Extension Database

Store your data in whatever data store you already have with the generic database extension. It takes a Promise to fetch data and another Promise to store the data, that’s all. Hocuspocus will handle the rest.

#Installation

Install the database extension like this:

npm install @hocuspocus/extension-database

#Configuration

fetch

Expects an async function (or Promise) which returns a Y.js compatible Uint8Array (or null). Make sure to return the same Uint8Array that was saved in store(), and do not create a new Ydoc, as doing so would lead to a new history (and duplicated content).

If you want to initially create a Ydoc based off raw text/json, you can do so here using a transformer of your choice (e.g. TiptapTransformer.toYdoc, or ProsemirrorTransformer.toYdoc)

store

Expects an async function (or Promise) which persists the Y.js binary data somewhere.

#Usage

The following example uses SQLite to store and retrieve data. You can replace that part with whatever data store you have. As long as you return a Promise you can store data with PostgreSQL, MySQL, MongoDB, S3 … If you actually want to use SQLite, you can have a look at the SQLite extension.

import { Server } from "@hocuspocus/server";
import { Database } from "@hocuspocus/extension-database";
import sqlite3 from "sqlite3";

const server = new Server({
  extensions: [
    new Database({
      // Return a Promise to retrieve data …
      fetch: async ({ documentName }) => {
        return new Promise((resolve, reject) => {
          this.db?.get(
            `
            SELECT data FROM "documents" WHERE name = $name ORDER BY rowid DESC
          `,
            {
              $name: documentName,
            },
            (error, row) => {
              if (error) {
                reject(error);
              }

              resolve(row?.data);
            }
          );
        });
      },
      // … and a Promise to store data:
      store: async ({ documentName, state }) => {
        this.db?.run(
          `
          INSERT INTO "documents" ("name", "data") VALUES ($name, $data)
            ON CONFLICT(name) DO UPDATE SET data = $data
        `,
          {
            $name: documentName,
            $data: state,
          }
        );
      },
    }),
  ],
});

server.listen();