description	kind
Browser-host wire layer for the web GUI: Remote RPC, event-stream delivery with reconnect, exact Fetch routes, the /api HTTP bridge, and the browser-trust fence.	package-reference

@deepseek-ai/dsh-client-connection

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Summary

The package carries browser-to-Host Remote calls, exact Fetch responses, and connection generations. The Client plugin mounts ctx.connection with current-page loopback state, a generic RPC carrier, the active generation and its Host facts, and the registration point for one generation source. A generation becomes visible when its source reports ready; source completion, failure, withdrawal, or an explicit stop clears it before ConnectionController reconnects with backoff.

Use this package
Browser authentication and request trust
Connection generation
Model Experience
Known Limitations and Deferred Work
Dev Note

Use this package

The browser uses HTTP POST for Remote unary calls. API Gateway owns the /api/remote.mux WebSocket and its logical streams; in-process compositions provide equivalent Remote streams through connection.rpc.open without opening a WebSocket. The Host half owns the sole /api route, Fetch bridge, browser authentication, Host/Origin checks, and exact GET/HEAD route registry. Typert Gateway claims generated Remote endpoints, feature packages register non-JSON responses such as Session-log downloads, and unclaimed requests return 404. Loopback hostname classification remains package-internal to the browser-facing Client state.

Browser authentication and request trust

Every Host RPC method and WebSocket stream requires one browser session; there is no method-specific loopback tier. Each process mints a random launch token. dsh-web-app prints and opens the ordinary root URL with ?token=...; frontend-static delegates root and index requests to ctx.connection.authorizeIndex, which accepts that token only on GET /, writes an authority-bound signed cookie, and redirects to clean /. A missing, expired, malformed, or wrong-authority cookie returns 401 before RPC dispatch. Static assets remain public. The HTTP carrier accepts no query token outside the root exchange and no Authorization-header token.

The cookie signing secret is the owner-scoped client-connection/browser-session grant record in ctx.credentials. The local provider persists it in $DSH_HOME/.credentials.yaml; BrowserAuth loads or creates the record during Connection activation and retains the secret in memory, so request authentication is synchronous. Deleting or replacing the record takes effect on the next Connection activation. Cookies carry an absolute issue/expiry interval, defaulting to 30 days through cookieMaxAgeDays, and bind the normalized hostname plus port in both their deterministic name and signed payload. They are host-only, Path=/, HttpOnly, and SameSite=Strict; they deliberately omit Secure because the shipped server uses loopback HTTP.

Before authentication, every request still passes src/api-request-trust.ts. Its Host must be loopback or match a trustedHosts entry: exact on host:port, any port on port-less entries, both sides WHATWG-normalized. An attached Origin must equal that Host and sec-fetch-site: cross-site is refused. Malformed configured authorities fail plugin load. These checks defend DNS rebinding and cross-site browser requests; they never establish identity. A failed Host/Origin check returns 403, while a trusted but unauthenticated request returns 401. dsh web --host 0.0.0.0 remains unsupported. Decision records: browser request trust and browser token authentication.

Connection generation

API Gateway Client registers the internal $events logical stream as the sole generation source, independently of whether any $on listener exists. The Host attaches all incremental listeners in the API Remotes source factory, then sends one { type: 'ready', clientId, host: { home } } item before events. ConnectionController publishes that generation and calls onConnected only after the ready item arrives, so baseline acquisition cannot race ahead of incremental observation.

An ended $events stream, a Remote stream error, a non-ready opening item, or a malformed event item invalidates the current generation. The controller immediately withdraws the generation, publishes reconnecting, and reopens $events after backoff. Gateway mux reconnects the physical WebSocket; Connection generation reopens the logical stream and establishes the next baseline starting point.

Model Experience

None, as the wire consumer layer moves already-composed messages between browser and host; nothing here reaches a model request.

KV Cache effect

None; this package neither assembles nor sends a provider request.

Known Limitations and Deferred Work

The /api bridge buffers each request body in memory — maxRequestBodyBytes (default 300 MiB, sized for the default 200 MiB aggregate image limit after base64 expansion plus envelope headroom) is therefore also the per-request resident bound; a streaming body path would be needed to lower it without shrinking the image limits.
The browser cookie is not marked Secure — loopback HTTP is the shipped transport, so exposing the same authority over plaintext networking can expose the bearer cookie in transit.
There is no logout operation — clearing the browser cookie ends one browser session; deleting the owner credential record and restarting dsh revokes every session.

Dev Note

Working context for maintainers — click to expand

None.

README.md