feat(server): native HttpApi listener with Bun.serve + WS upgrade (#25547)

2 files changed, 353 insertions, 0 deletions

diff --git a/packages/opencode/src/server/httpapi-listener.ts b/packages/opencode/src/server/httpapi-listener.ts
new file mode 100644
index 000000000..fd65b0ae6
--- /dev/null
+++ b/packages/opencode/src/server/httpapi-listener.ts
@@ -0,0 +1,244 @@
+// TODO: Node adapter forthcoming — same pattern but using `node:http` + `ws` library,
+// and `node:http`'s `upgrade` event.
+//
+// This module is a Bun-only proof-of-concept for a native `Bun.serve` listener that
+// drives the experimental HttpApi handler directly (no Hono in the middle) and handles
+// WebSocket upgrades inline based on path-matching. It exists to validate the pattern
+// before deleting the Hono backend; `Server.listen()` is intentionally NOT wired to it.
+
+import type { ServerWebSocket } from "bun"
+import { Effect, Schema } from "effect"
+import { AppRuntime } from "@/effect/app-runtime"
+import { WithInstance } from "@/project/with-instance"
+import { Pty } from "@/pty"
+import { handlePtyInput } from "@/pty/input"
+import { PtyID } from "@/pty/schema"
+import { PtyPaths } from "@/server/routes/instance/httpapi/groups/pty"
+import { ExperimentalHttpApiServer } from "@/server/routes/instance/httpapi/server"
+import * as Log from "@opencode-ai/core/util/log"
+import type { CorsOptions } from "./cors"
+
+const log = Log.create({ service: "httpapi-listener" })
+const decodePtyID = Schema.decodeUnknownSync(PtyID)
+
+export type Listener = {
+  hostname: string
+  port: number
+  url: URL
+  stop: (close?: boolean) => Promise<void>
+}
+
+export type ListenOptions = CorsOptions & {
+  port: number
+  hostname: string
+}
+
+type WsKind = { kind: "pty"; ptyID: string; cursor: number | undefined; directory: string }
+
+type PtyHandler = {
+  onMessage: (message: string | ArrayBuffer) => void
+  onClose: () => void
+}
+
+type WsState = WsKind & {
+  handler?: PtyHandler
+  pending: Array<string | Uint8Array>
+  ready: boolean
+  closed: boolean
+}
+
+// Derive from the OpenAPI path so this stays in sync if the route literal moves.
+const ptyConnectPattern = new RegExp(`^${PtyPaths.connect.replace(/:[^/]+/g, "([^/]+)")}$`)
+
+function parseCursor(value: string | null): number | undefined {
+  if (!value) return undefined
+  const parsed = Number(value)
+  if (!Number.isSafeInteger(parsed) || parsed < -1) return undefined
+  return parsed
+}
+
+function asAdapter(ws: ServerWebSocket<WsState>) {
+  return {
+    get readyState() {
+      return ws.readyState
+    },
+    send: (data: string | Uint8Array | ArrayBuffer) => {
+      try {
+        if (data instanceof ArrayBuffer) ws.send(new Uint8Array(data))
+        else ws.send(data)
+      } catch {
+        // socket likely already closed; ignore
+      }
+    },
+    close: (code?: number, reason?: string) => {
+      try {
+        ws.close(code, reason)
+      } catch {
+        // ignore
+      }
+    },
+  }
+}
+
+/**
+ * Spin up a native Bun.serve that:
+ *   1. Routes all HTTP traffic through the HttpApi web handler.
+ *   2. Intercepts known WebSocket upgrade paths and handles them inline.
+ *
+ * This bypasses Hono entirely. The Hono code path remains untouched.
+ */
+export async function listen(opts: ListenOptions): Promise<Listener> {
+  const built = ExperimentalHttpApiServer.webHandler(opts)
+  const handler = built.handler
+  const context = ExperimentalHttpApiServer.context
+
+  const start = (port: number) => {
+    try {
+      return Bun.serve<WsState>({
+        hostname: opts.hostname,
+        port,
+        idleTimeout: 0,
+        fetch(request, server) {
+          const url = new URL(request.url)
+          const ptyMatch = url.pathname.match(ptyConnectPattern)
+          if (ptyMatch && request.headers.get("upgrade")?.toLowerCase() === "websocket") {
+            const ptyID = ptyMatch[1]!
+            const cursor = parseCursor(url.searchParams.get("cursor"))
+            // Resolve the instance directory the same way the HttpApi
+            // `instance-context` middleware does (search params, then header,
+            // then process.cwd()).
