低代码平台底层协议设计
1. 核心协议架构
1.1 协议分层设计
// 低代码平台协议栈
interface LowCodeProtocolStack {// 1. 传输层协议transport: TransportProtocol;// 2. 数据描述协议schema: SchemaProtocol;// 3. 组件描述协议component: ComponentProtocol;// 4. 行为描述协议action: ActionProtocol;// 5. 协作协议collaboration: CollaborationProtocol;
}
2. 传输层协议设计
2.1 增量更新协议
// 增量更新消息协议
interface DeltaUpdateProtocol {version: string; // 协议版本type: 'full' | 'delta'; // 全量/增量timestamp: number; // 时间戳sessionId: string; // 会话IDoperations: Operation[]; // 操作序列
}// 操作类型定义
interface Operation {id: string; // 操作IDtype: 'add' | 'update' | 'delete' | 'move';path: string; // JSON PatholdValue?: any; // 旧值（用于撤销）newValue?: any; // 新值components?: string[]; // 影响的组件
}// WebSocket 消息协议
interface WSMessage {cmd: string; // 命令类型seq: number; // 序列号payload: any; // 负载数据metadata: {userId: string;pageId: string;version: number;};
}// 命令类型枚举
enum WSCommand {SYNC_SCHEMA = 'sync_schema', // 同步SchemaOPERATION = 'operation', // 操作BROADCAST = 'broadcast', // 广播LOCK = 'lock', // 组件锁定SNAPSHOT = 'snapshot' // 快照
}
2.2 二进制传输协议
// Protocol Buffers 定义
syntax = "proto3";package lowcode;// 增量更新消息
message DeltaUpdate {string version = 1;int64 timestamp = 2;string session_id = 3;repeated Operation operations = 4;
}message Operation {string id = 1;OperationType type = 2;string path = 3;bytes old_value = 4; // 使用bytes存储任意数据bytes new_value = 5;repeated string components = 6;
}enum OperationType {ADD = 0;UPDATE = 1;DELETE = 2;MOVE = 3;
}// 二进制Schema表示
message BinarySchema {map<string, Component> components = 1;map<string, DataSource> data_sources = 2;repeated Event events = 3;Layout layout = 4;
}message Component {string id = 1;string type = 2;bytes props = 3; // 序列化的属性repeated Component children = 4;
}
3. Schema 描述协议
3.1 核心Schema协议
{"$schema": "https://lowcode.dev/schema/v1.json","version": "1.0.0","metadata": {"name": "用户管理页面","description": "用户列表和操作页面","author": "developer@company.com","createdAt": "2024-01-01T00:00:00Z","updatedAt": "2024-01-01T00:00:00Z"},"dataSchema": {"definitions": {"User": {"type": "object","properties": {"id": { "type": "string" },"name": { "type": "string" },"email": { "type": "string" },"status": { "type": "string", "enum": ["active", "inactive"] }}}}},"pageSchema": {"layout": {"type": "grid","columns": 24,"gutter": 8},"components": [{"id": "user_table","type": "Table","version": "1.0.0","binding": {"data": "{{dataSource.userList}}","pagination": "{{pagination}}"},"constraints": {"minWidth": 6,"maxWidth": 24,"resizable": true,"draggable": true}}]}
}
3.2 扩展Schema协议
// 类型化的Schema协议
interface LowCodeSchema {// 元数据meta: SchemaMeta;// 数据定义data: DataSchema;// 页面结构page: PageSchema;// 行为定义actions: ActionSchema;// 权限控制permissions: PermissionSchema;// 主题样式theme: ThemeSchema;
}// 数据Schema协议
interface DataSchema {sources: {[key: string]: DataSourceConfig;};models: {[key: string]: DataModel;};relationships: DataRelationship[];
}// 数据源配置协议
interface DataSourceConfig {type: 'rest' | 'graphql' | 'websocket' | 'localStorage';endpoint: string;method?: string;headers?: Record<string, string>;pollingInterval?: number;autoRefresh?: boolean;transform?: string; // JS转换函数
}// 数据模型协议
interface DataModel {fields: {[key: string]: FieldDefinition;};indexes?: string[];validation?: ValidationRule[];
