Commit Graph
3 Commits
Author SHA1 Message Date
jaap-jan 04faef6597 Move files to and from a host over SFTP
M2's file transfer, built bottom-up: an SFTP session on the SSH layer, a
transfer queue in a project of its own, and the two-pane browser the design
asked for replacing the screen that said it did not exist. Remote listings
carry names, sizes, modification times and a real drwxr-xr-x — nothing in this
repository could render a POSIX mode before — and the queue moves one file at a
time with progress, throughput and resume.

The design import assumed this would be an SFTP subsystem channel on
ISshConnection, beside the shell on a transport that is already up. SSH.NET
does not offer that: SftpClient derives from BaseClient and owns its own
transport, and there is no supported way to hand it an SshClient's session. So
file transfer opens a second authenticated connection, and it is named for
that rather than dressed up as a channel — OpenSftpAsync is on
ISftpSessionFactory, not on a connection. The difference is visible to a user:
the host records a second login, and a host whose password is typed each time
asks for it again on this screen. It goes through the same host key gate, the
same pin and the same two refusals a shell does, so a fingerprint approved for
a terminal is approved here and one approved here reaches the other machines
with the next sync. docs/design-import-gaps.md is corrected, and marked as the
one row where what shipped differs from what it predicted.

Nothing is written at its final name until it is complete. Every transfer goes
to a .dodossh-part file beside its destination and is renamed into place at the
end, so an interrupted transfer can never be mistaken for a finished one —
which matters most for what this screen is actually for, which is copying a
build artefact onto a server and then running it. A destination that already
exists is refused outright rather than overwritten: the queue has no way to
ask, and silently replacing a file somebody's process is serving is the worse
of the two failures. The remote pane has DELETE and MKDIR so that refusal is
not a dead end. A test against the container pins the assumption underneath all
of this — that SFTP's rename does not clobber.

Resume works within a run of the application and not across a restart, and the
limit is deliberate rather than unfinished. Nothing records which source wrote
a part file, and resuming one on the strength of its name matching is how a
corrupt artefact gets delivered with nothing reporting a failure; a part file
found at startup is started over. Making it survive a restart needs the
preferences store this client still has not got. The offset a resume starts at
is the part file's own length rather than the transfer's recorded progress: a
cancellation can land between a write completing and the counter moving, and
only one of those two is a fact about the bytes that are there.

The queue and its connection outlive a lock, as shells do. LockAsync already
argues that locking must not destroy work in flight — it is what somebody does
when they walk away from the machine, which is exactly when a long transfer is
most likely to be running — so TransfersViewModel is created once and the vault
is attached on unlock and detached on lock. What locking takes is the host
list, and it has to: those rows carry decrypted secrets.

DodoSSH.Client.Transfer is a new project rather than more of Client.Ssh. The
two answer different questions — one is about reaching a host, the other about
moving bytes and what to do when moving them stops halfway — and this is the
only client project that deliberately touches the local filesystem.

Three defects the tests found, none of which review would have. SftpPath.Name
answered an empty string for the root. NavigateRemoteAsync wrapped itself in
the busy guard, so navigating from inside another command did nothing at all
and the remote pane simply stayed empty after connecting, with no failure
anywhere to explain it. And opening an SFTP session per test made two
handshakes per test — this client learns a host key by being refused — which
pushed the SSH assembly past sshd's MaxStartups and failed a different few
unrelated tests each run; the session is shared through the fixture now, with
the reason written where the next person will hit it.

1004 tests green across 18 projects, 24 of them new: the SFTP subsystem against
the OpenSSH container, the queue against a real temporary directory and a fake
host, and three more layout measurements because a screen this window has never
laid out is a screen never checked.

