FunASR/funasr/runtime/websocket/websocketsrv.cpp

/**
 * Copyright FunASR (https://github.com/alibaba-damo-academy/FunASR). All Rights
 * Reserved. MIT License  (https://opensource.org/licenses/MIT)
 */
/* 2022-2023 by zhaomingwork */

// websocket server for asr engine
// take some ideas from https://github.com/k2-fsa/sherpa-onnx
// online-websocket-server-impl.cc, thanks. The websocket server has two threads
// pools, one for handle network data and one for asr decoder.
// now only support offline engine.

#include "websocketsrv.h"

#include <thread>
#include <utility>
#include <vector>

// feed buffer to asr engine for decoder
void WebSocketServer::do_decoder(const std::vector<char>& buffer,
                                 websocketpp::connection_hdl& hdl) {
  try {
    int num_samples = buffer.size();  // the size of the buf

    if (!buffer.empty()) {
      // fout.write(buffer.data(), buffer.size());
      // feed data to asr engine
      FUNASR_RESULT Result = FunASRRecogPCMBuffer(
          asr_hanlde, buffer.data(), buffer.size(), 16000, RASR_NONE, NULL);

      std::string asr_result =
          ((FUNASR_RECOG_RESULT*)Result)->msg;  // get decode result

      websocketpp::lib::error_code ec;
      nlohmann::json jsonresult;        // result json
      jsonresult["text"] = asr_result;  // put result in 'text'

      // send the json to client
      server_->send(hdl, jsonresult.dump(), websocketpp::frame::opcode::text,
                    ec);

      std::cout << "buffer.size=" << buffer.size()
                << ",result json=" << jsonresult.dump() << std::endl;
      if (!isonline) {
        //  close the client if it is not online asr
        server_->close(hdl, websocketpp::close::status::normal, "DONE", ec);
        // fout.close();
      }
    }

  } catch (std::exception const& e) {
    std::cerr << "Error: " << e.what() << std::endl;
  }
}

void WebSocketServer::on_open(websocketpp::connection_hdl hdl) {
  scoped_lock guard(m_lock);     // for threads safty
  check_and_clean_connection();  // remove closed connection
  sample_map.emplace(
      hdl, std::make_shared<std::vector<char>>());  // put a new data vector for
                                                    // new connection
  std::cout << "on_open, active connections: " << sample_map.size()
            << std::endl;
}

void WebSocketServer::on_close(websocketpp::connection_hdl hdl) {
  scoped_lock guard(m_lock);
  sample_map.erase(hdl);  // remove data vector when  connection is closed
  std::cout << "on_close, active connections: " << sample_map.size()
            << std::endl;
}

// remove closed connection
void WebSocketServer::check_and_clean_connection() {
  std::vector<websocketpp::connection_hdl> to_remove;  // remove list
  auto iter = sample_map.begin();
  while (iter != sample_map.end()) {  // loop to find closed connection
    websocketpp::connection_hdl hdl = iter->first;
    server::connection_ptr con = server_->get_con_from_hdl(hdl);
    if (con->get_state() != 1) {  // session::state::open ==1
      to_remove.push_back(hdl);
    }
    iter++;
  }
  for (auto hdl : to_remove) {
    sample_map.erase(hdl);
    std::cout << "remove one connection " << std::endl;
  }
}
void WebSocketServer::on_message(websocketpp::connection_hdl hdl,
                                 message_ptr msg) {
  unique_lock lock(m_lock);
  // find the sample data vector according to one connection
  std::shared_ptr<std::vector<char>> sample_data_p = nullptr;

  auto it = sample_map.find(hdl);
  if (it != sample_map.end()) {
    sample_data_p = it->second;
  }
  lock.unlock();
  if (sample_data_p == nullptr) {
    std::cout << "error when fetch sample data vector" << std::endl;
    return;
  }

  const std::string& payload = msg->get_payload();  // get msg type

  switch (msg->get_opcode()) {
    case websocketpp::frame::opcode::text:
      if (payload == "Done") {
        std::cout << "client done" << std::endl;

        if (isonline) {
          // do_close(ws);
        } else {
          // for offline, send all receive data to decoder engine
          asio::post(io_decoder_, std::bind(&WebSocketServer::do_decoder, this,
                                            std::move(*(sample_data_p.get())),
                                            std::move(hdl)));
        }
      }
      break;
    case websocketpp::frame::opcode::binary: {
      // recived binary data
      const auto* pcm_data = static_cast<const char*>(payload.data());
      int32_t num_samples = payload.size();

      if (isonline) {
        // if online TODO(zhaoming) still not done
        std::vector<char> s(pcm_data, pcm_data + num_samples);
        asio::post(io_decoder_, std::bind(&WebSocketServer::do_decoder, this,
                                          std::move(s), std::move(hdl)));
      } else {
        // for offline, we add receive data to end of the sample data vector
        sample_data_p->insert(sample_data_p->end(), pcm_data,
                              pcm_data + num_samples);
      }

      break;
    }
    default:
      break;
  }
}

// init asr model
void WebSocketServer::initAsr(std::map<std::string, std::string>& model_path,
                              int thread_num) {
  try {
    // init model with api

    asr_hanlde = FunASRInit(model_path, thread_num);
    std::cout << "model ready" << std::endl;

  } catch (const std::exception& e) {
    std::cout << e.what() << std::endl;
  }
}