在协同编辑场景中,数据的实时同步与持久化是系统稳定性的核心。SpreadJS 作为一款前端 Excel 表格控件,通过协同服务,可以支持多人同时在线编辑表格。然而,仅有内存级的同步并不足以满足企业级应用需求:如果服务器重启、内存溢出或用户需要回溯历史操作,数据极有可能丢失或无法查询。
为了解决这一问题,SpreadJS 在服务器端提供了 数据库适配器(IDatabaseAdapter) 机制。数据库适配器负责将协同编辑产生的 文档快照(snapshot) 和 操作流(operations,简称 op) 与持久化存储系统对接。这样,系统不仅能够保存文档的最新状态,还能完整追溯历史操作,支持版本回滚和数据分析。
目前官方内置了 MemoryDb、Postgres、Sqlite3 等适配器,但在实际业务系统中,MySQL 依旧是最常见、最稳定的企业级数据库之一。因此,本文将介绍如何基于 SpreadJS 的数据库适配器接口,实现 MySQL 适配器,并将其集成到 DocumentServices 中,从而满足以下典型业务场景:
数据安全与持久化:文档快照和操作日志实时写入 MySQL,避免因服务器故障导致数据丢失。
版本与历史查询:通过操作记录,可以回放或还原文档到任意历史时间点,满足审计和合规需求。
横向扩展与系统集成:依托 MySQL 的事务、索引和集群能力,协同服务可以更好地与现有企业系统集成。
通过 MySQL 数据库适配的支持,企业能够在 SpreadJS 协同服务中获得更高的 稳定性、可扩展性和业务适配性,从而真正将前端在线表格能力与后端数据管理体系打通。
具体实现如下:
参考建表SQL,包含了里程碑数据库
CREATE TABLE IF NOT EXISTS documents(
id VARCHAR(255) PRIMARY KEY,
type VARCHAR(255) NOT NULL,
version INT NOT NULL,
snapshot_version INT NOT NULL
);
CREATE TABLE IF NOT EXISTS operations(
doc_id VARCHAR(255) NOT NULL,
version INT NOT NULL,
operation TEXT NOT NULL,
PRIMARY KEY(doc_id, version),
FOREIGN KEY(doc_id) REFERENCES documents(id) ON DELETE CASCADE
);
CREATE TABLE IF NOT EXISTS snapshot_fragments(
doc_id VARCHAR(255) NOT NULL,
fragment_id VARCHAR(255) NOT NULL,
data TEXT NOT NULL,
PRIMARY KEY(doc_id, fragment_id),
FOREIGN KEY(doc_id) REFERENCES documents(id) ON DELETE CASCADE
);
CREATE TABLE IF NOT EXISTS milestone_snapshot(
doc_id VARCHAR(255) NOT NULL,
version INT NOT NULL,
snapshot TEXT NOT NULL,
PRIMARY KEY(doc_id, version),
FOREIGN KEY(doc_id) REFERENCES documents(id) ON DELETE CASCADE
);
列名并不限制规则,在后面适配器实现的时候做好对应即可。
如果有其他信息需要存储,可以新建表,在DocumentServices中使用中间件或者钩子函数来写其他信息。
适配器参考实现,关于mySql数据库连接和SQL执行方式可以按照项目需求自定义修改。
export class MySQLDb extends Db {
constructor(pool) {
super();
this.pool = pool;
}
async getDocument(docId) {
console.log("Fetching document:", docId);
const connection = await this.pool.getConnection();
const [rows] = await connection.execute(
'SELECT * FROM documents WHERE id = ?',
[docId]
);
console.log("Fetched document rows:", rows);
connection.release();
if (0 === rows.length) return;
const row = rows[0];
return {
id: row.id,
type: row.type,
version: row.version,
snapshotVersion: row.snapshot_version
};
}
async getSnapshot(docId) {
console.log("Fetching snapshot for document:", docId);
const connection = await this.pool.getConnection();
const [rows] = await connection.execute(
'SELECT * FROM documents WHERE id = ?',
[docId]
);
connection.release();
console.log("Fetched snapshot rows:", rows);
if (0 === rows.length) return;
const row = rows[0];
const fragments = await this.getFragments(docId);
return {
id: row.id,
v: row.snapshot_version,
type: row.type,
fragments: fragments
};
}
async getFragments(docId) {
console.log("Fetching fragments for document:", docId);
const connection = await this.pool.getConnection();
const [rows] = await connection.execute(
'SELECT fragment_id, data FROM snapshot_fragments WHERE doc_id = ?',
[docId]
);
console.log("Fetched fragments rows:", rows);
connection.release();
const fragments = {};
for (const row of rows) {
fragments[row.fragment_id] = JSON.parse(row.data);
}
return fragments;
}
async getFragment(docId, fragmentId) {
console.log("Fetching fragment:", docId, fragmentId);
const connection = await this.pool.getConnection();
