feat: integrate Pi backend and Pi Web

pi-web/lib/directory-browser.ts

@@ -0,0 +1,56 @@
+import { readdir, realpath, stat } from "fs/promises";
+import { homedir } from "os";
+import path from "path";
+
+export interface BrowsableDirectory {
+  name: string;
+  path: string;
+}
+
+export function getBrowseStartDirectory(directory?: string): string {
+  return directory || homedir();
+}
+
+export function normalizeDirectory(directory: string): string {
+  if (directory === "~") return homedir();
+  if (directory.startsWith("~/")) return path.resolve(homedir(), directory.slice(2));
+  return path.resolve(directory);
+}
+
+export function getParentDirectory(directory: string): string | null {
+  const pathApi = /^[a-zA-Z]:[\\/]/.test(directory) || directory.startsWith("\\\\")
+    ? path.win32
+    : path;
+  const normalized = pathApi.normalize(directory);
+  const parent = pathApi.dirname(normalized);
+  return parent === normalized ? null : parent;
+}
+
+export async function resolveDirectory(directory: string): Promise<string> {
+  return realpath(normalizeDirectory(directory));
+}
+
+export async function listDirectories(directory: string): Promise<BrowsableDirectory[]> {
+  const entries = await readdir(directory, { withFileTypes: true });
+  // 忽略损坏、不可访问或不指向目录的符号链接。
+  const candidates = await Promise.all(entries.map(async (entry) => {
+    if (entry.isDirectory()) {
+      return { name: entry.name, path: path.join(directory, entry.name) };
+    }
+    if (!entry.isSymbolicLink()) return null;
+
+    try {
+      const entryPath = path.join(directory, entry.name);
+      const realEntryPath = await realpath(entryPath);
+      const entryStat = await stat(realEntryPath);
+      if (!entryStat.isDirectory()) return null;
+      return { name: entry.name, path: entryPath };
+    } catch {
+      return null;
+    }
+  }));
+
+  return candidates
+    .filter((entry): entry is BrowsableDirectory => entry !== null)
+    .sort((left, right) => left.name.localeCompare(right.name));
+}