Piped input (#104)

* New method for handling stdin. Bypass Ink, and output to stdout. Makes the CLI work like a typical Unix application when called with piped input.

* Fixing a few post-merge errors.

* Format code.

* Clean up lint and format errors.

packages/cli/src/gemini.ts

@@ -8,16 +8,70 @@ import React from 'react';
 import { render } from 'ink';
 import { App } from './ui/App.js';
 import { loadCliConfig } from './config/config.js';
+import { readStdin } from './utils/readStdin.js';
+import { GeminiClient, ServerTool } from '@gemini-code/server';
+
+import { PartListUnion } from '@google/genai';
 
 async function main() {
+  let initialInput: string | undefined = undefined;
+
+  // Check if input is being piped
+  if (!process.stdin.isTTY) {
+    try {
+      initialInput = await readStdin();
+    } catch (error) {
+      console.error('Error reading from stdin:', error);
+      process.exit(1);
+    }
+  }
+
   // Load configuration
   const config = loadCliConfig();
-  // Render UI, passing necessary config values
+
-  render(
+  // Render UI, passing necessary config values and initial input
-    React.createElement(App, {
+  if (process.stdin.isTTY) {
-      config,
+    render(
-    }),
+      React.createElement(App, {
-  );
+        config,
+        initialInput,
+      }),
+    );
+  } else if (initialInput) {
+    // If not a TTY and we have initial input, process it directly
+    const geminiClient = new GeminiClient(
+      config.getApiKey(),
+      config.getModel(),
+    );
+    const toolRegistry = config.getToolRegistry();
+    const availableTools: ServerTool[] = toolRegistry.getAllTools();
+    const toolDeclarations = toolRegistry.getFunctionDeclarations();
+    const chat = await geminiClient.startChat(toolDeclarations);
+
+    const request: PartListUnion = [{ text: initialInput }];
+
+    try {
+      for await (const event of geminiClient.sendMessageStream(
+        chat,
+        request,
+        availableTools,
+      )) {
+        if (event.type === 'content') {
+          process.stdout.write(event.value);
+        }
+        // We might need to handle other event types later, but for now, just content.
+      }
+      process.stdout.write('\n'); // Add a newline at the end
+      process.exit(0);
+    } catch (error) {
+      console.error('Error processing piped input:', error);
+      process.exit(1);
+    }
+  } else {
+    // If not a TTY and no initial input, exit with an error
+    console.error('No input provided via stdin.');
+    process.exit(1);
+  }
 }
 
 // --- Global Unhandled Rejection Handler ---

packages/cli/src/ui/App.tsx

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import React, { useState, useMemo } from 'react';
+import React, { useState, useMemo, useEffect } from 'react'; // Added useEffect
 import { Box, Text } from 'ink';
 import { StreamingState, type HistoryItem } from './types.js';
 import { useGeminiStream } from './hooks/useGeminiStream.js';
@@ -25,9 +25,11 @@ import { Colors } from './colors.js';
 
 interface AppProps {
   config: Config;
+  initialInput?: string; // Added optional prop
 }
 
-export const App = ({ config }: AppProps) => {
+export const App = ({ config, initialInput }: AppProps) => {
+  // Destructured prop
   const [history, setHistory] = useState<HistoryItem[]>([]);
   const [startupWarnings, setStartupWarnings] = useState<string[]>([]);
   const { streamingState, submitQuery, initError, debugMessage } =
@@ -38,6 +40,15 @@ export const App = ({ config }: AppProps) => {
   useStartupWarnings(setStartupWarnings);
   useInitializationErrorEffect(initError, history, setHistory);
 
+  // Effect to handle initial piped input
+  useEffect(() => {
+    if (initialInput && initialInput.trim() !== '') {
+      submitQuery(initialInput);
+    }
+    // Run only once on mount
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
   const userMessages = useMemo(
     () =>
       history

packages/cli/src/ui/hooks/useStdin.ts

@@ -1,84 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { useState, useEffect } from 'react';
-import { useStdin } from 'ink';
-
-export interface PipedInputState {
-  data: string | null; // Use null initially to distinguish from empty string
-  isLoading: boolean;
-  error: string | null;
-  isPiped: boolean; // Flag to indicate if input was piped
-}
-
-export function usePipedInput(): PipedInputState {
-  const { stdin, setRawMode, isRawModeSupported } = useStdin();
-  // Keep exit available if needed, e.g., for error handling, but maybe let consumer handle it
-  // const { exit } = useApp();
-
-  const [pipedData, setPipedData] = useState<string | null>(null);
-  const [isLoading, setIsLoading] = useState<boolean>(true); // Assume loading until checked
-  const [error, setError] = useState<string | null>(null);
-  const [isPiped, setIsPiped] = useState<boolean>(false);
-
-  useEffect(() => {
-    // Determine if input is piped ONLY ONCE
-    const checkIsPiped = !stdin || !stdin.isTTY;
-    setIsPiped(checkIsPiped);
-
-    if (checkIsPiped) {
-      // Piped input detected
-      if (isRawModeSupported) {
-        setRawMode(false); // Ensure raw mode is off for stream reading
-      }
-
-      // Ensure stdin is available (it should be if !isTTY)
-      if (!stdin) {
-        setError('Stdin stream is unavailable.');
-        setIsLoading(false);
-        return; // Cannot proceed
-      }
-
-      let data = '';
-      const handleData = (chunk: Buffer) => {
-        data += chunk.toString();
-      };
-
-      const handleError = (err: Error) => {
-        setError('Error reading from stdin: ' + err.message);
-        setIsLoading(false);
-        // Decide if the hook should trigger exit or just report the error
-        // exit();
-      };
-
-      const handleEnd = () => {
-        setPipedData(data);
-        setIsLoading(false);
-        // Don't exit here, let the component using the hook decide
-      };
-
-      stdin.on('data', handleData);
-      stdin.on('error', handleError);
-      stdin.on('end', handleEnd);
-
-      // Cleanup listeners
-      return () => {
-        stdin.removeListener('data', handleData);
-        stdin.removeListener('error', handleError);
-        stdin.removeListener('end', handleEnd);
-      };
-    }
-
-    // No piped input (running interactively)
-    setIsLoading(false);
-    // Optionally set an 'info' state or just let isLoading=false & isPiped=false suffice
-    // setError('No piped input detected.'); // Maybe don't treat this as an 'error'
-
-    // Intentionally run only once on mount or when stdin theoretically changes
-  }, [stdin, isRawModeSupported, setRawMode /*, exit */]);
-
-  return { data: pipedData, isLoading, error, isPiped };
-}

packages/cli/src/utils/readStdin.ts

@@ -0,0 +1,27 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+export async function readStdin(): Promise<string> {
+  return new Promise((resolve, reject) => {
+    let data = '';
+    process.stdin.setEncoding('utf8');
+
+    process.stdin.on('readable', () => {
+      let chunk;
+      while ((chunk = process.stdin.read()) !== null) {
+        data += chunk;
+      }
+    });
+
+    process.stdin.on('end', () => {
+      resolve(data);
+    });
+
+    process.stdin.on('error', (err) => {
+      reject(err);
+    });
+  });
+}