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场景介绍

IPC/RPC的主要工作是让运行在不同进程的Proxy和Stub互相通信,包括Proxy和Stub运行在不同设备的情况。

开发步骤

ArkTS侧开发步骤

说明

  • 此文档中的示例代码描述的是系统应用跨进程通信。

  • 当前不支持三方应用实现ServiceExtensionAbility,三方应用的UIAbility组件可以通过Context连接系统提供的ServiceExtensionAbility。

  • 当前使用场景: 仅限客户端是三方应用,服务端是系统应用。

  1. 添加依赖

     // FA模型需要从@kit.AbilityKit导入featureAbility
     // import { featureAbility } from '@kit.AbilityKit';
     import { rpc } from '@kit.IPCKit';
  2. 绑定Ability

    首先,构造变量want,指定要绑定的Ability所在应用的包名、组件名,如果是跨设备的场景,还需要绑定目标设备NetworkId(组网场景下对应设备的标识符,可以使用distributedDeviceManager获取目标设备的NetworkId);然后,构造变量connect,指定绑定成功、绑定失败、断开连接时的回调函数;最后,FA模型使用featureAbility提供的接口绑定Ability,Stage模型通过context获取服务后用提供的接口绑定Ability。

     // FA模型需要从@kit.AbilityKit导入featureAbility
     // import { featureAbility } from "@kit.AbilityKit";
     import { Want, common } from '@kit.AbilityKit';
     import { rpc } from '@kit.IPCKit';
     import { hilog } from '@kit.PerformanceAnalysisKit';
     import { distributedDeviceManager } from '@kit.DistributedServiceKit';
     import { BusinessError } from '@kit.BasicServicesKit';
    
     let dmInstance: distributedDeviceManager.DeviceManager | undefined;
     let proxy: rpc.IRemoteObject | undefined;
     let connectId: number;
    
     // 单个设备绑定Ability
     let want: Want = {
       // 包名和组件名写实际的值
       bundleName: "ohos.rpc.test.server",
       abilityName: "ohos.rpc.test.server.ServiceAbility",
     };
     let connect: common.ConnectOptions = {
       onConnect: (elementName, remoteProxy) => {
         hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
         proxy = remoteProxy;
       },
       onDisconnect: (elementName) => {
         hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
       },
       onFailed: () => {
         hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
       }
     };
     // FA模型使用此方法连接服务
     // connectId = featureAbility.connectAbility(want, connect);
    
     let context: common.UIAbilityContext = getContext(this) as common.UIAbilityContext; // UIAbilityContext
     // 建立连接后返回的Id需要保存下来,在解绑服务时需要作为参数传入
     connectId = context.connectServiceExtensionAbility(want,connect);
    
     // 跨设备绑定
     try{
       dmInstance = distributedDeviceManager.createDeviceManager("ohos.rpc.test");
     } catch(error) {
       let err: BusinessError = error as BusinessError;
       hilog.error(0x0000, 'testTag', 'createDeviceManager errCode:' + err.code + ', errMessage:' + err.message);
     }
    
     // 使用distributedDeviceManager获取目标设备NetworkId
     if (dmInstance != undefined) {
       let deviceList = dmInstance.getAvailableDeviceListSync();
       let networkId = deviceList[0].networkId;
       let want: Want = {
         bundleName: "ohos.rpc.test.server",
         abilityName: "ohos.rpc.test.service.ServiceAbility",
         deviceId: networkId,
         flags: 256
       };
       // 建立连接后返回的Id需要保存下来,在断开连接时需要作为参数传入
       // FA模型使用此方法连接服务
       // connectId = featureAbility.connectAbility(want, connect);
    
       // 第一个参数是本应用的包名,第二个参数是接收distributedDeviceManager的回调函数
       connectId = context.connectServiceExtensionAbility(want,connect);
     }
  3. 服务端处理客户端请求