const [rows] = await connection.execute(
'SELECT data FROM snapshot_fragments WHERE doc_id = ? AND fragment_id = ?',
[docId, fragmentId]
);
connection.release();
console.log("Fetched fragment rows:", rows);
if (0 === rows.length) return;
return JSON.parse(rows[0].data);
}
async getOps(docId, from, to) {
console.log("Fetching operations for document:", docId, "from version:", from, "to version:", to);
const connection = await this.pool.getConnection();
const [rows] = await connection.execute(
'SELECT operation FROM operations WHERE doc_id = ? AND version >= ?' + (to ? ' AND version <= ?' : '') + " ORDER BY version",
to ? [docId, from, to] : [docId, from]
);
connection.release();
console.log("Fetched operations rows:", rows);
if (0 === rows.length) return [];
return rows.map(row => JSON.parse(row.operation));
}
async commitOp(docId, op, document) {
console.log("Committing operation:", docId, op, document);
const connection = await this.pool.getConnection();
try {
connection.beginTransaction();
// query version from document db
const [rows] = await connection.execute(
'SELECT version FROM documents WHERE id = ?',
[docId]
);
if (op.create) {
console.log("Creating new document:", docId, rows);
if (rows.length > 0) {
await connection.rollback();
return false;
}
await connection.execute(
'INSERT INTO documents (id, type, version, snapshot_version) VALUES (?, ?, ?, ?)',
[docId, document.type, document.version, document.snapshotVersion]
);
await connection.execute(
'INSERT INTO operations (doc_id, version, operation) VALUES (?, ?, ?)',
[docId, op.v, JSON.stringify(op)]
);
await connection.commit();
console.log("Operation create successfully.");
return true;
}
else if (op.del) {
console.log("Deleting document:", docId, rows);
if (rows.length === 0) {
await connection.rollback();
return false;
}
await connection.execute(
'DELETE FROM documents WHERE id = ?',
[docId]
);
await connection.commit();
console.log("Operation delete successfully.");
return true;
}
else {
console.log("Updating operation:", docId, op, rows);
if (rows.length === 0 || rows[0].version !== op.v) {
await connection.rollback();
return false;
}
await connection.execute(
'INSERT INTO operations (doc_id, version, operation) VALUES (?, ?, ?)',
[docId, op.v, JSON.stringify(op)]
);
await connection.execute(
'UPDATE documents SET version = ? WHERE id = ?',
[document.version, docId]
);
await connection.commit();
console.log("Operation update successfully.");
return true;
}
} catch (error) {
console.error('Error committing operation:', error);
await connection.rollback();
return false;
}
finally {
connection.release();
}
}
async commitSnapshot(docId, snapshot) {
console.log("Committing snapshot for document:", docId, snapshot);
const connection = await this.pool.getConnection();
try {
connection.beginTransaction();
// query snapshot_version from document db
const [rows] = await connection.execute(
'SELECT snapshot_version FROM documents WHERE id = ?',
[docId]
);
if (0 === rows.length) {
await connection.rollback();
return false;
}
const currentSnapshotVersion = rows[0].snapshot_version;
if (snapshot.fromVersion !== currentSnapshotVersion || snapshot.v <= currentSnapshotVersion) {
await connection.rollback();
return false;
}
await connection.execute(
