README.md

C++ Speechly Api

The generated stubs for C++ can be copied from here to your project, making the protoc step unnecessary.

Check out an example application here.

IdentityAPI

Logging in with IdentityAPI is a single RPC call with appId and deviceId.

grpc::SslCredentialsOptions ssl_opts;
ssl_opts.pem_root_certs = "add certificates here";
auto channel_creds = grpc::SslCredentials(ssl_opts);
std::shared_ptr<Channel> identityChannel = grpc::CreateChannel("api.speechly.com", channel_creds);
std::unique_ptr<Identity::Stub> identityStub_ = Identity::NewStub(identityChannel);

LoginRequest request;
request.set_app_id(appId);
request.set_device_id(deviceId);
LoginResponse response;
ClientContext loginContext;

Status status = identityStub_->Login(&loginContext, request, &response);
std::string token = response.token();

SLU

Streaming SLU is a bidirectional RPC call to the API, which means that it is not no simple as the login example above. Use the token from the Identity response to create the SLU channel.

class MyCustomAuthenticator : public grpc::MetadataCredentialsPlugin {
 public:
  MyCustomAuthenticator(const grpc::string& ticket) : ticket_(ticket) {}

  grpc::Status GetMetadata(grpc::string_ref service_url, grpc::string_ref method_name, const grpc::AuthContext& channel_auth_context, std::multimap<grpc::string, grpc::string>* metadata) override {
    metadata->insert(std::make_pair("authorization", ticket_));
    return grpc::Status::OK;
  }

 private:
  grpc::string ticket_;
};

std::shared_ptr<grpc::CallCredentials> call_creds = grpc::MetadataCredentialsFromPlugin(std::unique_ptr<grpc::MetadataCredentialsPlugin>(new MyCustomAuthenticator("Bearer " + token)));

std::shared_ptr<Channel> sluChannel = grpc::CreateChannel("api.speechly.com", grpc::CompositeChannelCredentials(channel_creds, call_creds));

std::unique_ptr<SLU::Stub> sluStub_ = slu::v1::SLU::NewStub(sluChannel);

std::shared_ptr<ClientReaderWriter<SLURequest, SLUResponse> > stream(sluStub_->Stream(&context));

Start context

Before starting context need to send SLUConfig with Encoding and SampleRateHertz.

SLUConfig config;
config.set_encoding(SLUConfig_Encoding::SLUConfig_Encoding_LINEAR16);
config.set_sample_rate_hertz(16000);

SLURequest configRequest;
configRequest.mutable_config()->CopyFrom(config);

stream->Write(configRequest);

SLUEvent event;
event.set_event(slu::v1::SLUEvent_Event_START);
SLURequest startRequest;
startRequest.mutable_event()->CopyFrom(event);

stream->Write(startRequest);

Send audio

Audio should be sent in 16-bit / 16kHz format. In the example audio is an array of bytes and number is a number of chunks in the array.

SLURequest sluRequest;
sluRequest.set_audio(audio, number);
stream->Write(sluRequest);

Stop context

SLUEvent event;
event.set_event(slu::v1::SLUEvent_Event_STOP);
SLURequest stopRequest;
stopRequest.mutable_event()->CopyFrom(event);

stream->Write(stopRequest);