Not verified: the screen has not been looked at running. The layout harness
measures it at the window's minimum in three shapes, which is the class of
defect that has shipped here before, but reaching it in the application needs
the compose stack, the migrations, the API and a browser sign-in. What is still
absent — the status bar's transfer count, dragging between the panes,
transferring a directory, and sftp over a bastion — is in
docs/design-import-gaps.md.
2026-07-31 11:07:29 +02:00
jaap-jan 94e11f5e38 update packages
ci / build and test (ubuntu) (push) Canceled after 0s
ci / build (windows) (push) Canceled after 0s
2026-07-31 10:12:05 +02:00
jaap-jan c5dec2d68e Measure the vault column instead of arguing about it
Nothing in this repository loaded a .axaml, so the one class of defect this
window has actually shipped — a control arranged past the edge of its container,
where it cannot be clicked — was the one class nothing could catch. The setup
screens rendered sliced once, with their buttons unreachable. The vault column is
the next candidate: 340 pixels wide, two lists and two editors, and the only
thing keeping it from clipping its own Save button at the window's 520-pixel
minimum is a state rule that one editor may be open at a time.

That rule was added on the strength of an argument. This adds an
Avalonia.Headless project that lays real XAML out at a real size and reports
what a user could not reach, and the argument is now a number: with both editors
open the column overflows, so the rule is load-bearing rather than defensive.
BothEditorsAtOnce_DoNotFit_WhichIsWhyTheRuleExists is the test, and it says what
to do if it ever starts passing — the column has room, so delete the rule, not
the test.

Two findings arrived by measuring rather than by reasoning, and the first one
changed the design.

MainWindow cannot be shown headlessly at all. Showing it attaches the terminal's
NativeWebView, whose Win32 adapter initialises WebView2 on attach, and WebView2
refuses a non-STA thread — which is exactly why Program.Main carries [STAThread]
and is written down in that comment. A HeadlessUnitTestSession owns its
dispatcher thread and offers no apartment choice, so the whole window is out of
reach at any size. That is pinned as a test asserting RPC_E_CHANGED_MODE by
HResult rather than by message, so a future Avalonia that makes the adapter lazy
will fail it and the harness can be widened.

So the column had to become its own control to be measurable, which is the
extraction the type-selector rework wanted anyway. Keyboard release moved with
it: MainWindow used to call Focus() on HostList by name, and now asks
VaultColumn.KeyboardTarget. The window decides that the keyboard should leave the
terminal and the column decides where it lands — which is the seam the rework
needs, because once the column shows one list at a time, "which list owns the
keyboard" is a question only the column can answer.

The second finding is the way this kind of test lies quietly. The hint class
lived in MainWindow.Styles and carries TextWrapping. A Window's styles reach its
whole tree, so nothing about the application depended on where it lived — but a
control laid out on its own loses them, and every hint paragraph would have
measured as a single line. The harness would have passed while measuring heights
that were all too small. The three shared classes now live in App.axaml, which
changes no rendering and makes the measurement honest.

The detector is calibrated in both directions, because a clipping detector that
never fires reads as a guarantee: a deliberately clipped Save button is caught by
name, and a list longer than its viewport is exempt. Scrolling is how a list is
supposed to handle more rows than fit, and without that exemption the host list
would fail the moment it had content. It also mis-fired once and the rule is
narrower for it — an empty ListBox is zero pixels tall and correct, so "arranged
with no size" now applies only to controls the theme gives a height to.

Skia rather than the headless drawing stub, deliberately. The stub's font manager
invents glyph metrics, and text height is an input to every stacked panel in this
column, so measuring against it would produce numbers that are self-consistent
and unrelated to the application.

A separate test project rather than more tests in DodoSSH.Client.App.Tests.
Avalonia's application, dispatcher and platform are process-global singletons
initialised once, and that project's identity is the shell's state machine
without Avalonia — the whole reason sign-in is a delegate. The fakes needed to
reach a real unlocked vault are shared from DodoSSH.Client.Session.Tests by
source link: a project reference would make one test project a library of
another, and a copy would be a third implementation of the same decision table
drifting from the other two.

855 tests green, 10 of them new. Zero warnings, dotnet format clean.

Not done, and this is groundwork rather than the item itself: the type selector.
The column still holds both lists at once, so a third item type would still
recreate the defect the one-editor rule works around. What is different is that
the rework can now be checked instead of eyeballed — including the claim it is
being made for, that one editor at a time stops being a runtime rule and becomes
a fact about what is in the visual tree.

What this harness will never catch is the terminal's native child window
compositing over Avalonia content. That is a Win32 property of a real window, no
headless surface reproduces it, and it is the reason the WebView is collapsed
rather than covered.
2026-07-30 11:34:09 +02:00