Thank Kento a lot.
That's work for me!
Vào lúc 20:52:34 UTC+7 ngày Thứ Hai, 12 tháng 9, 2022,
[email protected] đã viết:
> Hi Thuy,
>
> Your code doesn't work because it tries to use nested WaitScopes. When a
> server-side method is called, the event loop is already running, so you
> have to use promise.then(lambda) instead of promise.wait(waitScope).
>
> So instead of this:
>
> auto& waitScope = ezClient2.getWaitScope();
> {
> auto request = client2.functionSampleRequest(); //Request to SERVER2
> request.setIn(222);
> auto promise = request.send();
>
> promise.wait(waitScope);
>
> }
>
> return kj::READY_NOW;
>
> Try:
>
> auto request = client2.functionSampleRequest(); //Request to SERVER2
> request.setIn(222);
> return request.send()
> .then([context](capnp::Response<Server2::SampleRequestResult>
> response) {
> // You can handle the response from server2 here if you want.
> // If there's nothing to do, you can replace `.then()` with
> `.ignoreResult()`.
> })
>
> -Kenton
>
> On Mon, Sep 12, 2022 at 2:40 AM Thuy Doan <[email protected]> wrote:
>
>> Hi all,
>>
>> I am a newbie to CapnProto. I'd like to have your help.
>>
>> I want to request a function of server2 in the callback of server1.
>> But I got an exception like below.
>> Please help me resolve it.
>> Many thanks!
>>
>> * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS
>> (code=1, address=0x3000000000020)
>> * frame #0: 0x000000010035859c
>> libcapnp-rpc-0.10.2.dylib`capnp::VatNetwork<capnp::rpc::twoparty::VatId,
>> capnp::rpc::twoparty::ProvisionId, capnp::rpc::twoparty::RecipientId,
>> capnp::rpc::twoparty::ThirdPartyCapId,
>> capnp::rpc::twoparty::JoinResult>::baseConnect(capnp::AnyStruct::Reader) + 20
>> frame #1: 0x0000000100361a2c
>> libcapnp-rpc-0.10.2.dylib`kj::_::TransformPromiseNode<kj::_::Void,
>> kj::Own<kj::AsyncIoStream>, capnp::EzRpcClient::Impl::Impl(kj::StringPtr,
>> unsigned int, capnp::ReaderOptions)::'lambda'(kj::Own<kj::AsyncIoStream>&&),
>> kj::_::PropagateException>::getImpl(kj::_::ExceptionOrValue&) + 512
>> frame #2: 0x00000001004d2220
>> libkj-async-0.10.2.dylib`kj::_::RunnableImpl<kj::_::TransformPromiseNodeBase::get(kj::_::ExceptionOrValue&)::$_31>::run()
>> + 32
>> frame #3: 0x000000010028aaa4
>> libkj-0.10.2.dylib`kj::_::runCatchingExceptions(kj::_::Runnable&) + 40
>> frame #4: 0x00000001004c7e48
>> libkj-async-0.10.2.dylib`kj::_::TransformPromiseNodeBase::get(kj::_::ExceptionOrValue&)
>> + 64
>> frame #5: 0x00000001004c8684
>> libkj-async-0.10.2.dylib`kj::_::ForkHubBase::fire() + 60
>> frame #6: 0x00000001004c654c
>> libkj-async-0.10.2.dylib`kj::_::waitImpl(kj::Own<kj::_::PromiseNode>&&,
>> kj::_::ExceptionOrValue&, kj::WaitScope&, kj::SourceLocation) + 608
>> frame #7: 0x0000000100005198
>> client`kj::Promise<capnp::Response<SampleServer1::CallbackRegisterResults>
>> >::wait(kj::WaitScope&, kj::SourceLocation) + 120
>> frame #8: 0x0000000100004b94 client`main + 344
>> frame #9: 0x000000010003d08c dyld`start + 520
>>
>> *Sample source code as below*
>>
>> *SampleServer1.capnp:*
>>
>> interface SampleServer1 {
>>
>> callbackRegister @0 (callback :Callback) -> (); //to register a
>> callback
>>
>> interface Callback {
>> calbackFunc @0 (in :Int32) -> ();
>> }
>> }
>>
>> *SampleServer1::Server Impl:*
>>
>> class SampleServer1Impl : public SampleServer1::Server
>> {
>> ::kj::Promise<void> callbackRegister(CallbackRegisterContext context){
>> auto cb = context.getParams().getCallback());
>>
>> auto request = cb.calbackFuncRequest(); //Call callback function
>> request.setIn(111);
>> auto promise = request.send();
>>
>> return kj::READY_NOW;
>> }
>> }
>>
>> *SampleServer1::Callback::Server Impl:*
>>
>> class CallbackImpl : public SampleServer1::Callback::Server
>> {
>> ::kj::Promise<void> calbackFunc(CalbackFuncContext context){
>>
>> capnp::EzRpcClient ezClient2("unix:/tmp/capnp-server-2");
>> Server2::Client client2 = ezClient2.getMain<SampleServer2>();
>>
>> auto& waitScope = ezClient2.getWaitScope();
>> {
>> auto request = client2.functionSampleRequest(); //Request to SERVER2
>> request.setIn(222);
>> auto promise = request.send();
>>
>> promise.wait(waitScope);
>>
>> }
>>
>> return kj::READY_NOW;
>> }
>> }
>>
>> *SampleServer2.capnp:*
>>
>> interface SampleServer2 {
>>
>> functionSample @0 (in :Int32) -> ();
>> }
>>
>> *SampleServer2::Server impl*
>>
>> class SampleServer2 Impl : public SampleServer2::Server
>> {
>> ::kj::Promise<void> functionSample(FunctionSampleContext context){
>> //Do something
>> return kj::READY_NOW;
>> }
>> }
>>
>> *Client implement*
>>
>> capnp::EzRpcClient ezClient("unix:/tmp/capnp-server-1");
>> Subscriber::Client client = ezClient.getMain<SampleServer1>();
>> auto& waitScope = ezClient.getWaitScope();
>>
>> ::SampleServer1::Callback::Client callback =
>> ::SampleServer1::Callback::Client(kj::heap<CallbackImpl>());
>>
>> auto request = client.callbackRegisterRequest(); //Register a
>> callback to Server1
>> request.setCallback(callback);
>> auto promise = request.send();
>>
>>
>> --
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>>
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>>
>
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