feat: separate frontend and backend services

server/src/lib/bash-output.ts

@@ -0,0 +1,53 @@
+import { constants } from "node:fs";
+import { lstat, open } from "node:fs/promises";
+import { basename, dirname, resolve } from "node:path";
+
+export const MAX_INLINE_BASH_OUTPUT_BYTES = 5 * 1024 * 1024;
+
+export function resolveBashOutputPath(filePath: string, tempRoot: string): string | null {
+  const resolvedPath = resolve(filePath);
+  if (dirname(resolvedPath) !== resolve(tempRoot)) return null;
+  if (!/^pi-bash-[A-Za-z0-9_-]+\.log$/.test(basename(resolvedPath))) return null;
+  return resolvedPath;
+}
+
+export async function openRegularFileNoFollow(filePath: string) {
+  const pathInfo = await lstat(filePath);
+  if (!pathInfo.isFile()) throw new Error("Bash output path is not a regular file");
+
+  const noFollow = typeof constants.O_NOFOLLOW === "number" ? constants.O_NOFOLLOW : 0;
+  const handle = await open(filePath, constants.O_RDONLY | noFollow);
+  try {
+    const fileInfo = await handle.stat();
+    if (!fileInfo.isFile()) throw new Error("Bash output path is not a regular file");
+    return { handle, fileInfo };
+  } catch (error) {
+    await handle.close();
+    throw error;
+  }
+}
+
+export async function readUtf8FileWithinLimit(
+  filePath: string,
+  maxBytes = MAX_INLINE_BASH_OUTPUT_BYTES,
+): Promise<{ tooLarge: true; size: number } | { tooLarge: false; content: string; size: number }> {
+  const { handle, fileInfo } = await openRegularFileNoFollow(filePath);
+  try {
+    if (fileInfo.size > maxBytes) return { tooLarge: true, size: fileInfo.size };
+
+    const buffer = Buffer.alloc(fileInfo.size);
+    let bytesRead = 0;
+    while (bytesRead < buffer.length) {
+      const result = await handle.read(buffer, bytesRead, buffer.length - bytesRead, bytesRead);
+      if (result.bytesRead === 0) break;
+      bytesRead += result.bytesRead;
+    }
+    return {
+      tooLarge: false,
+      content: buffer.subarray(0, bytesRead).toString("utf8"),
+      size: bytesRead,
+    };
+  } finally {
+    await handle.close();
+  }
+}