glm-5.2
3327d585da
OQ-40 resolved: alknet-http owns a shared reqwest_middleware::ClientWithMiddleware (not a bare reqwest::Client) with a two-layer middleware stack — RetryTransientMiddleware (reqwest-retry, exponential backoff on transient failures) + inlined RetryAfterMiddleware (from melotic/reqwest-retry-after, MIT, ~50 lines, inlined to bound the upstream's unbounded HashMap storage). The two are complementary: reqwest-retry's default strategy does not honor Retry-After. Hot-reload is rebuild-and-swap via ArcSwap (same pattern as ConfigIdentityProvider, ADR-035); a rebuild drops the connection pool, which is acceptable since a config change wanting a fresh pool is the trigger. The three one-way constraints stand unchanged: alknet-http owns its client (no env-var config, no shared global), credentials inject per-request from OperationContext.capabilities, outbound TLS uses the system trust store. Records the downstream layering boundary: the agent crate's provider SSE normalization (the solid part of aisdk's pattern — Vercel-UI-message normalization) sits on top of this client, consuming the reqwest::Response stream; it does not replace the client. The aisdk core/client.rs reference for client construction is dropped (env-var config + hand-rolled retry are the anti-patterns discarded); the from_openapi.ts SSE normalization reference in the forwarding-handler section is kept (separate, solid pattern). No ADR — the decision is internal to alknet-http: the client type does not cross crate boundaries (alknet-call never sees reqwest), the library choice is reversible, and it does not touch the system's structure, constraints, or cross-crate API surface. Updates: http-adapters.md (HTTP client section rewritten, references updated, constraints/OQ bullets updated), http-mcp.md (OQ-40 status flip), open- questions.md (OQ-40 resolved with full config-shape table), README.md (OQ-40 folded into the existing two-way-doors bucket), and three secondary docs (crates/http/README.md, overview.md, http-server.md) that carried stale 'open' OQ-40 references.
135 lines
10 KiB
Markdown
135 lines
10 KiB
Markdown
---
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status: draft
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last_updated: 2026-06-30
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---
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# alknet-http
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HTTP interface for alknet: serves HTTP/1.1 and HTTP/2 on standard ALPNs
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(with WebSocket upgrade for browser bidirectional access to the call
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protocol), and hosts the HTTP-backed call-protocol adapters
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(`from_openapi`, `to_openapi`, `from_mcp`, `to_mcp`). HTTP/3 + WebTransport
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(`h3`) is deferred per
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[ADR-044](../../decisions/044-defer-webtransport-browsers-use-websocket.md).
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## Documents
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| Document | Status | Description |
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|----------|--------|-------------|
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| [overview.md](overview.md) | draft | Crate purpose, two roles (server + client host), dependencies, adapter location map |
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| [http-server.md](http-server.md) | draft | `HttpAdapter` (`ProtocolHandler` for `h2`/`http/1.1` + WS upgrade), axum over QUIC, Bearer auth, stealth, `/healthz`, WebSocket browser path |
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| [http-adapters.md](http-adapters.md) | draft | `from_openapi` (reqwest client) and `to_openapi` (OpenAPI projection); no-env-vars invariant point |
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| [http-mcp.md](http-mcp.md) | draft | `from_mcp` / `to_mcp` (feature-gated), streamable-HTTP-only, stdio exclusion |
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| [webtransport.md](webtransport.md) | deferred | `h3`/WebTransport handler — **deferred per ADR-044**; spec kept intact for revival |
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## Applicable ADRs
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| ADR | Title | Relevance |
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|-----|-------|-----------|
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| [001](../../decisions/001-alpn-protocol-dispatch.md) | ALPN-Based Protocol Dispatch | `HttpAdapter` registers on standard HTTP ALPNs |
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| [002](../../decisions/002-protocol-handler-trait.md) | ProtocolHandler Trait | `HttpAdapter` implements `ProtocolHandler` |
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| [003](../../decisions/003-crate-decomposition.md) | Crate Decomposition | `alknet-http` depends on `alknet-core` + `alknet-call` (protocol-foundation exception, Amendment 1) |
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| [004](../../decisions/004-auth-as-shared-core.md) | Auth as Shared Core | Bearer → `resolve_from_token` |
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| [007](../../decisions/007-bistream-type-definition.md) | BiStream Type Definition | `HttpAdapter` receives `Connection`, accepts a stream for hyper |
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| [010](../../decisions/010-alpn-router-and-endpoint.md) | ALPN Router and Endpoint | Stealth mode = HTTP handler on standard ALPNs |
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| [014](../../decisions/014-secret-material-flow-and-capability-injection.md) | Secret Material Flow | `from_openapi`/`from_mcp` are the credential injection point |
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| [015](../../decisions/015-privilege-model-and-authority-context.md) | Privilege Model | Adapter-registered ops are `Internal` by default |