}interface FieldDefinition {type: FieldType;required?: boolean;defaultValue?: any;validation?: ValidationRule;computed?: string; // 计算字段表达式
}
4. 组件描述协议
4.1 组件元数据协议
# 组件描述文件 (component.yaml)
component:name: "DataTable"version: "1.2.0"category: "data"description: "数据表格组件"# 组件能力声明capabilities:- "sortable"- "filterable" - "paginate"- "selectable"# 属性协议props:- name: "dataSource"type: "DataSource"required: truedescription: "数据源配置"- name: "columns"type: "Column[]"required: trueschema:type: "array"items:type: "object"properties:title: { type: "string" }dataIndex: { type: "string" }width: { type: "number" }# 事件协议events:- name: "rowClick"payload:rowData: "object"rowIndex: "number"- name: "selectionChange"payload:selectedRows: "object[]"# 方法协议methods:- name: "reload"description: "重新加载数据"- name: "setPagination"parameters:page: "number"pageSize: "number"# 样式协议styles:cssVariables:- "--table-header-bg"- "--table-row-hover-bg"className: "lowcode-data-table"# 依赖声明dependencies:- "axios@^1.0.0"- "lodash@^4.0.0"# 兼容性compatibility:frameworks:- "vue@^3.0.0"- "react@^18.0.0"platforms:- "web"- "mobile"
4.2 组件通信协议
// 组件间通信协议
interface ComponentCommunicationProtocol {// 事件总线协议events: {publish<T>(topic: string, data: T): void;subscribe<T>(topic: string, handler: (data: T) => void): Unsubscribe;};// 数据流协议dataFlow: {inputs: {[key: string]: DataBinding;};outputs: {[key: string]: EventBinding;};};// 方法调用协议methods: {call(componentId: string, method: string, args: any[]): Promise<any>;expose(methods: { [key: string]: Function }): void;};
}// 数据绑定协议
interface DataBinding {type: 'oneWay' | 'twoWay';source: string; // 数据源路径transform?: string; // 数据转换函数validator?: string; // 数据验证函数
}// 组件插槽协议
interface SlotProtocol {name: string;description: string;allowedComponents: string[]; // 允许放置的组件类型maxChildren?: number;layout?: 'vertical' | 'horizontal' | 'free';
}
5. 行为描述协议
5.1 动作链协议
// 行为描述协议
interface ActionProtocol {version: string;actions: ActionDefinition[];conditions?: ConditionDefinition[];variables?: VariableDefinition[];
}// 动作定义
interface ActionDefinition {id: string;name: string;trigger: Trigger;conditions?: string[]; // 条件ID列表steps: ActionStep[];errorHandling?: ErrorHandling;
}// 动作步骤
interface ActionStep {type: 'api' | 'data' | 'ui' | 'custom';name: string;config: StepConfig;next?: string; // 下一步动作IDtimeout?: number;retry?: RetryConfig;
}// API动作协议
interface ApiActionConfig {method: string;url: string;headers?: Record<string, string>;params?: any;data?: any;onSuccess?: string; // 成功后的动作onError?: string; // 失败后的动作
}// 数据动作协议
interface DataActionConfig {operation: 'set' | 'get' | 'update' | 'delete';target: string; // 数据路径value?: any;expression?: string; // 计算表达式
}
5.2 条件表达式协议
// 条件表达式协议
interface ConditionProtocol {// 逻辑表达式expression: string;// 或使用声明式条件conditions?: ConditionGroup;
}interface ConditionGroup {operator: 'and' | 'or';conditions: (SingleCondition | ConditionGroup)[];
}interface SingleCondition {left: string; // 左操作数operator: ConditionOperator;right: any; // 右操作数
}type ConditionOperator = | 'eq' | 'neq' | 'gt' | 'gte' | 'lt' | 'lte'| 'contains' | 'startsWith' | 'endsWith'| 'in' | 'notIn' | 'isEmpty' | 'isNotEmpty';
