fix(sync): push local changes on reconnect

When an editing session is interrupted steps that were already pushed to the server may be cleared alongside the sync service session. Make sure to push all local state that is not part of the document state when (re-)connecting. Tests Yjs relies on a browser environment. Therefore we test it in a cypress test. Move these tests into component tests to separate them from 'normal' e2e tests. Signed-off-by: Max <[email protected]>
nextcloud · mejo- · Jan 29, 2024 · Jan 17, 2024 · Jan 18, 2024 · Jan 18, 2024
commit 456f218414f8b67e6ef542947293c0d8e51dc7a5
diff --git a/cypress.config.js b/cypress.config.js
@@ -31,6 +31,12 @@ module.exports = defineConfig({
 		experimentalSessionAndOrigin: true,
 		specPattern: 'cypress/e2e/**/*.{js,jsx,ts,tsx}',
 	},
+	component: {
+		devServer: {
+			framework: "vue",
+			bundler: "webpack",
+		},
+	},
 	retries: {
 		runMode: 2,
 		// do not retry in `cypress open`

diff --git a/cypress/component/helpers/yjs.cy.js b/cypress/component/helpers/yjs.cy.js
@@ -0,0 +1,77 @@
+/*
+ * @copyright Copyright (c) 2023 Jonas <[email protected]>
+ *
+ * @author Jonas <[email protected]>
+ *
+ * @license AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+import * as Y from 'yjs'
+import { getDocumentState, getUpdateMessage, applyUpdateMessage } from '../../../src/helpers/yjs.js'
+
+describe('Yjs base64 wrapped with our helpers', function() {
+	it('applies step in wrong order', function() {
+		const source = new Y.Doc()
+		const target = new Y.Doc()
+		const sourceMap = source.getMap()
+		const targetMap = target.getMap()
+
+		target.on('afterTransaction', (tr, doc) => {
+			// console.log('afterTransaction', tr)
+		})
+
+		const state0 = getDocumentState(source)
+
+		// Add keyA to source and apply to target
+		sourceMap.set('keyA', 'valueA')
+
+		const stateA = getDocumentState(source)
+		const update0A = getUpdateMessage(source, state0)
+		applyUpdateMessage(target, update0A)
+		expect(targetMap.get('keyA')).to.be.eq('valueA')
+
+		// Add keyB to source, don't apply to target yet
+		sourceMap.set('keyB', 'valueB')
+		const stateB = getDocumentState(source)
+		const updateAB = getUpdateMessage(source, stateA)
+
+		// Add keyC to source, apply to target
+		sourceMap.set('keyC', 'valueC')
+		const updateBC = getUpdateMessage(source, stateB)
+		applyUpdateMessage(target, updateBC)
+		expect(targetMap.get('keyB')).to.be.eq(undefined)
+		expect(targetMap.get('keyC')).to.be.eq(undefined)
+
+		// Apply keyB to target
+		applyUpdateMessage(target, updateAB)
+		expect(targetMap.get('keyB')).to.be.eq('valueB')
+		expect(targetMap.get('keyC')).to.be.eq('valueC')
+	})
+
+	it('update message is empty if no additional state exists', function() {
+		const source = new Y.Doc()
+		const sourceMap = source.getMap()
+		const state0 = getDocumentState(source)
+		sourceMap.set('keyA', 'valueA')
+		const stateA = getDocumentState(source)
+		const update0A = getUpdateMessage(source, state0)
+		const updateAA = getUpdateMessage(source, stateA)
+		expect(update0A.length).to.be.eq(40)
+		expect(updateAA).to.be.eq(undefined)
+	})
+
+})
diff --git a/cypress/e2e/api/Yjs.spec.js → cypress/component/upstream/Yjs.cy.js b/cypress/e2e/api/Yjs.spec.js → cypress/component/upstream/Yjs.cy.js
diff --git a/cypress/support/component-index.html b/cypress/support/component-index.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width,initial-scale=1.0">
+    <title>Components App</title>
+  </head>
+  <body>
+    <div data-cy-root></div>
+  </body>
+</html>
diff --git a/cypress/support/component.js b/cypress/support/component.js
@@ -0,0 +1,27 @@
+// ***********************************************************
+// This example support/component.js is processed and
+// loaded automatically before your test files.
+//
+// This is a great place to put global configuration and
+// behavior that modifies Cypress.
+//
+// You can change the location of this file or turn off
+// automatically serving support files with the
+// 'supportFile' configuration option.
+//
+// You can read more here:
+// https://on.cypress.io/configuration
+// ***********************************************************
+
+// Import commands.js using ES2015 syntax:
+import './commands.js'
+
+// Alternatively you can use CommonJS syntax:
+// require('./commands')
+
+import { mount } from 'cypress/vue2'
+
+Cypress.Commands.add('mount', mount)
+
+// Example use:
+// cy.mount(MyComponent)
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -104,6 +104,7 @@
     "vue-click-outside": "^1.1.0",
     "vue-material-design-icons": "^5.2.0",
     "vuex": "^3.6.2",
+    "y-protocols": "^1.0.6",
     "y-websocket": "^1.5.1",
     "yjs": "^13.6.10"
   },