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| [017](../../decisions/017-call-protocol-client-and-adapter-contract.md) | Call Protocol Client and Adapter Contract | `OperationAdapter` trait; `to_*` are projections; published-spec contract |
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| [022](../../decisions/022-handler-registration-provenance-and-composition-authority.md) | Handler Registration, Provenance, Composition Authority | `from_openapi`/`from_mcp` produce leaf bundles |
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| [023](../../decisions/023-operation-error-schemas.md) | Operation Error Schemas | `from_openapi`/`to_openapi` error fidelity; `HTTP_<status>` error codes |
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| [027](../../decisions/027-tls-identity-redesign-acme-rawkey-decoupling.md) | TLS Identity Redesign | Browsers require X.509; applies to WebTransport (deferred) and any browser-facing TLS |
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| [034](../../decisions/034-outgoing-only-x509-and-three-peer-roles.md) | Outgoing-Only X.509 and Three Peer Roles | Browsers are not alknet peers (§4 amended by ADR-044 §5 with the addressability rationale) |
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| [036](../../decisions/036-http-to-call-operation-mapping.md) | HTTP-to-Call Operation Mapping | Direct path mapping; `to_openapi` is projection, not router |
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| [037](../../decisions/037-mcp-stdio-transport-exclusion.md) | MCP Stdio Transport Exclusion | Streamable HTTP only; stdio not built |
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| [038](../../decisions/038-http3-and-webtransport-as-first-class.md) | HTTP/3 and WebTransport as First-Class HTTP Transports | **Superseded by ADR-044** (anti-pattern correction stands; specific decision reversed) |
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| [039](../../decisions/039-http-server-and-client-host-colocated.md) | HTTP Server and Client Host Colocated in alknet-http | One crate for server + client host (shared HTTP deps, shared mapping) |
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| [040](../../decisions/040-webtransport-alpn-stream-proxy.md) | WebTransport ALPN-Stream-Proxy | **Parked** per ADR-044; revives unchanged when WebTransport revives |
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| [041](../../decisions/041-mcp-tool-gateway-pattern.md) | MCP Tool-Gateway Pattern for to_mcp | 4 fixed gateway tools (search/schema/call/batch), not one tool per operation; Subscription excluded |
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| [042](../../decisions/042-openapi-gateway-pattern.md) | OpenAPI Gateway Pattern for to_openapi | 5 fixed gateway endpoints (search/schema/call/batch/subscribe), not one path per operation; per-caller AccessControl-filtered |
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| [043](../../decisions/043-webtransport-bidirectional-alpn-substrate.md) | WebTransport as a Bidirectional ALPN Transport Substrate | **Parked** per ADR-044; §2/§3 transfer to WebSocket for v1 |
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| [044](../../decisions/044-defer-webtransport-browsers-use-websocket.md) | Defer h3/WebTransport; Browsers Use WebSocket | `h3`/WebTransport deferred (scope); browser bidirectional path uses WebSocket; "browser is not a peer" rationale |
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## Relevant Open Questions
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| OQ | Title | Status | Relevance |
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|----|-------|--------|-----------|
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| OQ-11 | Handler-level auth resolution observability | resolved | HTTP handler stores resolved identity on `Connection` via `set_identity` |
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| OQ-12 | TLS identity provisioning | resolved | Browsers require X.509 (applies to WebTransport when it revives; WebSocket uses the same TLS as h2/http1.1) |
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| OQ-13 | Operation path format | resolved | `/{service}/{op}` is the HTTP path (ADR-036) |
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| OQ-17 | Call protocol client and adapter contract | resolved | `OperationAdapter` trait; `to_*` projections |
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| OQ-24 | Operation error schemas | resolved | `from_openapi`/`to_openapi` error fidelity |
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| OQ-26 | OperationAdapter error type | resolved | `AdapterError` variants reused by HTTP adapters |
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| OQ-37 | X.509 outgoing-only / three peer roles | resolved | Browsers are not peers; hub with mixed fingerprints |
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| OQ-38 | WebTransport standalone relay service scope | open (scope, not deferral) | The standalone relay (future `alknet-relay`, fork of iroh-relay) — distinct from the in-process ALPN-stream-proxy (ADR-040) |
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| OQ-39 | `to_openapi` published-spec versioning | open | Versioning strategy for generated OpenAPI specs |
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| OQ-40 | reqwest client config and connection pooling | resolved | `ClientWithMiddleware` + `RetryTransientMiddleware` + inlined `RetryAfterMiddleware`; rebuild-and-swap hot-reload |
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## Key Design Principles
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1. **HTTP is both a server surface and a client transport for adapters.**
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Inbound HTTP (`h2`/`http/1.1` + WebSocket upgrade) is served by `axum`
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over a QUIC stream; outbound HTTP (`from_openapi`/`from_mcp`
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forwarding) uses `reqwest`. Both directions share the same HTTP
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dependencies, which is why they live in one crate rather than being
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split. See [overview.md](overview.md).
