搭建CG28181 服务端,也即 SIP Server,这正是我们要实现的。实现CG28181服务端可以借助于现有的开源库 PJSIP,具体的实现步骤如下:
1、启动GB28181服务端,接收客户端消息请求
bool Init(std::string concat, int logLevel)
{
this->concat = concat;
pj_log_set_level(logLevel);
auto status = pj_init();
status = pjlib_util_init();
pj_caching_pool_init(&cachingPool, &pj_pool_factory_default_policy, 0);
status = pjsip_endpt_create(&cachingPool.factory, nullptr, &endPoint);
status = pjsip_tsx_layer_init_module(endPoint);
status = pjsip_ua_init_module(endPoint, nullptr);
pool = pj_pool_create(&cachingPool.factory, "proxyapp", 4000, 4000, nullptr);
auto pjStr =StrToPjstr(GetAddr());
pj_sockaddr_in pjAddr;
pjAddr.sin_family = pj_AF_INET();
pj_inet_aton(&pjStr, &pjAddr.sin_addr);
auto port = GetPort();
pjAddr.sin_port = pj_htons(static_cast<pj_uint16_t>(GetPort()));
status = pjsip_udp_transport_start(endPoint, &pjAddr, nullptr, 1, nullptr);
if (status != PJ_SUCCESS) return status;
auto realm = StrToPjstr(GetLocalDomain());
return pjsip_auth_srv_init(pool, &authentication, &realm, lookup, 0) == PJ_SUCCESS ? true : false;
}
以上是PJSip初始化的代码,需要将服务将要监听的端口传给PJSIP,这样服务就在监听的端口接收SIP 消息了。
2、应答注册消息
摄像机端发送来Register消息后,如果服务端不应答,摄像机端会一直发送直到收到服务端应答为止。如果服务器端重新运行,需要手动再次开启设备。
服务端应答注册消息代码如下:
bool OnReceive(pjsip_rx_data* rdata) override
{
if(rdata->msg_info.cseq->method.id == PJSIP_REGISTER_METHOD)
{
auto expires = static_cast<pjsip_expires_hdr*>(pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_EXPIRES, nullptr));
auto authHdr = static_cast<pjsip_authorization_hdr*>(pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_AUTHORIZATION, nullptr));
if(expires && expires->ivalue > 0 )
{
if(authHdr)
{
cout <<"receive register info"<<endl;
response(rdata, PJSIP_SC_OK, DateHead);
QureryDeviceInfo(rdata);
}
else
{
response(rdata, PJSIP_SC_UNAUTHORIZED, AuthenHead);
}
return true;
}
}
return false;
}
OnReceive 是服务端接收注册消息以后的响应方法,也就是说要将OnReceive作为入参传给PJSIP,完成此项功能在初始化<br>PJSIP Moudle时。至于PJSIP moudle,细节的话,可以查看PJSIP文档,代码如下:
bool Init(std::string concat, int loglevel)
{
bool ret = false;
if(!mainModule)
{
ret = context.Init(concat,loglevel);
if(!ret) return ret;
static struct pjsip_module moudle =
{
nullptr,
nullptr,
{ "MainModule", 10 },
-1,
PJSIP_MOD_PRIORITY_APPLICATION,
nullptr,
nullptr,
nullptr,
nullptr,
nullptr,
&CGSipMedia::OnReceive,
nullptr,
nullptr,
nullptr,
};
mainModule = &moudle;
pjsip_inv_callback callback;
pj_bzero(&callback, sizeof(callback));
callback.on_state_changed = &onStateChanged;
callback.on_new_session = &onNewSession;
callback.on_tsx_state_changed = &onTsxStateChanged;
callback.on_rx_offer = &onRxOffer;
callback.on_rx_reinvite = &onRxReinvite;
callback.on_create_offer = &onCreateOffer;
callback.on_send_ack = &onSendAck;
ret = context.RegisterCallback(&callback);
if(!ret ) return ret;
context.InitModule();
ret = context.RegisterModule(mainModule);
if(!ret ) return ret;
CGSipModule::GetInstance().Init();
ret = context.CreateWorkThread(&proc,workthread,nullptr,"proxy");
}
return ret;
}
OnReceive方法内Resonse方法实现了发送响应数据到客户端(设备):
接到PJSIP发送一些字符串给客户端:
void Response(pjsip_rc_data* rdata, int st_code, int headType)
{
std::lock_guard<mutex> lk(lock);
pjsip_tx_data* tdata;
pjsip_endpt_create_response(endPoint, rdata, st_code, nullptr, &tdata);
auto date = DateTimeFormatter::format(LocalDateTime(), "Y-%m-%dT%H:%M:%s");
pj_str_t c;
pj_str_t key;
pjsip_hdr * hdr;
switch(headType)
{
case DateHead:
key = pj_str("Date");
hdr = reinterpret_cast<pjsip_hdr*>(pjsip_date_hdr_create(poll, &key, pj_cstr(&c, date.c_str())));
