fix: Document title with slashes produces folders in exported zip file

closes #2036

server/utils/fs.js

@@ -2,6 +2,14 @@
 import path from "path";
 import fs from "fs-extra";
 
+export function serializeFilename(text: string): string {
+  return text.replace(/\//g, "%2F").replace(/\\/g, "%5C");
+}
+
+export function deserializeFilename(text: string): string {
+  return text.replace(/%2F/g, "/").replace(/%5C/g, "\\");
+}
+
 export function requireDirectory<T>(dirName: string): [T, string][] {
   return fs
     .readdirSync(dirName)

server/utils/fs.test.js

@@ -0,0 +1,34 @@
+// @flow
+import { serializeFilename, deserializeFilename } from "./fs";
+
+describe("serializeFilename", () => {
+  it("should serialize forward slashes", () => {
+    expect(serializeFilename(`/`)).toBe("%2F");
+    expect(serializeFilename(`this / and / this`)).toBe(
+      "this %2F and %2F this"
+    );
+  });
+
+  it("should serialize back slashes", () => {
+    expect(serializeFilename(`\\`)).toBe("%5C");
+    expect(serializeFilename(`this \\ and \\ this`)).toBe(
+      "this %5C and %5C this"
+    );
+  });
+});
+
+describe("deserializeFilename", () => {
+  it("should deserialize forward slashes", () => {
+    expect(deserializeFilename("%2F")).toBe("/");
+    expect(deserializeFilename("this %2F and %2F this")).toBe(
+      `this / and / this`
+    );
+  });
+
+  it("should deserialize back slashes", () => {
+    expect(deserializeFilename("%5C")).toBe(`\\`);
+    expect(deserializeFilename("this %5C and %5C this")).toBe(
+      `this \\ and \\ this`
+    );
+  });
+});

server/utils/zip.js

@@ -4,6 +4,7 @@ import * as Sentry from "@sentry/node";
 import JSZip from "jszip";
 import tmp from "tmp";
 import { Attachment, Collection, Document } from "../models";
+import { serializeFilename } from "./fs";
 import { getFileByKey } from "./s3";
 
 async function addToArchive(zip, documents) {
@@ -23,7 +24,9 @@ async function addToArchive(zip, documents) {
       text = text.replace(attachment.redirectUrl, encodeURI(attachment.key));
     }
 
-    zip.file(`${document.title || "Untitled"}.md`, text, {
+    const title = serializeFilename(document.title) || "Untitled";
+
+    zip.file(`${title}.md`, text, {
       date: document.updatedAt,
       comment: JSON.stringify({
         pinned: document.pinned,
@@ -33,7 +36,7 @@ async function addToArchive(zip, documents) {
     });
 
     if (doc.children && doc.children.length) {
-      const folder = zip.folder(document.title);
+      const folder = zip.folder(title);
       await addToArchive(folder, doc.children);
     }
   }