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 3829217e8a Add sync engine: cursors, push/pull, and the advisory-lock ordering proof (M1)
The vault write path. Push is the only way items change — no per-entity POST/PUT/DELETE —
so one place enforces revisions, the change log and access control.

The concurrency hazard, now proven rather than asserted:
bigserial assigns sequence values when the INSERT runs, not at commit, so transaction A
can take sequence 5 while B takes 6 and commits first. A reader polling in between sees
only 6, advances past 5, and never learns about it. AdvisoryLockOrderingTests reproduces
that gap WITHOUT the lock first — otherwise the with-lock test proves nothing, since it
would pass just as happily if the interleaving never occurred — then shows
pg_advisory_xact_lock removes it, and that 12 concurrent writers produce no gaps.

Cursors are opaque and HMAC-tagged, and carry their vault id. 29 unit tests cover the
rejections, which are the point: an accepted-but-wrong cursor is silent data loss, strictly
worse than an error a client can resync from. Rejected: tampered tag, tampered payload,
foreign signing key, a legitimately-issued cursor from another vault, truncation, and
hostile input (never throws — cursors come from clients).

Push semantics:
- 200 even on partial failure, with per-operation status, so one stale item cannot block
  everything a client queued while offline.
- Conflict returns the server's current row for client-side three-way merge. The server
  cannot merge ciphertext, so never last-writer-wins.
- opId receipts make retries exactly-once per operation, not per batch — a client retrying
  a partially-overlapping batch after a timeout would otherwise double-apply what landed.
- A tombstone beats a late upsert, and delete clears hostname/port: leaving the address
  would keep the server able to resolve a host the user believes they deleted.
- Relay field validation mirrors the DB CHECK so a bad request is a clear Invalid rather
  than a constraint violation surfacing as a 500.

Authorization goes through IVaultAccessService, which returns the same answer for "absent"
and "forbidden" — distinguishing them is an existence oracle for other tenants' vault ids.
Team vaults are explicitly denied until M3 rather than falling through to a permissive
default. JIT provisioning keys on (issuer, subject), never email, and handles the
concurrent-first-request race via the unique index.

Renamed two domain types: Host -> SshHost, because Host collides with
Microsoft.Extensions.Hosting.Host in every file of a web project, and SyncChange ->
VaultChange to stop it colliding with the Contracts DTO of the same name. Aliasing at every
use site would have been permanent friction.

Worth noting: `ef migrations has-pending-model-changes` reported clean after those renames
even though the snapshot still said "DodoSSH.Domain.Host" — it diffs tables, not CLR type
names. The snapshot was regenerated and the emitted DDL diffed against the previous
artifacts/schema/v0.1.sql to confirm the rename produced no schema change.

Also removed ConfigureAwait(false) from test methods: xUnit1030 flags it as bypassing
parallelization limits, which is why MA0004 is suppressed in test projects.

Verified: 0 warnings on a clean rebuild, 146 tests pass (up from 122), format clean.

Endpoint-level tests are the immediate next step: they need a WireMock OIDC/JWKS stub and
real JWT minting, so the "wrong user is denied" matrix does not exist yet for these two
routes. The service-layer authorization and the concurrency property are covered.
2026-07-28 15:02:02 +02:00