collaborative editor - wip

server/src/collaboration/extensions/persistence.extension.ts

@@ -0,0 +1,59 @@
+import { Extension, onLoadDocumentPayload, onStoreDocumentPayload } from '@hocuspocus/server';
+import * as Y from 'yjs';
+import { PageService } from '../../core/page/page.service';
+import { Injectable } from '@nestjs/common';
+import { TiptapTransformer } from '@hocuspocus/transformer';
+
+@Injectable()
+export class PersistenceExtension implements Extension {
+  constructor(private readonly pageService: PageService) {}
+
+  async onLoadDocument(data: onLoadDocumentPayload) {
+    const { documentName, document } = data;
+
+    if (!document.isEmpty('default')) {
+      return;
+    }
+
+    const page = await this.pageService.findById(documentName);
+
+    if (!page) {
+      console.log('page does not exist.');
+      //TODO: terminate connection if the page does not exist?
+      return;
+    }
+
+    if (page.ydoc) {
+      const doc = new Y.Doc();
+      const dbState = new Uint8Array(page.ydoc);
+
+      Y.applyUpdate(doc, dbState);
+      return doc;
+    }
+
+    // if no ydoc state in db convert json in page.content to Ydoc.
+    const ydoc = TiptapTransformer.toYdoc(page.content, 'default');
+
+    Y.encodeStateAsUpdate(ydoc);
+    return ydoc;
+  }
+
+  async onStoreDocument(data: onStoreDocumentPayload) {
+    const { documentName, document, context } = data;
+
+    const pageId = documentName;
+
+    const tiptapJson = TiptapTransformer.fromYdoc(document, 'default');
+    const ydocState = Buffer.from(Y.encodeStateAsUpdate(document));
+
+    try {
+      await this.pageService.updateState(
+        pageId,
+        tiptapJson,
+        ydocState,
+      );
+    } catch (err) {
+      console.error(`Failed to update page ${documentName}`);
+    }
+  }
+}