUB folder
+    (neither set, one per user) is where they swap files with a machine of theirs. Every file —
     a `DownloadJob` — sits in exactly one (`DownloadJob.folder_id`). `retention_days` is how long a
     file stays once done (NULL = until deleted); a file's own `expires_at` is stamped from it."""
 
@@ -933,9 +934,12 @@ class FileFolder(Base, TimestampMixin):
             unique=True,
             postgresql_where=text("name IS NOT NULL"),
         ),
+        # One Hub folder per user.
+        Index("uq_file_folder_hub", "user_id", unique=True, postgresql_where=text("kind = 'hub'")),
         CheckConstraint(
             "(kind = 'source' AND source_key IS NOT NULL AND name IS NULL)"
-            " OR (kind = 'own' AND name IS NOT NULL AND source_key IS NULL)",
+            " OR (kind = 'own' AND name IS NOT NULL AND source_key IS NULL)"
+            " OR (kind = 'hub' AND name IS NULL AND source_key IS NULL)",
             name="ck_file_folder_kind",
         ),
     )
@@ -949,6 +953,45 @@ class FileFolder(Base, TimestampMixin):
     retention_days: Mapped[int | None] = mapped_column(Integer)
 
 
+class ApiToken(Base, TimestampMixin):
+    """A user's token for a machine to reach their Files library with (`app.apitokens`): sent as
+    `Authorization: Bearer sfl_…`, honoured on `/api/files` only, and only in the folders its
+    grants name. Only the SHA-256 of the token is kept — it is shown once, when it is made — plus
+    its first characters (`prefix`), so the user can tell their tokens apart."""
+
+    __tablename__ = "api_tokens"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"), index=True)
+    name: Mapped[str] = mapped_column(String(80))
+    prefix: Mapped[str] = mapped_column(String(16))
+    token_hash: Mapped[str] = mapped_column(String(64), unique=True)
+    expires_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))  # NULL = never
+    last_used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+
+
+class ApiTokenGrant(Base):
+    """What one token may do in one folder. A folder with no grant is out of the token's reach."""
+
+    __tablename__ = "api_token_grants"
+    __table_args__ = (
+        UniqueConstraint("token_id", "folder_id", name="uq_api_token_grant"),
+        CheckConstraint(
+            "can_list OR can_read OR can_write OR can_delete", name="ck_api_token_grant_some"
+        ),
+    )
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    token_id: Mapped[int] = mapped_column(ForeignKey("api_tokens.id", ondelete="CASCADE"))
+    folder_id: Mapped[int] = mapped_column(
+        ForeignKey("file_folders.id", ondelete="CASCADE"), index=True
+    )
+    can_list: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
+    can_read: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
+    can_write: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
+    can_delete: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
+
+
 def _ready_on_insert(context) -> datetime | None:
     """A job inserted already done (an upload kept as it came) was ready the moment it was made; one
     that becomes done later is stamped then (`folders.stamp_done`, `service.finalize_if_running`)."""

backend/app/routes/files.py

@@ -7,6 +7,11 @@ bytes. Folders are rows (`downloads.folders`), so a rename or a move never touch
 In-flight jobs are not here: they are the download tray's (`routes.downloads`). The helpers above
 the routes are shared with that module — serialization, the ownership locks, the upload spool —
 because a download and a library file are one row at two moments.
+
+A machine with an API token (`app.apitokens`) may use the routes that take `files_caller`: list the
+folders and files, fetch a file and its hash, upload, delete — each only in a folder its token was
+granted that right in, and never the files shared with the user. A folder or file out of its reach
+answers like a missing one. Everything else here is the signed-in user's alone (`current_user`).
 """
 
 import base64
@@ -29,6 +34,7 @@ from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm import Session
 
 from app import audit, sysconfig
+from app.apitokens import FilesCaller, Right, files_caller
 from app.audit import AuditAction
 from app.auth import current_user
 from app.collation import collated
@@ -208,7 +214,7 @@ UPLOAD_FOLDER_HEADER = "x-upload-folder"
 @dataclass(frozen=True)
 class SpooledUpload:
     """What the body dependency hands the handler: the bytes already on disk and their hash, plus
-    the names and the folder that came alongside them."""
+    the names and the folder that came alongside them, and who sent them."""
 
