freeswitch mrcp 源码分析--数据接收（下）

最新推荐文章于 2023-03-17 21:00:00 发布

罗自荣

最新推荐文章于 2023-03-17 21:00:00 发布

阅读量3.5k

点赞数 1

CC 4.0 BY-SA版权

分类专栏： freeswitch

本文链接：https://blog.youkuaiyun.com/luozirong/article/details/78876787

本文深入分析了Freeswitch中MRCP数据接收的流程，从apr_queue_pop取出数据，经过apt_task_msg_process、mrcp_client_msg_process，直至调用recog_message_handler和mrcp_application_message_dispatch。重点讲解了消息处理路径及在recog_on_message_receive中执行的三个关键步骤：设置识别结果头部信息、设置识别结果内容和更新通道状态。

这里写图片描述
在前两篇我们介绍了mrcp接收后的处理，最后会调用apr_queue_push扔到消息队列里面。
对应的，在apt_consumer_task.apt_consumer_task_run（）中会循环调用pr_queue.apr_queue_pop（）从队列里面取出数据：

apt_consumer_task.apt_consumer_task_run –>
apr_queue.apr_queue_pop –>
apt_task.apt_task_msg_process –>
mrcp_client.mrcp_client_msg_process –>
mrcp_client_session.mrcp_client_on_message_receive–>
mrcp_client_session.mrcp_app_control_message_raise–>
mod_unimrcp.recog_message_handler –> mrcp_application.mrcp_application_message_dispatch–>
mod_unimrcp.recog_on_message_receive–>
mod_unimrcp.recog_channel_set_result_headers–>
mod_unimrcp.recog_channel_set_results–>
mod_unimrcp.speech_channel_set_state

在apt_consumer_task_run中是一个while循环，调用apr_queue_pop不断去读取队列数据。然后调用apt_task_msg_process处理取出来的数据。

APT_DECLARE(apt_bool_t) apt_task_msg_process(apt_task_t *task, apt_task_msg_t *msg)
{
    apt_bool_t status = FALSE;
    apt_log(APT_LOG_MARK,APT_PRIO_DEBUG,"Process Message [%s] ["APT_PTR_FMT";%d;%d]",
        task->name, msg, msg->type, msg->sub_type);
    if(msg->type == TASK_MSG_CORE) {
        status = apt_core_task_msg_process(task,msg);
    }
    else {
        if(task->vtable.process_msg) {
            status = task->vtable.process_msg(task,msg);
        }
    }

    apt_task_msg_release(msg);
    return status;
}

这里主要调用task->vtable.process_msg来处理。在mrcp_client_create函数中，process_msg 被赋值为mrcp_client_msg_process：

vtable = apt_task_vtable_get(task);
    if(vtable) {
        vtable->process_msg = mrcp_client_msg_process;
        vtable->on_start_complete = mrcp_client_on_start_complete;
        vtable->on_terminate_complete = mrcp_client_on_terminate_complete;
    }

所以实际上调用的是mrcp_client_msg_process（）。消息的type为：MRCP_CLIENT_CONNECTION_TASK_MSG，subtype为：CONNECTION_AGENT_TASK_MSG_RECEIVE_MESSAGE，所以会调用mrcp_client_on_message_receive，进而调用mrcp_app_control_message_raise（）。

static apt_bool_t mrcp_app_control_message_raise(mrcp_client_session_t *session, mrcp_channel_t *channel, mrcp_message_t *mrcp_message)
{
    if(mrcp_message->start_line.message_type == MRCP_MESSAGE_TYPE_RESPONSE) {
        mrcp_app_message_t *response;
        mrcp_message_t *mrcp_request;
        if(!session->active_request || !session->active_request->control_message) {
            return FALSE;
        }
        response = mrcp_client_app_response_create(session->active_request,0,session->base.pool);
        mrcp_request = session->active_request->control_message;
        mrcp_message->start_line.method_id = mrcp_request->start_line.method_id;
        mrcp_message->start_line.method_name = mrcp_request