6. 协作协议
6.1 实时协作协议
// 操作转换协议 (Operational Transformation)
interface OTOperation {id: string;userId: string;timestamp: number;baseVersion: number;operations: Operation[];metadata: {cursorPosition?: CursorPosition;selection?: SelectionRange;};
}// 冲突解决协议
interface ConflictResolution {strategy: 'lastWriteWin' | 'manual' | 'custom';resolver?: string; // 自定义解决函数
}// 锁定协议
interface LockProtocol {componentId: string;userId: string;timestamp: number;type: 'exclusive' | 'shared';expiresIn: number; // 锁过期时间
}// 版本控制协议
interface VersionControl {current: number;history: VersionSnapshot[];branches?: BranchInfo[];
}interface VersionSnapshot {version: number;timestamp: number;author: string;description: string;checksum: string;operations: Operation[];
}
7. 扩展协议
7.1 插件协议
// 插件系统协议
interface PluginProtocol {// 插件描述manifest: PluginManifest;// 生命周期lifecycle: {install(context: PluginContext): void;activate(context: PluginContext): void;deactivate(): void;uninstall(): void;};// 扩展点extensionPoints: {components?: ComponentExtension[];actions?: ActionExtension[];dataSources?: DataSourceExtension[];validators?: ValidatorExtension[];};
}// 插件清单
interface PluginManifest {id: string;name: string;version: string;description: string;author: string;dependencies?: string[];compatibility: string;permissions: string[];
}
7.2 主题协议
// 主题描述协议
interface ThemeProtocol {name: string;version: string;tokens: DesignTokens;components: ComponentThemes;breakpoints: Breakpoints;
}interface DesignTokens {colors: {primary: string;secondary: string;success: string;warning: string;error: string;[key: string]: string;};spacing: {xs: string;sm: string;md: string;lg: string;xl: string;};typography: {fontFamily: string;fontSize: {sm: string;md: string;lg: string;};};
}
8. 性能优化协议
8.1 懒加载协议
// 资源懒加载协议
interface LazyLoadProtocol {components: {[componentId: string]: ComponentLoadConfig;};data: {[dataSourceId: string]: DataLoadConfig;};
}interface ComponentLoadConfig {priority: 'high' | 'medium' | 'low';conditions?: string[]; // 加载条件placeholder?: string; // 占位组件
}// 缓存协议
interface CacheProtocol {strategy: 'memory' | 'localStorage' | 'indexedDB';ttl: number; // 缓存时间maxSize?: number;invalidateOn?: string[]; // 失效条件
}
9. 安全协议
9.1 权限控制协议
// 权限描述协议
interface PermissionProtocol {roles: RoleDefinition[];policies: Policy[];resources: Resource[];
}interface RoleDefinition {name: string;permissions: string[];inherits?: string[];
}interface Policy {effect: 'allow' | 'deny';actions: string[];resources: string[];conditions?: ConditionGroup;
}// 数据安全协议
interface DataSecurity {encryption: {algorithm: string;key: string;};masking: {fields: string[];strategy: 'partial' | 'full' | 'hash';};audit: {enabled: boolean;logOperations: boolean;};
}
10. 协议版本管理
10.1 版本协商协议
// 版本协商
interface VersionNegotiation {clientVersion: string;supportedVersions: string[];fallbackVersion?: string;
}// 协议升级
interface ProtocolUpgrade {fromVersion: string;toVersion: string;migrationScript?: string;breakingChanges: string[];deprecated: string[];
}
这种底层协议设计提供了：
- 标准化：统一的组件、数据、行为描述
- 可扩展性：支持插件和自定义协议
- 高性能：增量更新、二进制传输
- 协作能力：实时协作和冲突解决
- 安全性：完整的权限和数据安全控制
- 兼容性：版本管理和迁移支持
这些协议构成了低代码平台的"语言"，使得不同模块能够高效协作，支持复杂的应用场景。
