openspec/lightweight-tasks/task1-2-4.md

feat: implement stream-json session handling and control requests

packages/cli/src/streamJson/input.ts

@@ -0,0 +1,132 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { createInterface } from 'node:readline/promises';
+import process from 'node:process';
+import {
+  parseStreamJsonEnvelope,
+  serializeStreamJsonEnvelope,
+  type StreamJsonControlRequestEnvelope,
+  type StreamJsonOutputEnvelope,
+  type StreamJsonUserEnvelope,
+} from './types.js';
+import { FatalInputError } from '@qwen-code/qwen-code-core';
+
+export interface ParsedStreamJsonInput {
+  prompt: string;
+}
+
+export async function readStreamJsonInput(): Promise<ParsedStreamJsonInput> {
+  const rl = createInterface({
+    input: process.stdin,
+    crlfDelay: Number.POSITIVE_INFINITY,
+    terminal: false,
+  });
+
+  try {
+    return await parseStreamJsonInputFromIterable(rl);
+  } finally {
+    rl.close();
+  }
+}
+
+export async function parseStreamJsonInputFromIterable(
+  lines: AsyncIterable<string>,
+  emitEnvelope: (envelope: StreamJsonOutputEnvelope) => void = writeEnvelope,
+): Promise<ParsedStreamJsonInput> {
+  const promptParts: string[] = [];
+  let receivedUserMessage = false;
+
+  for await (const rawLine of lines) {
+    const line = rawLine.trim();
+    if (!line) {
+      continue;
+    }
+
+    const envelope = parseStreamJsonEnvelope(line);
+
+    switch (envelope.type) {
+      case 'user':
+        promptParts.push(extractUserMessageText(envelope));
+        receivedUserMessage = true;
+        break;
+      case 'control_request':
+        handleControlRequest(envelope, emitEnvelope);
+        break;
+      case 'control_response':
+      case 'control_cancel_request':
+        // Currently ignored on CLI side.
+        break;
+      default:
+        throw new FatalInputError(
+          `Unsupported stream-json input type: ${envelope.type}`,
+        );
+    }
+  }
+
+  if (!receivedUserMessage) {
+    throw new FatalInputError(
+      'No user message provided via stream-json input.',
+    );
+  }
+
+  return {
+    prompt: promptParts.join('\n').trim(),
+  };
+}
+
+function handleControlRequest(
+  envelope: StreamJsonControlRequestEnvelope,
+  emitEnvelope: (envelope: StreamJsonOutputEnvelope) => void,
+) {
+  const subtype = envelope.request?.subtype;
+  if (subtype === 'initialize') {
+    emitEnvelope({
+      type: 'control_response',
+      request_id: envelope.request_id,
+      success: true,
+      response: {
+        subtype,
+        capabilities: {},
+      },
+    });
+    return;
+  }
+
+  emitEnvelope({
+    type: 'control_response',
+    request_id: envelope.request_id,
+    success: false,
+    error: `Unsupported control_request subtype: ${subtype ?? 'unknown'}`,
+  });
+}
+
+export function extractUserMessageText(
+  envelope: StreamJsonUserEnvelope,
+): string {
+  const content = envelope.message?.content;
+  if (typeof content === 'string') {
+    return content;
+  }
+  if (Array.isArray(content)) {
+    return content
+      .map((block) => {
+        if (block && typeof block === 'object' && 'type' in block) {
+          if (block.type === 'text' && 'text' in block) {
+            return block.text ?? '';
+          }
+          return JSON.stringify(block);
+        }
+        return '';
+      })
+      .join('\n');
+  }
+  return '';
+}
+
+function writeEnvelope(envelope: StreamJsonOutputEnvelope): void {
+  process.stdout.write(`${serializeStreamJsonEnvelope(envelope)}\n`);
+}