     path: Path
     size: int
@@ -217,6 +223,7 @@ class SpooledUpload:
     filename: str
     display_name: str | None
     folder_id: int | None
+    via: str | None = None
 
 
 def _header_text(request: Request, name: str) -> str:
@@ -233,15 +240,21 @@ def _header_text(request: Request, name: str) -> str:
         return ""
 
 
-def _upload_folder(db: Session, user_id: int, raw: str) -> int | None:
+def _upload_folder(db: Session, caller: FilesCaller, raw: str) -> int | None:
     """The folder id an upload asked for (`UPLOAD_FOLDER_HEADER`), checked; None when it asked for
-    none."""
+    none — which a token may not: it writes only where it was granted to."""
     if not raw.strip():
+        if caller.grants is not None:
+            raise refused(400, "api_token_folder_required")
         return None
     try:
-        return folders.upload_target(db, user_id, int(raw), hold=False).id
+        folder_id = int(raw)
     except ValueError as e:
         raise refused(409, "file_folder_gone") from e
+    if not caller.may(folder_id, Right.WRITE):
+        raise not_found("folder")
+    try:
+        return folders.upload_target(db, caller.user.id, folder_id, hold=False).id
     except folders.FolderError as e:
         raise refused(409, e.reason) from e
 
@@ -260,24 +273,26 @@ class _HashingSink:
 
 async def spool_upload(
     request: Request,
-    user: User = Depends(current_user),
+    caller: FilesCaller = Depends(files_caller),
     db: Session = Depends(get_db),
 ) -> AsyncIterator[SpooledUpload]:
     """Stream the request body to a staging temp file, enforcing the per-file cap as it arrives.
 
-    `user` is taken but unused: it is the whole point. Dependencies resolve in declaration order, so
-    naming `current_user` here makes the auth check a precondition of reading the body at all — a
-    stranger is refused before a byte moves. The `yield` shape owns the temp file's life: ingest
-    MOVES it into place on success (the unlink is then a no-op), and on any other exit — cap hit,
-    empty, quota, probe or move error, a client that vanished mid-upload — it is removed."""
+    `caller` comes first on purpose. Dependencies resolve in declaration order, so naming
+    `files_caller` here makes the auth check a precondition of reading the body at all — a stranger,
+    or a token without the right to write in that folder, is refused before a byte moves. The
+    `yield` shape owns the temp file's life: ingest MOVES it into place on success (the unlink is
+    then a no-op), and on any other exit — cap hit, empty, quota, probe or move error, a client that
+    vanished mid-upload — it is removed."""
     cap = sysconfig.get_int(db, "download_upload_max_bytes")
-    user_id = user.id
+    user_id = caller.user.id
+    via = caller.via
     # A folder the file may not go in is refused before the transfer, not after it.
-    folder_id = _upload_folder(db, user_id, request.headers.get(UPLOAD_FOLDER_HEADER, ""))
+    folder_id = _upload_folder(db, caller, request.headers.get(UPLOAD_FOLDER_HEADER, ""))
     # Hand the pooled connection back BEFORE the transfer starts — see `db.release_read_connection`
     # for why, and for the precondition it enforces. Everything this dependency still needs is
-    # already an int or a header in hand: touching an ORM attribute below would reload `user` and
-    # check a connection straight back out.
+    # already an int, a string or a header in hand: touching an ORM attribute below (`caller.user`)
+    # would reload it and check a connection straight back out.
     release_read_connection(db)
     staging = Path(settings.files_root) / ".staging" / "uploads"
     staging.mkdir(parents=True, exist_ok=True)
@@ -300,6 +315,7 @@ async def spool_upload(
             filename=_header_text(request, UPLOAD_FILENAME_HEADER) or "upload",
             display_name=display_text(_header_text(request, UPLOAD_DISPLAY_NAME_HEADER)),
             folder_id=folder_id,
+            via=via,
         )
     finally:
         tmp_path.unlink(missing_ok=True)
@@ -322,6 +338,17 @@ def accessible_job(db: Session, user: User, job_id: int) -> DownloadJob:
     return job
 
 
+def readable_job(db: Session, caller: FilesCaller, job_id: int) -> DownloadJob:
+    """A file `caller` may read: as `accessible_job` for the user; for a token, one of the user's
+    own in a folder it may read."""
+    if caller.grants is None:
+        return accessible_job(db, caller.user, job_id)
+    job = db.get(DownloadJob, job_id)
+    if job is None or job.user_id != caller.user.id or not caller.may(job.folder_id, Right.READ):
+        raise not_found("download")
+    return job
+
+
 # --- folders -------------------------------------------------------------------------------
 
