harmony 鸿蒙IPC与RPC通信开发指导
IPC与RPC通信开发指导
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。
接口说明
表1 Native侧IPC接口
类/接口 | 方法 | 功能说明 |
---|---|---|
IRemoteBroker | sptr<IRemoteObject> AsObject() | 返回通信对象。Stub端返回RemoteObject对象本身,Proxy端返回代理对象。 |
IRemoteStub | virtual int OnRemoteRequest(uint32_t code, MessageParcel &data, MessageParcel &reply, MessageOption &option) | 请求处理方法,派生类需要重写该方法用来处理Proxy的请求并返回结果。 |
IRemoteProxy | Remote()->SendRequest(code, data, reply, option) | 消息发送方法,业务的Proxy类需要从IRemoteProxy类派生,该方法用来向对端发送消息。 |
开发步骤
Native侧开发步骤
- 添加依赖
SDK依赖:
#ipc场景
external_deps = [
"ipc:ipc_single",
]
#rpc场景
external_deps = [
"ipc:ipc_core",
]
此外, IPC/RPC依赖的refbase实现在公共基础库下,请增加对utils的依赖:
external_deps = [
"c_utils:utils",
]
- 定义IPC接口ITestAbility
SA接口继承IPC基类接口IRemoteBroker,接口里定义描述符、业务函数和消息码,其中业务函数在Proxy端和Stub端都需要实现。
#include "iremote_broker.h"
//定义消息码
const int TRANS_ID_PING_ABILITY = 5;
const std::string DESCRIPTOR = "test.ITestAbility";
class ITestAbility : public IRemoteBroker {
public:
// DECLARE_INTERFACE_DESCRIPTOR是必需的,入参需使用std::u16string;
DECLARE_INTERFACE_DESCRIPTOR(to_utf16(DESCRIPTOR));
virtual int TestPingAbility(const std::u16string &dummy) = 0; // 定义业务函数
};
- 定义和实现服务端TestAbilityStub
该类是和IPC框架相关的实现,需要继承 IRemoteStub<ITestAbility>。Stub端作为接收请求的一端,需重写OnRemoteRequest方法用于接收客户端调用。
#include "iability_test.h"
#include "iremote_stub.h"
class TestAbilityStub : public IRemoteStub<ITestAbility> {
public:
virtual int OnRemoteRequest(uint32_t code, MessageParcel &data, MessageParcel &reply, MessageOption &option) override;
int TestPingAbility(const std::u16string &dummy) override;
};
int TestAbilityStub::OnRemoteRequest(uint32_t code,
MessageParcel &data, MessageParcel &reply, MessageOption &option)
{
switch (code) {
case TRANS_ID_PING_ABILITY: {
std::u16string dummy = data.ReadString16();
int result = TestPingAbility(dummy);
reply.WriteInt32(result);
return 0;
}
default:
return IPCObjectStub::OnRemoteRequest(code, data, reply, option);
}
}
- 定义服务端业务函数具体实现类TestAbility
#include "iability_server_test.h"
class TestAbility : public TestAbilityStub {
public:
int TestPingAbility(const std::u16string &dummy);
}
int TestAbility::TestPingAbility(const std::u16string &dummy) {
return 0;
}
- 定义和实现客户端 TestAbilityProxy
该类是Proxy端实现,继承IRemoteProxy<ITestAbility>,调用SendRequest接口向Stub端发送请求,对外暴露服务端提供的能力。
#include "iability_test.h"
#include "iremote_proxy.h"
#include "iremote_object.h"
class TestAbilityProxy : public IRemoteProxy<ITestAbility> {
public:
explicit TestAbilityProxy(const sptr<IRemoteObject> &impl);
int TestPingAbility(const std::u16string &dummy) override;
private:
static inline BrokerDelegator<TestAbilityProxy> delegator_; // 方便后续使用iface_cast宏
}
TestAbilityProxy::TestAbilityProxy(const sptr<IRemoteObject> &impl)
: IRemoteProxy<ITestAbility>(impl)
{
}
int TestAbilityProxy::TestPingAbility(const std::u16string &dummy){
MessageOption option;
MessageParcel dataParcel, replyParcel;
dataParcel.WriteString16(dummy);
int error = Remote()->SendRequest(TRANS_ID_PING_ABILITY, dataParcel, replyParcel, option);
int result = (error == ERR_NONE) ? replyParcel.ReadInt32() : -1;
return result;
}
- SA注册与启动
SA需要将自己的TestAbilityStub实例通过AddSystemAbility接口注册到SystemAbilityManager,设备内与分布式的注册参数不同。
// 注册到本设备内
auto samgr = SystemAbilityManagerClient::GetInstance().GetSystemAbilityManager();
samgr->AddSystemAbility(saId, new TestAbility());
// 在组网场景下,会被同步到其他设备上
auto samgr = SystemAbilityManagerClient::GetInstance().GetSystemAbilityManager();
ISystemAbilityManager::SAExtraProp saExtra;
saExtra.isDistributed = true; // 设置为分布式SA
int result = samgr->AddSystemAbility(saId, new TestAbility(), saExtra);
- SA获取与调用
通过SystemAbilityManager的GetSystemAbility方法可获取到对应SA的代理IRemoteObject,然后构造TestAbilityProxy即可。
// 获取本设备内注册的SA的proxy
sptr<ISystemAbilityManager> samgr = SystemAbilityManagerClient::GetInstance().GetSystemAbilityManager();
sptr<IRemoteObject> remoteObject = samgr->GetSystemAbility(saId);
sptr<ITestAbility> testAbility = iface_cast<ITestAbility>(remoteObject); // 使用iface_cast宏转换成具体类型
// 获取其他设备注册的SA的proxy
sptr<ISystemAbilityManager> samgr = SystemAbilityManagerClient::GetInstance().GetSystemAbilityManager();
// networkId是组网场景下对应设备的标识符,可以通过GetLocalNodeDeviceInfo获取
sptr<IRemoteObject> remoteObject = samgr->GetSystemAbility(saId, networkId);
sptr<TestAbilityProxy> proxy(new TestAbilityProxy(remoteObject)); // 直接构造具体Proxy
