feat: support general chat file attachments

src/server/sessions/attachmentService.test.ts

@@ -1,17 +1,22 @@
-import { mkdtemp, readFile, readdir, rm } from "node:fs/promises";
+import { mkdir, mkdtemp, readFile, readdir, rm, symlink } from "node:fs/promises";
 import { join } from "node:path";
 import { tmpdir } from "node:os";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { DEFAULT_ATTACHMENT_FOLDER, saveAttachmentsToWorkspace } from "./attachmentService.js";
 
 let workspace: string;
+let externalDirectories: string[] = [];
 
 beforeEach(async () => {
   workspace = await mkdtemp(join(tmpdir(), "pi-web-attachments-"));
+  externalDirectories = [];
 });
 
 afterEach(async () => {
-  await rm(workspace, { recursive: true, force: true });
+  await Promise.all([
+    rm(workspace, { recursive: true, force: true }),
+    ...externalDirectories.map((directory) => rm(directory, { recursive: true, force: true })),
+  ]);
 });
 
 const pngBytes = Buffer.from([0x89, 0x50, 0x4e, 0x47]);
@@ -43,6 +48,59 @@ describe("saveAttachmentsToWorkspace", () => {
     expect(written.equals(pngBytes)).toBe(true);
   });
 
+  it("saves generic files with sanitized original filenames", async () => {
+    const pdfBytes = Buffer.from("PDF bytes");
+    const saved = await saveAttachmentsToWorkspace(
+      workspace,
+      [
+        { kind: "file", mimeType: "application/pdf", data: pdfBytes.toString("base64"), name: "../Quarterly Report (final).pdf" },
+        { kind: "file", mimeType: "text/plain", data: "", name: "empty.txt" },
+      ],
+      { now: () => new Date("2026-06-13T12:05:01.123Z") },
+    );
+
+    expect(saved[0]?.path.startsWith(`${DEFAULT_ATTACHMENT_FOLDER}/attachment-`)).toBe(true);
+    expect(saved[0]?.path.endsWith("-1-Quarterly-Report-final.pdf")).toBe(true);
+    expect(saved[0]).toMatchObject({ mimeType: "application/pdf", size: pdfBytes.byteLength });
+    expect(saved[1]?.path.endsWith("-2-empty.txt")).toBe(true);
+    expect(saved[1]).toMatchObject({ mimeType: "text/plain", size: 0 });
+
+    expect((await readFile(join(workspace, saved[0]?.path ?? ""))).equals(pdfBytes)).toBe(true);
+    expect(await readFile(join(workspace, saved[1]?.path ?? ""))).toHaveLength(0);
+  });
+
+  it("does not overwrite an existing attachment name", async () => {
+    const fixedNow = () => new Date("2026-06-13T12:05:01.123Z");
+    const first = await saveAttachmentsToWorkspace(
+      workspace,
+      [{ kind: "file", mimeType: "text/plain", data: "QUJD", name: "note.txt" }],
+      { now: fixedNow },
+    );
+    const second = await saveAttachmentsToWorkspace(
+      workspace,
+      [{ kind: "file", mimeType: "text/plain", data: "REVG", name: "note.txt" }],
+      { now: fixedNow },
+    );
+
+    expect(second[0]?.path).not.toBe(first[0]?.path);
+    expect(second[0]?.path.endsWith("-1-note-2.txt")).toBe(true);
+    expect((await readFile(join(workspace, first[0]?.path ?? ""))).toString()).toBe("ABC");
+    expect((await readFile(join(workspace, second[0]?.path ?? ""))).toString()).toBe("DEF");
+  });
+
+  it("rejects unsafe custom folders", async () => {
+    await expect(saveAttachmentsToWorkspace(
+      workspace,
+      [{ kind: "image", mimeType: "image/png", data: pngBase64 }],
+      { folder: "/tmp/uploads" },
+    )).rejects.toThrow(/Absolute paths/);
+    await expect(saveAttachmentsToWorkspace(
+      workspace,
+      [{ kind: "image", mimeType: "image/png", data: pngBase64 }],
+      { folder: "../uploads" },
+    )).rejects.toThrow(/Path traversal/);
+  });
+
   it("honors a custom folder", async () => {
     const saved = await saveAttachmentsToWorkspace(
       workspace,
@@ -52,6 +110,19 @@ describe("saveAttachmentsToWorkspace", () => {
     expect(saved[0]?.path.startsWith("uploads/images/")).toBe(true);
   });
 
+  it("rejects attachment folders that resolve outside the workspace", async () => {
+    const outside = await mkdtemp(join(tmpdir(), "pi-web-attachments-outside-"));
+    externalDirectories.push(outside);
+    await mkdir(join(workspace, ".pi-web"));
+    await symlink(outside, join(workspace, ".pi-web", "attachments"), "dir");
+
+    await expect(saveAttachmentsToWorkspace(
+      workspace,
+      [{ kind: "file", mimeType: "text/plain", data: "QUJD", name: "note.txt" }],
+    )).rejects.toThrow(/Path escapes workspace/);
+    await expect(readdir(outside)).resolves.toEqual([]);
+  });
+
   it("returns empty for no attachments", async () => {
     expect(await saveAttachmentsToWorkspace(workspace, [])).toEqual([]);
   });