 
@@ -340,19 +367,24 @@ def _serialize_folder(folder: FileFolder, count: int, size: int) -> dict:
 
 
 @router.get("/folders")
-def list_folders(user: User = Depends(current_user), db: Session = Depends(get_db)) -> list[dict]:
-    """The caller's folders with how many files each holds and their size. A source folder its
-    files have all left stays (count 0): the client decides whether to show it."""
+def list_folders(
+    caller: FilesCaller = Depends(files_caller), db: Session = Depends(get_db)
+) -> list[dict]:
+    """The caller's folders with how many files each holds and their size (a token: the ones it may
+    list). A source folder its files have all left stays (count 0): the client decides whether to
+    show it."""
     done = (DownloadJob.folder_id == FileFolder.id) & (DownloadJob.status == JobStatus.DONE)
+    stmt = select(
+        FileFolder,
+        func.count(DownloadJob.id),
+        func.coalesce(func.sum(MediaAsset.size_bytes), 0),
+    ).where(FileFolder.user_id == caller.user.id)
+    listable = caller.folders_with(Right.LIST)
+    if listable is not None:
+        stmt = stmt.where(FileFolder.id.in_(listable))
     rows = db.execute(
-        select(
-            FileFolder,
-            func.count(DownloadJob.id),
-            func.coalesce(func.sum(MediaAsset.size_bytes), 0),
-        )
-        .outerjoin(DownloadJob, done)
+        stmt.outerjoin(DownloadJob, done)
         .outerjoin(MediaAsset, MediaAsset.id == DownloadJob.asset_id)
-        .where(FileFolder.user_id == user.id)
         .group_by(FileFolder.id)
         .order_by(FileFolder.kind.desc(), FileFolder.source_key, FileFolder.name, FileFolder.id)
     ).all()
@@ -520,12 +552,20 @@ def list_files(
     sort: Literal["added", "name", "size"] = "added",
     order: Literal["asc", "desc"] = "desc",
     scope: Literal["mine", "shared"] = "mine",
-    user: User = Depends(current_user),
+    caller: FilesCaller = Depends(files_caller),
     db: Session = Depends(get_db),
 ) -> list[dict]:
     """The caller's done files (`scope=mine`, optionally one folder's), or the ones shared with
     them (`scope=shared`); searched by name and channel, sorted by when they were added, by name
-    (in the reader's alphabet) or by size."""
+    (in the reader's alphabet) or by size. A token lists only in the folders it may list, and never
+    the shared ones."""
+    user = caller.user
+    listable = caller.folders_with(Right.LIST)
+    if listable is not None:
+        if scope == "shared":
+            raise refused(403, "api_token_scope")
+        if folder_id is not None and folder_id not in listable:
+            raise not_found("folder")
     stmt = (
         select(DownloadJob)
         .join(MediaAsset, MediaAsset.id == DownloadJob.asset_id)
@@ -540,6 +580,8 @@ def list_files(
         stmt = stmt.where(DownloadJob.user_id == user.id)
         if folder_id is not None:
             stmt = stmt.where(DownloadJob.folder_id == folder_id)
+        elif listable is not None:
+            stmt = stmt.where(DownloadJob.folder_id.in_(listable))
     name = func.coalesce(DownloadJob.display_name, MediaAsset.title, "")
     term = q.strip()
     if term:
@@ -693,11 +735,23 @@ def update_file(
 
 @router.delete("/{job_id}")
 def delete_file(
-    job_id: int, user: User = Depends(current_user), db: Session = Depends(get_db)
+    job_id: int, caller: FilesCaller = Depends(files_caller), db: Session = Depends(get_db)
 ) -> dict:
-    """Delete a file from the caller's library; the bytes go with their last holder."""
-    job = own_job_for_update(db, user, job_id)
-    audit.record(db, user.id, AuditAction.FILE_DELETE, target_type="file", target_id=job_id)
+    """Delete a file from the caller's library; the bytes go with their last holder. A token
+    deletes only in a folder it may delete in — judged on the row as locked, so a file moved out of
+    that folder meanwhile is out of its reach."""
+    job = own_job_for_update(db, caller.user, job_id)
+    if not caller.may(job.folder_id, Right.DELETE):
+        db.rollback()  # lets go of the locks; nothing was written
+        raise not_found("download")
+    audit.record(
+        db,
+        caller.user.id,
+        AuditAction.FILE_DELETE,
+        target_type="file",
+        target_id=job_id,
+        summary=caller.via,
+    )
     service.delete(db, job)  # commits, the audit row with it
     return {"ok": True, "deleted": job_id}
 
