2026-02-12 13:37:40 -08:00

142 lines
3.5 KiB
TypeScript

import type { UIMessage } from "ai";
import { resolveAgentWorkspacePrefix } from "@/lib/workspace";
import {
startRun,
hasActiveRun,
subscribeToRun,
persistUserMessage,
type SseEvent,
} from "@/lib/active-runs";
// Force Node.js runtime (required for child_process)
export const runtime = "nodejs";
// Allow streaming responses up to 10 minutes
export const maxDuration = 600;
export async function POST(req: Request) {
const {
messages,
sessionId,
}: { messages: UIMessage[]; sessionId?: string } = await req.json();
// Extract the latest user message text
const lastUserMessage = messages.filter((m) => m.role === "user").pop();
const userText =
lastUserMessage?.parts
?.filter(
(p): p is { type: "text"; text: string } =>
p.type === "text",
)
.map((p) => p.text)
.join("\n") ?? "";
if (!userText.trim()) {
return new Response("No message provided", { status: 400 });
}
// Reject if a run is already active for this session.
if (sessionId && hasActiveRun(sessionId)) {
return new Response("Active run in progress", { status: 409 });
}
// Resolve workspace file paths to be agent-cwd-relative.
let agentMessage = userText;
const wsPrefix = resolveAgentWorkspacePrefix();
if (wsPrefix) {
agentMessage = userText.replace(
/\[Context: workspace file '([^']+)'\]/,
`[Context: workspace file '${wsPrefix}/$1']`,
);
}
// Persist the user message server-side so it survives a page reload
// even if the client never gets a chance to save.
if (sessionId && lastUserMessage) {
persistUserMessage(sessionId, {
id: lastUserMessage.id,
content: userText,
parts: lastUserMessage.parts as unknown[],
});
}
// Start the agent run (decoupled from this HTTP connection).
// The child process will keep running even if this response is cancelled.
if (sessionId) {
try {
startRun({
sessionId,
message: agentMessage,
agentSessionId: sessionId,
});
} catch (err) {
return new Response(
err instanceof Error ? err.message : String(err),
{ status: 500 },
);
}
}
// Stream SSE events to the client using the AI SDK v6 wire format.
const encoder = new TextEncoder();
let closed = false;
let unsubscribe: (() => void) | null = null;
const stream = new ReadableStream({
start(controller) {
if (!sessionId) {
// No session — shouldn't happen but close gracefully.
controller.close();
return;
}
unsubscribe = subscribeToRun(
sessionId,
(event: SseEvent | null) => {
if (closed) {return;}
if (event === null) {
// Run completed — close the SSE stream.
closed = true;
try {
controller.close();
} catch {
/* already closed */
}
return;
}
try {
const json = JSON.stringify(event);
controller.enqueue(
encoder.encode(`data: ${json}\n\n`),
);
} catch {
/* ignore enqueue errors on closed stream */
}
},
// Don't replay — we just created the run, the buffer is empty.
{ replay: false },
);
if (!unsubscribe) {
// Race: run was cleaned up between startRun and subscribe.
closed = true;
controller.close();
}
},
cancel() {
// Client disconnected — unsubscribe but keep the run alive.
// The ActiveRunManager continues buffering + persisting in the background.
closed = true;
unsubscribe?.();
},
});
return new Response(stream, {
headers: {
"Content-Type": "text/event-stream",
"Cache-Control": "no-cache, no-transform",
Connection: "keep-alive",
},
});
}