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2. **The HTTP surface is a projection of the call protocol.** An HTTP
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request at `POST /fs/readFile` becomes a `call.requested` for
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`/fs/readFile`. The HTTP path IS the operation path on the
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**direct-call surface**. `to_openapi` *describes* a different surface
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— the 5-endpoint gateway (`/search`, `/schema`, `/call`, `/batch`,
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`/subscribe`) that gates discovery and invocation behind a fixed
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entry set. See [ADR-036](../../decisions/036-http-to-call-operation-mapping.md)
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(direct-call surface) and [ADR-042](../../decisions/042-openapi-gateway-pattern.md)
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(`to_openapi` gateway, superseding ADR-036's original `to_openapi`
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clause).
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3. **Standard ALPNs, not alknet ALPNs.** `h2`, `http/1.1` are
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IANA-registered ALPN strings. Any HTTP client (browser, curl, axios)
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connects without knowing about alknet — the TLS handshake negotiates
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`h2` or `http/1.1` normally. This is the stealth mapping (ADR-010).
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4. **`from_openapi`/`from_mcp` are the no-env-vars injection point.** The
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forwarding handlers read `context.capabilities`, not `std::env::var`.
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This is the architectural mechanism that makes aisdk's env-var reads
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unreachable. See ADR-014,
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[client-and-adapters.md](../call/client-and-adapters.md).
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5. **MCP streamable HTTP only; stdio is not built.** stdio = spawn
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arbitrary executable = RCE. Streamable HTTP is network-isolated,
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auth-gatable, and runs under alknet's auth model. See
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[ADR-037](../../decisions/037-mcp-stdio-transport-exclusion.md).
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6. **WebSocket is the browser bidirectional path.** A browser upgrades
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an HTTP/1.1 or HTTP/2 request to WebSocket and speaks the call
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protocol over binary WS messages — full-duplex, both sides can
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initiate calls (the call protocol's native bidirectionality, ADR-012).
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HTTP/3 + WebTransport (`h3`) is deferred per
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[ADR-044](../../decisions/044-defer-webtransport-browsers-use-websocket.md)
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— a scope decision (the browser bidirectional path doesn't require
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WebTransport's stream model; WebSocket suffices). The reversal
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trigger is a concrete ALPN-stream-proxy use case (a browser running
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a WASM SSH/SFTP/git client).
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7. **Browsers are not alknet peers.** A browser over WebSocket (or, when
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it revives, WebTransport) authenticates by bearer token, gets no
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`PeerId`, and its registered ops land in a connection-local Layer 2
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overlay. "Peer" means an addressable node in the call-protocol peer
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graph (stable `PeerId`, `PeerRef::Specific`-reachable, identity
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stable across reconnects) — not "any endpoint that exchanges calls
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during a live session." A browser is the second but not the first: no
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stable cryptographic identity of its own, ephemeral, not addressable
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from other nodes. See
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[ADR-034](../../decisions/034-outgoing-only-x509-and-three-peer-roles.md)
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§4 (amended by ADR-044 §5 with the addressability rationale).
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## References
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- `docs/research/alknet-http/phase-0-findings.md` — Phase 0 research
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(directionally close; DH-2's deferral framing was corrected by
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ADR-038, then ADR-038 was superseded by ADR-044 which re-defers
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`h3`/WebTransport as a genuine scope decision)
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- `docs/research/alknet-call-completion/gap-analysis.md` — adapter
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location map, no-env-vars invariant
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- `/workspace/@alkdev/operations/src/from_openapi.ts`,
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`/workspace/@alkdev/operations/src/from_mcp.ts` — TypeScript prior art
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- `/workspace/rust-sdk/` — MCP Rust SDK (rmcp v1.8.0); streamable HTTP
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transport examples
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- `/workspace/wtransport/` — pure-Rust WebTransport reference
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implementation (read during research; not a dependency. See ADR-044
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§"Research note" for why `wtransport` is probably not the right
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revival choice — the hyperium stack fits the axum integration better.) |