@@ -732,6 +786,7 @@ def ingest_spooled(db: Session, upload: SpooledUpload) -> DownloadJob:
             display_name=upload.display_name,
             sha256=upload.sha256,
             folder_id=upload.folder_id,
+            via=upload.via,
         )
     except quota.QuotaExceeded as e:
         raise HTTPException(status_code=422, detail=quota_detail(e)) from e
@@ -782,8 +837,10 @@ def serve_file(db: Session, job: DownloadJob) -> FileResponse:
 
 
 @router.get("/{job_id}/file")
-def get_file(job_id: int, user: User = Depends(current_user), db: Session = Depends(get_db)):
-    response = serve_file(db, accessible_job(db, user, job_id))
+def get_file(
+    job_id: int, caller: FilesCaller = Depends(files_caller), db: Session = Depends(get_db)
+):
+    response = serve_file(db, readable_job(db, caller, job_id))
     db.commit()
     return response
 
@@ -840,13 +897,13 @@ def preview_file(
 
 @router.get("/{job_id}/sha256")
 def get_sha256(
-    job_id: int, user: User = Depends(current_user), db: Session = Depends(get_db)
+    job_id: int, caller: FilesCaller = Depends(files_caller), db: Session = Depends(get_db)
 ) -> dict:
     """The file's SHA-256 (hex), hashed now if it never was and kept on the asset for every holder.
     A sync handler: hashing a large file is blocking disk work, so it runs in the threadpool — and
     every other sync route shares that pool, so only `_HASHERS` files are hashed at a time (a caller
     past that is told to come back), and none of them holds a database connection while it reads."""
-    asset, path = _ready_file(db, accessible_job(db, user, job_id))
+    asset, path = _ready_file(db, readable_job(db, caller, job_id))
     if asset.sha256:
         return {"sha256": asset.sha256}
     asset_id = asset.id

