Commit Graph
2 Commits
Author SHA1 Message Date
jaap-jan 5fccd53824 Add the Avalonia app and the xterm renderer, and fix two real bugs
The terminal works end to end. A new integration test drives a real sshd in
a container through a real PTY, the real pump, the real loopback WebSocket
with its token and origin checks, and a ClientWebSocket standing in for the
page: the login banner arrives, typed input round-trips, and `stty size`
reports the 100x30 the session asked for. The only untested link left is
xterm drawing bytes it was handed.

The WebView is de-risked on Windows, which was the plan's largest risk. Not
by assertion: with the app running there is an established TCP connection
from msedgewebview2 to the data plane port, so WebView2 launched, navigated
to the loopback page, executed terminal.js, and completed the WebSocket
handshake against the real token and origin checks. Linux remains unproven
and the package's own release notes now corroborate the concern -- Linux uses
a WPE backend, and it ships a NativeWebDialog described as useful where
embedded WebViews may be unavailable.

Two bugs found by building it, both of which would have shipped:

- ShellStream.Write buffers and needs an explicit Flush. Without one a
  keystroke is accepted, reported as written, and never reaches the remote:
  the terminal displays output perfectly and simply stops responding to
  input. SSH.NET's own WriteLine flushes, which is why the earlier spike
  never hit it. Found by isolating the pump against real SSH and reading
  BytesRead=51 -- banner and prompt through, nothing after.
- The Windows app manifest needs a supportedOS list, or Avalonia's native
  control host fails outright and the terminal never starts.

Also fixed a genuinely flaky test I happened to catch: SyncCursorTests
tampered with the *last* base64url character, whose low bits the decoder
ignores when the input length is not a multiple of three -- so a tampered
cursor sometimes decoded to identical bytes and verified. It failed roughly
one run in thirty, depending on a random key. Now tampers the penultimate
character, which is fully significant at every length; 40 consecutive runs
are clean.

xterm 6.0.0 plus the fit and webgl addons are vendored as UMD bundles rather
than built with npm, so a clean clone needs only the .NET SDK. Provenance
and licences are recorded next to them, along with the UMD global names
terminal.js depends on -- a bundle that switched to ES modules would load
without error and leave Terminal undefined.

The renderer acknowledges output from term.write's completion callback, not
on receipt. Acknowledging early would return flow-control credit for bytes
the screen has not caught up with, which is the one thing the credit window
exists to measure.

TerminalWorkspace moved into DodoSSH.Client.Terminal: it has no Avalonia
dependency, and having it there is what let the end-to-end test exist at all.

404 tests pass, zero warnings on a clean rebuild, format clean.
2026-07-28 22:30:42 +02:00
jaap-jan 885fb17bdc Clear the SSH gate: window-change reaches the remote, and licence as MIT
Licence is MIT, set solution-wide rather than only on the packable project:
DodoSSH.Contracts is published so clients can build against it, and a
package with no licence expression is one a corporate policy scanner
rejects outright.

The SSH.NET spike is the M1 client gate and it passes. SSH.NET 2025.1.0
exposes ShellStream.ChangeWindowSize, but a method existing is not the
remote observing it, so the tests read `stty size` back from a real sshd
after resizing rather than asserting the call did not throw. Repeated
resizes each take effect too, which matters because dragging a window edge
produces a stream of them. The IChannelSession fallback is not needed.

Also verified against a real sshd: password and public-key auth, that the
host key arrives as a raw blob we can fingerprint ourselves rather than
reading SSH.NET's MD5 property, and that refusing the key via CanTrust
actually aborts the connection -- without which the TOFU dialog would be
decoration.

Kept as a permanent suite, not deleted after the spike. An upgrade that
silently stopped sending the request would present as wrapped output only
after a resize, which is easy to misattribute to the terminal emulator.

Two bugs in the test itself, both worth naming because either would have
been read as "resize does not work":

- A PTY emits CRLF, and the anchored regex rejected the CR. The output
  visibly contained `24 80` while the match failed.
- Each read can begin with output still buffered from the previous command,
  including its size line. Taking the first match would have reported the
  pre-resize size.

platform-flags.md now records window-change as resolved rather than
unverified -- a stale flag is worse than none -- plus the three real SSH.NET
limits found on the way: ShellStream does not override ReadAsync so every
idle session parks a pool thread, one connection cannot serve both
SshClient and SftpClient, and agent forwarding needs an upstream change.
2026-07-28 16:52:09 +02:00