    服务端被绑定的Ability在onConnect方法里返回继承自rpc.RemoteObject的对象,该对象需要实现onRemoteMessageRequest方法,处理客户端的请求。

     import { rpc } from '@kit.IPCKit';
     import { Want } from '@kit.AbilityKit';
     class Stub extends rpc.RemoteObject {
       constructor(descriptor: string) {
         super(descriptor);
       }
       onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
         // 根据code处理客户端的请求
         return true;
       }
    
       onConnect(want: Want) {
         const robj: rpc.RemoteObject = new Stub("rpcTestAbility");
         return robj;
       }
     }
  4. 客户端处理服务端响应

    客户端在onConnect回调里接收到代理对象,调用sendMessageRequest方法发起请求,在期约(用于表示一个异步操作的最终完成或失败及其结果值)或者回调函数里接收结果。

     import { rpc } from '@kit.IPCKit';
     import { hilog } from '@kit.PerformanceAnalysisKit';
    
     // 使用期约
     let option = new rpc.MessageOption();
     let data = rpc.MessageSequence.create();
     let reply = rpc.MessageSequence.create();
     // 往data里写入参数
     let proxy: rpc.IRemoteObject | undefined;
     if (proxy != undefined) {
       proxy.sendMessageRequest(1, data, reply, option)
         .then((result: rpc.RequestResult) => {
           if (result.errCode != 0) {
             hilog.error(0x0000, 'testTag', 'sendMessageRequest failed, errCode: ' + result.errCode);
             return;
           }
           // 从result.reply里读取结果
         })
         .catch((e: Error) => {
           hilog.error(0x0000, 'testTag', 'sendMessageRequest got exception: ' + e);
         })
         .finally(() => {
           data.reclaim();
           reply.reclaim();
         })
     }
    
     // 使用回调函数
     function sendRequestCallback(err: Error, result: rpc.RequestResult) {
       try {
         if (result.errCode != 0) {
           hilog.error(0x0000, 'testTag', 'sendMessageRequest failed, errCode: ' + result.errCode);
           return;
         }
         // 从result.reply里读取结果
       } finally {
           result.data.reclaim();
           result.reply.reclaim();
       }
     }
     let options = new rpc.MessageOption();
     let datas = rpc.MessageSequence.create();
     let replys = rpc.MessageSequence.create();
     // 往data里写入参数
     if (proxy != undefined) {
       proxy.sendMessageRequest(1, datas, replys, options, sendRequestCallback);
     }
  5. 断开连接

    IPC通信结束后,FA模型使用featureAbility的接口断开连接,Stage模型在获取context后用提供的接口断开连接。

     // FA模型需要从@kit.AbilityKit导入featureAbility
     // import { featureAbility } from "@kit.AbilityKit";
     import { Want, common } from '@kit.AbilityKit';
     import { rpc } from '@kit.IPCKit';
     import { hilog } from '@kit.PerformanceAnalysisKit';
    
     function disconnectCallback() {
       hilog.info(0x0000, 'testTag', 'disconnect ability done');
     }
     // FA模型使用此方法断开连接
     // featureAbility.disconnectAbility(connectId, disconnectCallback);
    
     let proxy: rpc.IRemoteObject | undefined;
     let connectId: number;
    
     // 单个设备绑定Ability
     let want: Want = {
       // 包名和组件名写实际的值
       bundleName: "ohos.rpc.test.server",
       abilityName: "ohos.rpc.test.server.ServiceAbility",
     };
     let connect: common.ConnectOptions = {
       onConnect: (elementName, remote) => {
         proxy = remote;
       },
       onDisconnect: (elementName) => {
       },
       onFailed: () => {
         proxy;
       }
     };
     // FA模型使用此方法连接服务
     // connectId = featureAbility.connectAbility(want, connect);
    
     connectId = this.context.connectServiceExtensionAbility(want,connect);
    
     this.context.disconnectServiceExtensionAbility(connectId);

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