backend/app/routes/tokens.py

@@ -0,0 +1,177 @@
+"""A user's API tokens for their Files library (`app.apitokens`): list, make, revoke.
+
+Signed-in only — `current_user`, never a token: a token cannot make itself a wider one. A new
+token's value is in the answer that made it and nowhere after; only its hash is kept.
+
+The Hub preset is the one machine a user swaps files with: it makes (or reuses) their Hub folder
+and gives the token every right in it, so the hub both drops files there and picks up the ones put
+there for it.
+"""
+
+from datetime import datetime, timedelta, timezone
+from typing import Literal
+
+from fastapi import APIRouter, Depends
+from pydantic import BaseModel, Field
+from sqlalchemy import func, select
+from sqlalchemy.orm import Session
+
+from app import apitokens, audit
+from app.apitokens import GRANT_COLUMNS, Right
+from app.audit import AuditAction
+from app.auth import current_user
+from app.db import get_db
+from app.downloads import folders
+from app.models import ApiToken, ApiTokenGrant, FileFolder, User
+from app.refusal import refused
+from app.routes._common import owned_or_404
+from app.security import hash_token
+from app.utils import iso
+
+router = APIRouter(prefix="/api/tokens", tags=["tokens"])
+
+# Far more than one person's machines; a ceiling, so a script gone wrong cannot mint without end.
+MAX_TOKENS = 20
+_MAX_GRANTS = 50
+_MAX_EXPIRY_DAYS = 3650
+
+
+class GrantIn(BaseModel):
+    folder_id: int
+    rights: list[Right] = Field(min_length=1, max_length=len(Right))
+
+
+class TokenIn(BaseModel):
+    name: str = Field(min_length=1, max_length=80)
+    # None = never expires.
+    expires_days: int | None = Field(default=None, ge=1, le=_MAX_EXPIRY_DAYS)
+    preset: Literal["hub"] | None = None
+    grants: list[GrantIn] = Field(default_factory=list, max_length=_MAX_GRANTS)
+
+
+def _serialize(db: Session, token: ApiToken) -> dict:
+    rows = db.execute(
+        select(ApiTokenGrant, FileFolder)
+        .join(FileFolder, FileFolder.id == ApiTokenGrant.folder_id)
+        .where(ApiTokenGrant.token_id == token.id)
+        .order_by(FileFolder.id)
+    ).all()
+    now = datetime.now(timezone.utc)
+    return {
+        "id": token.id,
+        "name": token.name,
+        "prefix": token.prefix,
+        "created_at": iso(token.created_at),
+        "expires_at": iso(token.expires_at),
+        "expired": token.expires_at is not None and token.expires_at <= now,
+        "last_used_at": iso(token.last_used_at),
+        "grants": [
+            {
+                "folder_id": folder.id,
+                "kind": folder.kind,
+                "source_key": folder.source_key,
+                "name": folder.name,
+                "rights": sorted(apitokens.grant_rights(grant)),
+            }
+            for grant, folder in rows
+        ],
+    }
+
+
+@router.get("")
+def list_tokens(user: User = Depends(current_user), db: Session = Depends(get_db)) -> list[dict]:
+    tokens = (
+        db.execute(select(ApiToken).where(ApiToken.user_id == user.id).order_by(ApiToken.id))
+        .scalars()
+        .all()
+    )
+    return [_serialize(db, t) for t in tokens]
+
+
+def _wanted_grants(db: Session, user: User, body: TokenIn) -> dict[int, set[Right]]:
+    """Folder id → the rights the new token gets there; every folder checked to be the user's, and
+    writing only where an upload may land (`folders.upload_target`)."""
+    if body.preset == "hub":
+        if body.grants:
+            raise refused(400, "api_token_preset_grants")
+        return {folders.hub_folder(db, user.id).id: set(Right)}
+    if not body.grants:
+        raise refused(400, "api_token_no_grants")
+    wanted: dict[int, set[Right]] = {}
+    for grant in body.grants:
+        wanted.setdefault(grant.folder_id, set()).update(grant.rights)
+    for folder_id, rights in wanted.items():
+        try:
+            if Right.WRITE in rights:
+                folders.upload_target(db, user.id, folder_id, hold=False)
+            else:
+                folders.own_folder(db, user.id, folder_id, hold=False)
+        except folders.FolderError as e:
+            raise refused(409, e.reason) from e
+    return wanted
+
+
+@router.post("")
+def create_token(
+    body: TokenIn, user: User = Depends(current_user), db: Session = Depends(get_db)
+) -> dict:
+    """Make a token; its value is in this answer only."""
+    name = body.name.strip()
+    if not name:
+        raise refused(400, "api_token_name_required")
+    # The user's row, locked: two requests at once cannot both slip under the ceiling.
+    db.execute(select(User.id).where(User.id == user.id).with_for_update())
+    count = db.execute(
+        select(func.count(ApiToken.id)).where(ApiToken.user_id == user.id)
+    ).scalar_one()
+    if count >= MAX_TOKENS:
+        raise refused(409, "api_token_limit", limit=MAX_TOKENS)
+    wanted = _wanted_grants(db, user, body)
+    raw = apitokens.mint()
+    token = ApiToken(
+        user_id=user.id,
+        name=name,
+        prefix=raw[: apitokens.SHOWN_LEN],
+        token_hash=hash_token(raw),
+        expires_at=None
+        if body.expires_days is None
+        else datetime.now(timezone.utc) + timedelta(days=body.expires_days),
+    )
+    db.add(token)
+    db.flush()
+    for folder_id, rights in wanted.items():
+        db.add(
+            ApiTokenGrant(
+                token_id=token.id,
+                folder_id=folder_id,
+                **{col: right in rights for right, col in GRANT_COLUMNS.items()},
+            )
+        )
+    db.flush()
+    audit.record(
+        db,
+        user.id,
+        AuditAction.API_TOKEN_CREATE,
+        target_type="api_token",
+        target_id=token.id,
+        after={
+            "grants": {str(f): sorted(r) for f, r in wanted.items()},
+            "expires_at": iso(token.expires_at),
+        },
+    )
+    db.commit()
+    return {"ok": True, **_serialize(db, token), "token": raw}
+
+
+@router.delete("/{token_id}")
+def revoke_token(
+    token_id: int, user: User = Depends(current_user), db: Session = Depends(get_db)
+) -> dict:
+    """Revoke a token: it stops working at its next request (its grants go with it)."""
+    token = owned_or_404(db, ApiToken, token_id, user, what="api_token")
+    db.delete(token)
+    audit.record(
+        db, user.id, AuditAction.API_TOKEN_REVOKE, target_type="api_token", target_id=token_id
+    )
+    db.commit()
+    return {"ok": True, "deleted": token_id}