'UPDATE documents SET snapshot_version = ? WHERE id = ?',
[snapshot.v, docId]
);
if (snapshot.fragmentsChanges.deleteSnapshot) {
await connection.execute(
'DELETE FROM snapshot_fragments WHERE doc_id = ?',
[docId]
);
} else {
const { createFragments, updateFragments, deleteFragments } = snapshot.fragmentsChanges;
console.log("Committing snapshot fragments changes:", createFragments, updateFragments, deleteFragments);
if (createFragments) {
for (const [fragmentId, data] of Object.entries(createFragments)) {
await connection.execute(
'INSERT INTO snapshot_fragments (doc_id, fragment_id, data) VALUES (?, ?, ?)',
[docId, fragmentId, JSON.stringify(data)]
);
}
}
if (updateFragments) {
for (const [fragmentId, data] of Object.entries(updateFragments)) {
await connection.execute(
'UPDATE snapshot_fragments SET data = ? WHERE doc_id = ? AND fragment_id = ?',
[JSON.stringify(data), docId, fragmentId]
);
}
}
if (deleteFragments) {
for (const fragmentId of deleteFragments) {
await connection.execute(
'DELETE FROM snapshot_fragments WHERE doc_id = ? AND fragment_id = ?',
[docId, fragmentId]
);
}
}
}
await connection.commit();
return true;
} catch (error) {
console.error('Error committing snapshot:', error);
await connection.rollback();
return false;
} finally {
connection.release();
}
}
async close() {
await this.pool.end();
}
}
里程碑数据库适配参考实现
export class MySQLMilestoneDb {
constructor(pool, interval) {
this.pool = pool;
if(interval){
this.interval = interval; // Interval in seconds for saving milestones
}
}
async saveMilestoneSnapshot(snapshot) {
console.log("Saving milestone snapshot:", snapshot);
const connection = await this.pool.getConnection();
try {
await connection.beginTransaction();
await connection.execute(
'INSERT INTO milestone_snapshot (doc_id, version, snapshot) VALUES (?, ?, ?)',
[snapshot.id, snapshot.v, JSON.stringify(snapshot)]
);
await connection.commit();
console.log("Milestone snapshot saved successfully.");
return true;
} catch (error) {
console.error('Error saving milestone snapshot:', error);
await connection.rollback();
return false;
} finally {
connection.release();
}
}
async getMilestoneSnapshot(id, version) {
console.log("Fetching milestone snapshot for document:", id, "version:", version);
const connection = await this.pool.getConnection();
const [rows] = await connection.execute(
'SELECT * FROM milestone_snapshot WHERE doc_id = ? AND version <= ? ORDER BY version DESC LIMIT 1',
[id, version]
);
connection.release();
console.log("Fetched milestone snapshot rows:", rows);
if (0 === rows.length) return;
const row = rows[0];
return JSON.parse(row.snapshot);
}
}
在DocumentServices中配置db和milestoneDb
const mySqlAdapter = new MySQLDb(mySqlPool);
const MySQLMilestoneAdapter = new MySQLMilestoneDb(mySqlPool, 100);
const documentServices = new OT.DocumentServices({
db: mySqlAdapter,
milestoneDb: MySQLMilestoneAdapter
});
server.useFeature(OT.documentFeature(documentServices));
以上便是SpreadJS 协同服务MySQL数据库适配实现。
SpreadJS | 下载试用
纯前端表格控件SpreadJS,兼容 450 种以上的 Excel 公式,具备“高性能、跨平台、与 Excel 高度兼容”的产品特性,备受华为、苏宁易购、天弘基金等行业龙头企业的青睐,并被中国软件行业协会认定为“中国优秀软件产品”。SpreadJS 可为用户提供类 Excel 的功能,满足表格文档协同编辑、 数据填报、 类 Excel 报表设计等业务场景需求,极大的降低企业研发成本和项目交付风险。
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