pjsip_msg_add_hdr(tdata->msg, hdr);
break;
case AuthenHead:
pjsip_auth_srv_challenge(&authentication, nullptr, nullptr, nullptr, PJ_FALSE, tdata);
break;
default:
break;
}
pjsip_response_addr addr;
pjsip_get_response_addr(pool, rdata, &addr);
pjsip_endpt_send_response(endPoint, &addr, tdata, nullptr, nullptr);
}
SIP服务端响应注册命令后,发送Invite请求,请求catalog信息,也就是设备基本信息,具体的方法上面已
给出,具体的内容是:
bool OnReceive(pjsip_rx_data* rdata) override
{
if (rdata->msg_info.cseq->method.id == PJSIP_OTHER_METHOD)
{
CGXmlParser xmlParser(context.GetMessageBody(rdata));
CGDynamicStruct dynamicStruct;
dynamicStruct.Set(xmlParser.GetXml());
auto cmd = xmlParser.GetXml()->firstChild()->nodeName();
auto cmdType = dynamicStruct.Get<std::string>("CmdType");
if (cmdType != "Catalog") return false;
auto DeviceID = dynamicStruct.Get<std::string>("DeviceID");
Vector deviceList = dynamicStruct.Get<Vector>("DeviceList");
for (auto& x : deviceList)
{
CGCatalogInfo devinfo;
try
{
devinfo.PlatformAddr = rdata->pkt_info.src_name;
devinfo.PlatformPort = rdata->pkt_info.src_port;
devinfo.Address = x["Address"].convert<string>();
devinfo.Name = WstringToString(x["Name"].convert<wstring>());
devinfo.Manufacturer = x["Manufacturer"].convert<string>();
devinfo.Model = x["Model"].convert<string>();
devinfo.Owner = x["Owner"].convert<string>();
devinfo.Civilcode = x["CivilCode"].convert<string>();
devinfo.Registerway = x["RegisterWay"].convert<int>();
devinfo.Secrecy = x["Secrecy"].convert<int>();
//devinfo.IPAddress = x["IPAddress"].convert<string>();
devinfo.DeviceID = x["DeviceID"].convert<string>();
devinfo.Status= x["Status"].convert<string>();
}
catch (...)
{
//continue;
}
if(callback)
{
callback(user, &devinfo);
}
//SipControlModule::GetInstance().CatalogCallBack(devinfo);
}
response(rdata, PJSIP_SC_OK,NoHead);
return true;
}
SIP服务端获取设备端的信息后就可以发送请求视频信息了,请求视频最为关键的是SDP,下面看下SDP信息如何填写:
static string createSDP(MediaContext& mediaContext)
{
char str[500] = { 0 };
pj_ansi_snprintf(str, 500,
"v=0\n"
"o=%s 0 0 IN IP4 %s\n"
"s=Play\n"
"c=IN IP4 %s\n"
"t=0 0\n"
"m=video %d RTP/AVP 96 98 97\n"
"a=recvonly\n"
"a=rtpmap:96 PS/90000\n"
"a=rtpmap:98 H264/90000\n"
"a=rtpmap:97 MPEG4/90000\n"
"y=0100000001\n",
mediaContext.GetDeviceId().c_str(),
mediaContext.GetRecvAddress().c_str(),
mediaContext.GetRecvAddress().c_str(),
mediaContext.GetRecvPort()
);
return str;
}
发送请求视频命令到设备端也是通过PJSIP API实现,实现代码如下:
bool Invite(pjsip_dialog *dlg, MediaContext mediaContext, string sdp)
{
pjsip_inv_session *inv;
if (PJ_SUCCESS != pjsip_inv_create_uac(dlg, nullptr, 0, &inv)) return false;
pjsip_tx_data *tdata;
if (PJ_SUCCESS != pjsip_inv_invite(inv, &tdata)) return false;
pjsip_media_type type;
type.type = pj_str("application");
type.subtype = pj_str("sdp");
auto text = pj_str(const_cast<char *>(sdp.c_str()));
try
{
tdata->msg->body = pjsip_msg_body_create(pool, &type.type, &type.subtype, &text);
auto hName = pj_str("Subject");
auto subjectUrl = mediaContext.GetDeviceId() + ":" + SiralNum + "," + GetInstance().GetCode() + ":" + SiralNum;
auto hValue = pj_str(const_cast<char*>(subjectUrl.c_str()));
auto hdr = pjsip_generic_string_hdr_create(pool, &hName, &hValue);
pjsip_msg_add_hdr(tdata->msg, reinterpret_cast<pjsip_hdr*>(hdr));
pjsip_inv_send_msg(inv, tdata);
}
catch (...)
{
}
return true;
}
设备端收到Invite请求后,会将视频数据以rtp的方式推送到指定的端口,端口在invite消息指定。这样在指定的地址(ip + port)就可以拿到数据了。
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