♻️ backend: move editing_session_key generation and parsing to specif…

…ic implementation (#525)

Documentation/docs/plugins.md

@@ -43,7 +43,7 @@ Links in top right drop down application grid can be configured in the `applicat
 
 Plugins are defined as entries under the `applications.plugins` array, with at least the following properties:
 
-- `id` is mandatory and must be unique to each plugin
+- `id` is mandatory and must be unique to each plugin. It must be rather short, and alphanumeric with `_`s only.
 - `internal_domain` is the internal domain of the plugin's server, it must be the same as the one in the docker-compose.yml file for ex. or resolvable and accessible to the Twake Drive backend server.
 - `external_prefix` is the external URL prefix of the plugin exposed by the backend and proxied to the `internal_domain`.
 - `api.private_key` is the shared secret used by the plugin's server to authentify to the backend

tdrive/backend/node/src/services/documents/entities/drive-file.ts

@@ -1,4 +1,5 @@
 import { Type } from "class-transformer";
+import { randomUUID } from "crypto";
 import { Column, Entity } from "../../../core/platform/services/database/services/orm/decorators";
 import { DriveFileAccessLevel, publicAccessLevel } from "../types";
 import { FileVersion } from "./file-version";
@@ -93,8 +94,9 @@ export class DriveFile {
 
   /**
    * If this field is non-null, then an editing session is in progress (probably in OnlyOffice).
-   * Should be in the format `timestamp-appid-hexuuid` where `appid` and `timestamp` have no `-`
-   * characters.
+   * Use {@see EditingSessionKeyFormat} to generate and interpret it.
+   * Values should ensure that sorting lexicographically is chronological (assuming perfect clocks everywhere),
+   * and that the application and user that started the edit session are retrievable.
    */
   @Type(() => String)
   @Column("editing_session_key", "string")
@@ -120,6 +122,81 @@ export class DriveFile {
   scope: DriveScope;
 }
 
+/** Reference implementation for generating then parsing the {@link DriveFile.editing_session_key} field */
+export const EditingSessionKeyFormat = {
+  // OnlyOffice key limits: 128 chars, [0-9a-zA-z=_-]
+  // This is specific to it, but the constraint seems strict enough
+  // that any other system needing such a unique identifier would find
+  // this compatible. This value must be ensured to be the strictest
+  // common denominator to all plugin/interop systems. Plugins that
+  // require something even stricter have the option of maintaining
+  // a look up table to an acceptable value.
+  generate(applicationId: string, userId: string) {
+    if (!/^[0-9a-zA-Z_-]+$/m.test(applicationId))
+      throw new Error(
+        `Invalid applicationId string (${JSON.stringify(
+          applicationId,
+        )}). Must be short and only alpha numeric`,
+      );
+    const isoUTCDateNoSpecialCharsNoMS = new Date()
+      .toISOString()
+      .replace(/\..+$/, "")
+      .replace(/[ZT:-]/g, "");
+    const newKey = [
+      isoUTCDateNoSpecialCharsNoMS,
+      applicationId,
+      userId.replace(/-+/g, ""),
+      randomUUID().replace(/-+/g, ""),
+    ].join("=");
+    if (newKey.length > 128 || !/^[0-9a-zA-Z=_-]+$/m.test(newKey))
+      throw new Error(
+        `Invalid generated editingSessionKey (${JSON.stringify(
+          newKey,
+        )}) string. Must be <128 chars, and only contain [0-9a-zA-z=_-]`,
+      );
+    return newKey;
+  },
+
+  parse(editingSessionKey: string) {
+    const parts = editingSessionKey.split("=");
+    const expectedParts = 4;
+    if (parts.length !== expectedParts)
+      throw new Error(
+        `Invalid editingSessionKey (${JSON.stringify(
+          editingSessionKey,
+        )}). Expected ${expectedParts} parts`,
+      );
+    const [timestampStr, appId, userId, _random] = parts;
+    const timestampMatch = timestampStr.match(
+      /^(?<year>\d{4})(?<month>\d\d)(?<day>\d\d)(?<hour>\d\d)(?<minute>\d\d)(?<second>\d\d)$/,
+    );
+    if (!timestampMatch)
+      throw new Error(
+        `Invalid editingSessionKey (${JSON.stringify(
+          editingSessionKey,
+        )}). Didn't start with valid timestamp`,
+      );
+    const { year, month, day, hour, minute, second } = timestampMatch.groups!;
+    const userIdMatch = userId.match(
+      /^([a-z0-f]{8})([a-z0-f]{4})([a-z0-f]{4})([a-z0-f]{4})([a-z0-f]{12})$/i,
+    );
+    if (!userIdMatch)
+      throw new Error(
+        `Invalid editingSessionKey (${JSON.stringify(
+          editingSessionKey,
+        )}). UserID has wrong number of digits`,
+      );
+    const [, userIdPart1, userIdPart2, userIdPart3, userIdPart4, userIdPart5] = userIdMatch;
+    return {
+      timestamp: new Date(
+        Date.parse(`${[year, month, day].join("-")}T${[hour, minute, second].join(":")}Z`),
+      ),
+      applicationId: appId,
+      userId: [userIdPart1, userIdPart2, userIdPart3, userIdPart4, userIdPart5].join("-"),
+    };
+  },
+};
+
 export type AccessInformation = {
   public?: {
     token: string;