+            const directory =
+              url.searchParams.get("directory") ?? request.headers.get("x-opencode-directory") ?? process.cwd()
+            const upgraded = server.upgrade(request, {
+              data: {
+                kind: "pty",
+                ptyID,
+                cursor,
+                directory,
+                pending: [],
+                ready: false,
+                closed: false,
+              } satisfies WsState,
+            })
+            if (upgraded) return undefined
+            return new Response("upgrade failed", { status: 400 })
+          }
+
+          // TODO: workspace-proxy WS upgrade detection. The Hono path forwards via a
+          // remote `new WebSocket(url, ...)` (see ServerProxy.websocket). To support
+          // that here we'd need to (a) resolve the workspace target the same way
+          // `WorkspaceRouterMiddleware` does today, then (b) `server.upgrade(request,
+          // { data: { kind: "proxy", target, headers, protocols } })` and bridge the
+          // ServerWebSocket to a remote WebSocket inside the `websocket` handlers.
+          // Deferred to a follow-up — the proxy story needs more design (auth header
+          // forwarding, fence sync, reconnection semantics) than fits this PR.
+
+          return handler(request as Request, context as never)
+        },
+        websocket: {
+          open(ws) {
+            const data = ws.data
+            if (data.kind !== "pty") {
+              ws.close(1011, "unknown ws kind")
+              return
+            }
+            const id = (() => {
+              try {
+                return decodePtyID(data.ptyID)
+              } catch {
+                ws.close(1008, "invalid pty id")
+                return undefined
+              }
+            })()
+            if (!id) return
+            ;(async () => {
+              const result = await WithInstance.provide({
+                directory: data.directory,
+                fn: () =>
+                  AppRuntime.runPromise(
+                    Effect.gen(function* () {
+                      const pty = yield* Pty.Service
+                      return yield* pty.connect(id, asAdapter(ws), data.cursor)
+                    }).pipe(Effect.withSpan("HttpApiListener.pty.connect.open")),
+                  ),
+              })
+              return await result
+            })()
+              .then((handler) => {
+                if (data.closed) {
+                  handler?.onClose()
+                  return
+                }
+                if (!handler) {
+                  ws.close(4404, "session not found")
+                  return
+                }
+                data.handler = handler
+                data.ready = true
+                for (const msg of data.pending) {
+                  AppRuntime.runPromise(handlePtyInput(handler, msg)).catch(() => undefined)
+                }
+                data.pending.length = 0
+              })
+              .catch((err) => {
+                log.error("pty connect failed", { error: err })
+                ws.close(1011, "pty connect failed")
+              })
+          },
+          message(ws, message) {
+            const data = ws.data
+            if (data.kind !== "pty") return
+            const payload =
+              typeof message === "string"
+                ? message
+                : message instanceof Buffer
+                  ? new Uint8Array(message.buffer, message.byteOffset, message.byteLength)
+                  : (message as Uint8Array)
+            if (!data.ready || !data.handler) {
+              data.pending.push(payload)
+              return
+            }
+            AppRuntime.runPromise(handlePtyInput(data.handler, payload)).catch(() => undefined)
+          },
+          close(ws) {
+            const data = ws.data
+            data.closed = true
+            data.handler?.onClose()
+          },
+        },
+      })
+    } catch (err) {
+      log.error("Bun.serve failed", { error: err })
+      return undefined
+    }
+  }
+
+  const server = opts.port === 0 ? (start(4096) ?? start(0)) : start(opts.port)
+  if (!server) throw new Error(`Failed to start server on port ${opts.port}`)
+  const port = server.port
+  if (port === undefined) throw new Error("Bun.serve started without a numeric port")
+
+  const url = new URL("http://localhost")
+  url.hostname = opts.hostname
+  url.port = String(port)
+
+  let closing: Promise<void> | undefined
+  return {
+    hostname: opts.hostname,
+    port,
+    url,
+    stop(close?: boolean) {
+      closing ??= (async () => {
+        await server.stop(close)
+        // NOTE: we deliberately do NOT call `built.dispose()` here. The
+        // underlying `webHandler` is memoized at module level (same as the
+        // Hono path), so disposing it would tear down shared services for
+        // every other consumer in the process. Lifecycle teardown is owned
+        // by the AppRuntime itself.
