dsh-session-sync

LAN session sync for DSH. Every DSH that has this plugin discovers the others on the local network, lists their sessions, and can pull or push conversations over plain HTTP. The nickname you give a device lives only on your machine — the peer can go offline, reboot, or change IP and come back, and you still see the name you gave it.

✨ Features

Three UI promises

• “This device” is always the first row, and one IP is never two devices. The card shows this machine's name, LAN address:sync port and running version. Any peer whose address belongs to this host is grouped underneath it as “other DSH instances on this machine” (browsable and pushable, so cross-profile sync still works) instead of counting as a device — the list and its counters only ever mean other machines.
• Untitled sessions carry #first-8-chars-of-session-id. A pile of “Untitled” rows looks identical; the id is what tells them apart. The pull plan's “already present” flag is keyed by the same peer + session id, so renaming a session never turns a duplicate into a fresh copy.
• A crashing UI is never blank. Render errors hit an error boundary that prints platform, Node version, host version, ports, UA and a stack summary, with Reload / Copy diagnostics. If Windows still shows nothing, paste that block into an issue.

🚀 Installation

dsh plugin --profile web add github:XXGxiaoyu/dsh-session-sync

Requires DSH 0.2.1-rc.2 (the version bundled with the current desktop app) and Node 22+.

Then restart the DSH desktop app (host-side changes load at boot; open pages pick up the new UI on refresh). The page footer shows the build that is actually running — if it reads an older number than the latest release, the process has not been restarted yet. The install is auto-activated: the package declares dsh.bundle, so dsh plugin add adds it to dsh.profile.bundles on its own.

Prebuilt tarball (no build step): https://github.com/XXGxiaoyu/dsh-session-sync/releases/latest/download/dsh-session-sync.tgz

// ~/.dsh/profiles/<profile>/package.json
{
  "dependencies": {
    "dsh-session-sync": "link:/absolute/path/to/dsh-session-sync"
  },
  "dsh": {
    "profile": {
      "bundles": ["@deepseek-ai/dsh-base", "@deepseek-ai/dsh-web-app", "dsh-session-sync"]
    }
  }
}

cd ~/.dsh/profiles/<profile> && pnpm install

Confirm it loaded — the log shows:

[dsh-session-sync] ready: device <hostname>, sync port 47802, discovery port 47801
[dsh-session-sync] discovered <peer name> (192.168.1.7:47802)

🧭 Where it lives

A Session Sync row appears under Plugins in the left sidebar (sidebar.panellist + keyed main panel, id session-sync). The same component is also registered as Settings → Session Sync (settings.section).

• This machine — the name other devices see; changing it broadcasts immediately.
• Devices — online/offline, last heartbeat, session count, platform and version.
• Rename / Forget — a per-device nickname for this machine only. Offline devices keep their row (and their nickname), greyed out.
• Sessions / Pull / Push — list a peer's sessions, copy one here, or send one over.
• Verify — re-fetch the peer's payload, recompute SHA-256 and compare it with the local copy (sha256 2b12f7854d80… verified).
• Integrity, not identity. A digest proves the bytes match; it does not prove who sent them — anyone can recompute it. So verification stays automatic and fail-closed, and there is no per-transfer “confirm the hash” prompt (that only trains people to click through). When you genuinely need authenticity, copy the full digest and compare it out-of-band (phone, terminal); the copy action sits next to the verified row.
• Sync settings — UI language, auto-pull, and manual peer addresses for networks where broadcast is blocked (ip or ip:udpPort, one per line).

🌏 UI language

settings.locale = 'auto' | 'zh' | 'en'   // persisted in <home>/session-sync/state.json

The plugin reads ctx.locale.getSnapshot().active (zh* → Chinese, everything else → English) and only falls back to navigator.languages when no locale service exists. A language change is written to disk before the UI switches, so it never reverts on the next open. Sidebar/settings labels are resolved by the host, so the plugin re-registers its slots when the language changes — the page and the sidebar row never disagree.

🎨 Look and motion

The UI uses DSH's own CSS variables rather than copied hex values: --dsw-alias-* for colors, --dsw-radius-*, the --dsw-font-* scale, and var(--ds-transition-duration) var(--ds-ease-in-out) for every transition. Layout follows the built-in settings pages — title + muted note on the left, control on the right, .5px dividers, 32px inputs/selects, 36×22 pill switches — so it stays consistent in both themes and in narrow windows.

⚙️ Configuration (loader row config)

🔌 LAN protocol (/v1/*)

Binds 0.0.0.0; every route except /v1/health requires x-dsh-session-sync: 1.

Discovery is a UDP broadcast: every 4s a dsh-session-sync/hello datagram ({id, name, port, platform, version, sessions}) goes to each IPv4 interface's broadcast address, 127.0.0.1, and any configured seeds; unknown ids are answered by unicast right away.

The GUI side (/session-sync/api) runs on DSH's own loopback web server and is fenced by the host connection policy; /v1/* is the only surface exposed to the LAN.

🧵 Design notes

• Nicknames are keyed by device id, not IP. deviceId is a uuid generated on first start; peers[<deviceId>].customName is yours alone.
• Imports use the official persistence service — ctx.sessionPersistence.create() → append() → flush(), with a v4 header that keeps only the allowed keys (version/id/createdAt/cwd/isSeeded/delegationDepth/parentSession/agentPreset). One extra type is rejected with format v4 header has unexpected field type.
• Imports keep the source createdAt, re-index ids and seq. The id must be unique per machine; seq starts at 0 and stays contiguous; createdAt is preserved so content fingerprints agree.
• Cross-machine cwd. The source cwd is kept when it exists here, otherwise it falls back to process.cwd() — a session pointing at a path that does not exist would vanish from the workspace list.
• SHA-256 is byte-exact. Exports and imports serialize the same object, so key order is identical and digests are comparable. Mismatch aborts before persistence.
• Your own machine is not a device. The device list only ever holds other machines: peers on this host's address are dropped on arrival (and pruned from history on boot), and several peers on one IP collapse into the freshest row. Rename this machine in the 本机 section; the counter only means other machines.
• Fingerprints, not ids, dedupe auto-pull. state.signatures[sha1(createdAt, event shape, first preview)] is recorded on export and import; auto-pull skips anything already known. Without it, two auto-pulling machines would keep re-importing the same conversation under new ids.
• Everything local stays local. Nicknames, import records and settings never leave <home>/session-sync/state.json.

🧪 Development

node --test --test-force-exit --test-timeout=120000 'test/*.test.mjs'

35 cases: client bundle contract, dictionary parity, footer, stale-host hint and version pinning (13), jsdom mount and interactions (5), two-instance end-to-end — discovery, rename persistence, restart, pull/push, auto-pull dedupe, receiver dedupe, SHA-256 tamper rejection and HTTP-only discovery (8), and the probe fallback contract (7).

Run a headless instance without the desktop shell:

DSH_HOME=/tmp/dsh-ss-home node <dsh>/lib/bin.js --profile ssync --no-open --host 127.0.0.1 --port 4399

--profile must come before launcher flags such as --no-open; web --profile x fails with select a profile only once.

📄 License

MIT