tdrive/backend/node/src/services/documents/services/index.ts

@@ -13,7 +13,7 @@ import { PublicFile } from "../../../services/files/entities/file";
 import globalResolver from "../../../services/global-resolver";
 import { hasCompanyAdminLevel } from "../../../utils/company";
 import gr from "../../global-resolver";
-import { DriveFile, TYPE } from "../entities/drive-file";
+import { DriveFile, EditingSessionKeyFormat, TYPE } from "../entities/drive-file";
 import { FileVersion, TYPE as FileVersionType } from "../entities/file-version";
 import User, { TYPE as UserType } from "../../user/entities/user";
 
@@ -58,7 +58,6 @@ import {
 import archiver from "archiver";
 import internal from "stream";
 import config from "config";
-import { randomUUID } from "crypto";
 import { MultipartFile } from "@fastify/multipart";
 import { UploadOptions } from "src/services/files/types";
 
@@ -936,33 +935,18 @@ export class DocumentsService {
     editorApplicationId: string,
     context: DriveExecutionContext,
   ) => {
-    const isoUTCDateNoSpecialCharsNoMS = new Date()
-      .toISOString()
-      .replace(/\..+$/, "")
-      .replace(/[ZT:-]/g, "");
-    const newKey = [
-      isoUTCDateNoSpecialCharsNoMS,
-      editorApplicationId,
-      randomUUID().replace(/-+/g, ""),
-    ].join("-");
-    // OnlyOffice key limits: 128 chars, [0-9a-zA-z=_-]
-    // This is specific to it, but the constraint seems strict enough
-    // that any other system needing such a unique identifier would find
-    // this compatible. This value must be ensured to be the strictest
-    // common denominator to all plugin/interop systems. Plugins that
-    // require something even stricter have the option of maintaining
-    // a look up table to an acceptable value.
-    if (newKey.length > 128 || !/^[0-9a-zA-Z=_]+$/m.test(editorApplicationId))
-      CrudException.throwMe(
-        new Error('Invalid "editorApplicationId" string. Must be short and only alpha numeric'),
-        new CrudException("Invalid editorApplicationId", 400),
-      );
-
     if (!context) {
       this.logger.error("invalid execution context");
       return null;
     }
 
+    let newKey: string;
+    try {
+      newKey = EditingSessionKeyFormat.generate(editorApplicationId, context.user.id);
+    } catch (e) {
+      CrudException.throwMe(e, new CrudException("Error generating new editing_session_key", 500));
+    }
+
     const hasAccess = await checkAccess(id, null, "write", this.repository, context);
     if (!hasAccess) {
       logger.error("user does not have access drive item " + id);