+      })()
+      return closing
+    },
+  }
+}
+
+export * as HttpApiListener from "./httpapi-listener"
diff --git a/packages/opencode/test/server/httpapi-listener.test.ts b/packages/opencode/test/server/httpapi-listener.test.ts
new file mode 100644
index 000000000..de7b5987e
--- /dev/null
+++ b/packages/opencode/test/server/httpapi-listener.test.ts
@@ -0,0 +1,109 @@
+import { afterEach, describe, expect, test } from "bun:test"
+import { Flag } from "@opencode-ai/core/flag/flag"
+import * as Log from "@opencode-ai/core/util/log"
+import { resetDatabase } from "../fixture/db"
+import { disposeAllInstances, tmpdir } from "../fixture/fixture"
+import { HttpApiListener } from "../../src/server/httpapi-listener"
+import { PtyPaths } from "../../src/server/routes/instance/httpapi/groups/pty"
+
+void Log.init({ print: false })
+
+const original = Flag.OPENCODE_EXPERIMENTAL_HTTPAPI
+const testPty = process.platform === "win32" ? test.skip : test
+
+afterEach(async () => {
+  Flag.OPENCODE_EXPERIMENTAL_HTTPAPI = original
+  await disposeAllInstances()
+  await resetDatabase()
+})
+
+async function startListener() {
+  Flag.OPENCODE_EXPERIMENTAL_HTTPAPI = true
+  return HttpApiListener.listen({ hostname: "127.0.0.1", port: 0 })
+}
+
+describe("native HttpApi listener", () => {
+  test("serves HTTP routes via the HttpApi web handler", async () => {
+    await using tmp = await tmpdir({ git: true, config: { formatter: false, lsp: false } })
+    const listener = await startListener()
+    try {
+      const response = await fetch(`${listener.url.origin}${PtyPaths.shells}`, {
+        headers: { "x-opencode-directory": tmp.path },
+      })
+      expect(response.status).toBe(200)
+      const body = await response.json()
+      expect(Array.isArray(body)).toBe(true)
+      expect(body[0]).toMatchObject({
+        path: expect.any(String),
+        name: expect.any(String),
+        acceptable: expect.any(Boolean),
+      })
+    } finally {
+      await listener.stop(true)
+    }
+  })
+
+  testPty("PTY websocket connect echoes input back to the client", async () => {
+    await using tmp = await tmpdir({ git: true, config: { formatter: false, lsp: false } })
+    const listener = await startListener()
+    try {
+      const created = await fetch(`${listener.url.origin}${PtyPaths.create}`, {
+        method: "POST",
+        headers: {
+          "x-opencode-directory": tmp.path,
+          "content-type": "application/json",
+        },
+        body: JSON.stringify({ command: "/bin/cat", title: "listener-smoke" }),
+      })
+      expect(created.status).toBe(200)
+      const info = (await created.json()) as { id: string }
+
+      try {
+        const wsURL = new URL(PtyPaths.connect.replace(":ptyID", info.id), listener.url)
+        wsURL.protocol = "ws:"
+        wsURL.searchParams.set("directory", tmp.path)
+        wsURL.searchParams.set("cursor", "-1")
+
+        const messages: string[] = []
+        const ws = new WebSocket(wsURL)
+        ws.binaryType = "arraybuffer"
+
+        const opened = new Promise<void>((resolve, reject) => {
+          ws.addEventListener("open", () => resolve(), { once: true })
+          ws.addEventListener("error", () => reject(new Error("ws error before open")), { once: true })
+        })
+
+        const closed = new Promise<void>((resolve) => {
+          ws.addEventListener("close", () => resolve(), { once: true })
+        })
+
+        ws.addEventListener("message", (event) => {
+          const data = event.data
+          messages.push(typeof data === "string" ? data : new TextDecoder().decode(data as ArrayBuffer))
+        })
+
+        await opened
+        ws.send("ping-listener\n")
+
+        const start = Date.now()
+        while (!messages.some((m) => m.includes("ping-listener")) && Date.now() - start < 5_000) {
+          await new Promise((r) => setTimeout(r, 50))
+        }
+        ws.close(1000, "done")
+
+        expect(messages.some((m) => m.includes("ping-listener"))).toBe(true)
+        // Verify close event fires (handler.onClose path runs and the
+        // Bun.serve websocket lifecycle reaches close).
+        await closed
+        expect(ws.readyState).toBe(WebSocket.CLOSED)
+      } finally {
+        await fetch(`${listener.url.origin}${PtyPaths.remove.replace(":ptyID", info.id)}`, {
+          method: "DELETE",
+          headers: { "x-opencode-directory": tmp.path },
+        }).catch(() => undefined)
+      }
+    } finally {
+      await listener.stop(true)
+    }
+  })
+})