diff --git a/src/components/Editor.vue b/src/components/Editor.vue
@@ -102,7 +102,7 @@ import {
 import ReadonlyBar from './Menu/ReadonlyBar.vue'
 
 import { logger } from '../helpers/logger.js'
-import { getDocumentState, applyDocumentState } from '../helpers/yjs.js'
+import { getDocumentState, applyDocumentState, getUpdateMessage } from '../helpers/yjs.js'
 import { SyncService, ERROR_TYPE, IDLE_TIMEOUT } from './../services/SyncService.js'
 import createSyncServiceProvider from './../services/SyncServiceProvider.js'
 import AttachmentResolver from './../services/AttachmentResolver.js'
@@ -481,6 +481,11 @@ export default {
 		onLoaded({ documentSource, documentState }) {
 			if (documentState) {
 				applyDocumentState(this.$ydoc, documentState, this.$providers[0])
+				// distribute additional state that may exist locally
+				const updateMessage = getUpdateMessage(this.$ydoc, documentState)
+				if (updateMessage) {
+					this.$queue.push(updateMessage)
+				}
 			}
 
 			this.hasConnectionIssue = false

diff --git a/src/helpers/yjs.js b/src/helpers/yjs.js
@@ -24,21 +24,71 @@ import { encodeArrayBuffer, decodeArrayBuffer } from '../helpers/base64.js'
 import { Doc, encodeStateAsUpdate, applyUpdate } from 'yjs'
 
 /**
+ * Get Document state encode as base64.
  *
- * @param {Doc} ydoc - encode state of this doc
+ * Used to store yjs state on the server.
+ * @param {Y.Doc} ydoc - encode state of this doc
  */
 export function getDocumentState(ydoc) {
-	const update = encodeStateAsUpdate(ydoc)
+	const update = Y.encodeStateAsUpdate(ydoc)
 	return encodeArrayBuffer(update)
 }
 
 /**
  *
- * @param {Doc} ydoc - apply state to this doc
+ * @param {Y.Doc} ydoc - apply state to this doc
  * @param {string} documentState - base64 encoded doc state
  * @param {object} origin - initiator object e.g. WebsocketProvider
  */
 export function applyDocumentState(ydoc, documentState, origin) {
 	const update = decodeArrayBuffer(documentState)
-	applyUpdate(ydoc, update, origin)
+	Y.applyUpdate(ydoc, update, origin)
+}
+
+/**
+ * Update message for everything in ydoc that is not in encodedBaseUpdate
+ *
+ * @param {Y.Doc} ydoc - encode state of this doc
+ * @param {string} encodedBaseUpdate - base64 encoded doc update to build upon
+ */
+export function getUpdateMessage(ydoc, encodedBaseUpdate) {
+	const baseUpdate = decodeArrayBuffer(encodedBaseUpdate)
+	const baseStateVector = Y.encodeStateVectorFromUpdate(baseUpdate)
+	const docStateVector = Y.encodeStateVector(ydoc)
+	if (sameState(baseStateVector, docStateVector)) {
+		// no additional state in the ydoc - early return
+		return
+	}
+	const encoder = encoding.createEncoder()
+	encoding.writeVarUint(encoder, messageSync)
+	const update = Y.encodeStateAsUpdate(ydoc, baseStateVector)
+	syncProtocol.writeUpdate(encoder, update)
+	const buf = encoding.toUint8Array(encoder)
+	return encodeArrayBuffer(buf)
+}
+
+/**
+ * Apply an updated message to the ydoc.
+ *
+ * Only used in tests right now.
+ * @param {Y.Doc} ydoc - encode state of this doc
+ * @param {string} updateMessage - base64 encoded y-websocket sync message with update
+ * @param {object} origin - initiator object e.g. WebsocketProvider
+ */
+export function applyUpdateMessage(ydoc, updateMessage, origin = 'origin') {
+	const updateBuffer = decodeArrayBuffer(updateMessage)
+	const decoder = decoding.createDecoder(updateBuffer)
+	const messageType = decoding.readVarUint(decoder)
+	if (messageType !== messageSync) {
+		console.error('y.js update message with invalid type', messageType)
+		return
+	}
+	// There are no responses to updates - so this is a dummy.
+	const encoder = encoding.createEncoder()
+	syncProtocol.readSyncMessage(
+		decoder,
+		encoder,
+		ydoc,
+		origin,
+	)
 }