JS侧开发步骤
- 添加依赖
import rpc from '@ohos.rpc';
// 仅FA模型需要导入@ohos.ability.featureAbility
// import featureAbility from '@ohos.ability.featureAbility';
Stage模型需要获取context
import UIAbility from '@ohos.app.ability.UIAbility';
import Want from '@ohos.app.ability.Want';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';
import window from '@ohos.window';
export default class MainAbility extends UIAbility {
onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
console.log("[Demo] MainAbility onCreate");
let context = this.context;
}
onDestroy() {
console.log("[Demo] MainAbility onDestroy");
}
onWindowStageCreate(windowStage: window.WindowStage) {
// Main window is created, set main page for this ability
console.log("[Demo] MainAbility onWindowStageCreate");
}
onWindowStageDestroy() {
// Main window is destroyed, release UI related resources
console.log("[Demo] MainAbility onWindowStageDestroy");
}
onForeground() {
// Ability has brought to foreground
console.log("[Demo] MainAbility onForeground");
}
onBackground() {
// Ability has back to background
console.log("[Demo] MainAbility onBackground");
}
}
- 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deviceManager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。
// 仅FA模型需要导入@ohos.ability.featureAbility
// import featureAbility from "@ohos.ability.featureAbility";
import rpc from '@ohos.rpc';
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import deviceManager from '@ohos.distributedHardware.deviceManager';
import { BusinessError } from '@ohos.base';
let dmInstance: deviceManager.DeviceManager|undefined;
let proxy: rpc.IRemoteObject|undefined = 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);
// 跨设备绑定
let deviceManagerCallback = (err: BusinessError, data: deviceManager.DeviceManager) => {
if (err) {
console.error("createDeviceManager errCode:" + err.code + ",errMessage:" + err.message);
return;
}
console.info("createDeviceManager success");
dmInstance = data;
}
try{
deviceManager.createDeviceManager("ohos.rpc.test", deviceManagerCallback);
} catch(error) {
let err: BusinessError = error as BusinessError;
console.error("createDeviceManager errCode:" + err.code + ",errMessage:" + err.message);
}
// 使用deviceManager获取目标设备NetworkId
if (dmInstance != undefined) {
let deviceList: Array<deviceManager.DeviceInfo> = dmInstance.getTrustedDeviceListSync();
let networkId: string = 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deviceManager的回调函数
connectId = this.context.connectServiceExtensionAbility(want,connect);
}
- 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 '@ohos.rpc';
import Want from '@ohos.app.ability.Want';
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;
}
}
- 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sendRequest方法发起请求,在期约(JavaScript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 '@ohos.rpc';
// 使用期约
let option = new rpc.MessageOption();
let data = rpc.MessageParcel.create();
let reply = rpc.MessageParcel.create();
// 往data里写入参数
let proxy: rpc.IRemoteObject|undefined = undefined;
proxy.sendRequest(1, data, reply, option)
.then((result: rpc.SendRequestResult) => {
if (result.errCode != 0) {
console.error("send request failed, errCode: " + result.errCode);
return;
}
// 从result.reply里读取结果
})
.catch((e: Error) => {
console.error("send request got exception: " + e);
})
.finally(() => {
data.reclaim();
reply.reclaim();
})
// 使用回调函数
function sendRequestCallback(result: rpc.SendRequestResult) {
try {
if (result.errCode != 0) {
console.error("send request 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.MessageParcel.create();
let replys = rpc.MessageParcel.create();
// 往data里写入参数
proxy.sendRequest(1, datas, replys, options, sendRequestCallback);
- 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。
import rpc from '@ohos.rpc';
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
// 仅FA模型需要导入@ohos.ability.featureAbility
// import featureAbility from "@ohos.ability.featureAbility";
function disconnectCallback() {
console.info("disconnect ability done");
}
// FA模型使用此方法断开连接
// featureAbility.disconnectAbility(connectId, disconnectCallback);
let proxy: rpc.IRemoteObject|undefined = 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);
相关实例
针对IPC与RPC通信开发,有以下相关实例可供参考:
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