feat: add copy on ctrl/command+shift+c and selection to web terminal (#20129)

Closes https://github.com/coder/coder/issues/20044

site/src/pages/TerminalPage/TerminalPage.tsx

@@ -14,6 +14,7 @@ import {
 } from "api/queries/workspaces";
 import { useProxy } from "contexts/ProxyContext";
 import { ThemeOverride } from "contexts/ThemeProvider";
+import { useClipboard } from "hooks/useClipboard";
 import { useEmbeddedMetadata } from "hooks/useEmbeddedMetadata";
 import { type FC, useCallback, useEffect, useRef, useState } from "react";
 import { useQuery } from "react-query";
@@ -80,6 +81,8 @@ const TerminalPage: FC = () => {
 	const config = useQuery(deploymentConfig());
 	const renderer = config.data?.config.web_terminal_renderer;
 
+	const { copyToClipboard } = useClipboard();
+
 	// Periodically report workspace usage.
 	useQuery(
 		workspaceUsage({
@@ -147,12 +150,21 @@ const TerminalPage: FC = () => {
 			}),
 		);
 
-		// Make shift+enter send ^[^M (escaped carriage return).  Applications
-		// typically take this to mean to insert a literal newline.  There is no way
-		// to remove this handler, so we must attach it once and rely on a ref to
-		// send it to the current socket.
+		const isMac = navigator.platform.match("Mac");
+
+		const copySelection = () => {
+			const selection = terminal.getSelection();
+			if (selection) {
+				copyToClipboard(selection);
+			}
+		};
+
+		// There is no way to remove this handler, so we must attach it once and
+		// rely on a ref to send it to the current socket.
 		const escapedCarriageReturn = "\x1b\r";
 		terminal.attachCustomKeyEventHandler((ev) => {
+			// Make shift+enter send ^[^M (escaped carriage return).  Applications
+			// typically take this to mean to insert a literal newline.
 			if (ev.shiftKey && ev.key === "Enter") {
 				if (ev.type === "keydown") {
 					websocketRef.current?.send(
@@ -163,9 +175,36 @@ const TerminalPage: FC = () => {
 				}
 				return false;
 			}
+			// Make ctrl+shift+c (command+shift+c on macOS) copy the selected text.
+			// By default this usually launches the browser dev tools, but users
+			// expect this keybinding to copy when in the context of the web terminal.
+			if ((isMac ? ev.metaKey : ev.ctrlKey) && ev.shiftKey && ev.key === "C") {
+				ev.preventDefault();
+				if (ev.type === "keydown") {
+					copySelection();
+				}
+				return false;
+			}
 			return true;
 		});
 
+		// Copy using the clipboard API on selection.  This selected text will go
+		// into the clipboard, not the primary selection, as the browser does not
+		// give us an API to set the primary selection (only relevant to systems
+		// that have this distinction, like X11).
+		//
+		// We could bind the middle mouse button to paste from the clipboard to
+		// compensate, but then we would break pasting selections from external
+		// applications into the web terminal.  Not sure which tradeoff is worse; it
+		// probably varies between users.
+		//
+		// In other words, this copied text can be pasted with a keybinding
+		// (typically ctrl+v, ctrl+shift+v, or shift+insert), but *not* with the
+		// middle mouse button.
+		terminal.onSelectionChange(() => {
+			copySelection();
+		});
+
 		terminal.open(terminalWrapperRef.current);
 
 		// We have to fit twice here. It's unknown why, but the first fit will
@@ -189,6 +228,7 @@ const TerminalPage: FC = () => {
 		renderer,
 		theme.palette.background.default,
 		currentTerminalFont,
+		copyToClipboard,
 	]);
 
 	// Updates the reconnection token into the URL if necessary.