一、UDP客户端
1.1UDP协议相关API介绍
socket.h接口简介:这个socket.h中包含声明UDP协议相关接口函数。
1.2UDP客户端创建流程介绍
1.3实现UDP客户端
打开"D3_ iot udp client" 工程的udp client. demo.c文件，可在代码中查看实现UDP客户端的代码。
g_ _wifi EventHandler .0nHotspotStaJoin = OnHotspotStaJoinHandler;
g_ wifiEventHandler .0nHotspotStaleave = OnHotspotStaLeaveHandler;
g_ wifiEventHandler .OnHotspotStateChanged = OnHotspotStateChangedHandler ;
error = RegisterWifiEvent (&g_ WifiEventHandler);
if (error != WIFI_ SUCCESS)
printf(' "RegisterWifiEvent failed, error = %d. \r\n" , error);
return -1;
HotspotConfig config = {0};
strcpy( config.ssid, AP_ SSID);
strcpy( config . preSharedKey, AP_ PSK);
config. securityType = WIFI_ _SEC_ TYPE_ _PSK;
config. band = HOTSPOT BAND_ TYPE_ _2G;
config. channelNum = 7;
error = SetHotspotConfig(&config);
if (error != WIFI_ SUCCESS)
printf("SetHotspotConfig failed, error = %d.\r\n", error);
return -1;
}
error = EnableHotspot();
if (error != WIFI_ SUCCESS)
printf("EnableHotspot failed, error = %d.\r\n"， error);
return -1;
}
if (IsHotspotActive() == WIFI_ HOTSPOT_ NOT_ ACTIVE)
printf("Wifi station is not actived. \r\n");
return -1;
g_ apEnableSuccess = 0;
WaitAResult();
二、TCP服务端
2.1TCP协议相关API介绍
socket.h接口简介:这个socket.h中包含声明TCP协议相关接口函数。
2.2TCP服务端创建流程介绍
2.3实现TCP服务端
打开"D4 iot tcp server"工程的tcp_ server_ demo.c文件,， 可以查看实现
TCP服务的代码。
g_ _wifi EventHandler .0nHotspotStaJoin = OnHotspotStaJoinHandler;
g_ wifiEventHandler .0nHotspotStaLeave = OnHotspotStaleaveHandler;
g_ wifiEventHandler .0nHotspotStateChanged = OnHotspotStateChangedHandler;
error = RegisterWifiEvent (&g_ WifiEventHandler);
if (error != WIFI_ SUCCESS)
{printf( " RegisterWi fiEvent failed, error = %d. \r\n" , error);
return -1;}
HotspotConfig config = {0};
strcpy(config.ssid, AP_ SSID);
strcpy( config . preSharedKey, AP_ PSK);
config. securityType = WIFI_ SEC_ TYPE_ PSK;
config. band = HOTSPOT BAND_ TYPE_ _2G;
config . channelNum = 7;
error = SetHotspotConfig(&config);
if (error != WIFI_ SUCCESS)
{printf( "SetHotspotConfig failed, error = %d. \r\n", error);
return -1;}
error = EnableHotspot();
if (error != WIFI_ SUCCESS)
{printf("EnableHotspot failed, error = %d.\r\n", error);
return -1;}
if (IsHotspotActive() == WIFI_ HOTSPOT_ NOT_ _ACTIVE)
{printf("Wifi station is not actived. \r\n");
return -1;}
g_ apEnableSuccess = 0;
WaitAPResult();
三、TCP客户端
实现TCP客户端
static void TCPClientTask(void)
struct sockaddr_ in send_ addr;
socklen_ _t addr_ 1ength = sizeof(send_ addr);
char recvBuf[512];
Wi fiConnect( "Hold"，" 0987654321");
if ((sock_ fd = socket(AF_ INET, SOCK_ STREAM, 0)) == -1)
{perror(" create socket failed ! \r\n");
exit(1);}
send_ addr.sin_ family = AF_ INET;
send_ addr.sin_ port = htons(_ PROT_ );
send_ addr.sin_ addr.s_ addr = inet_ addr("192. 168 .0.175");
addr_ 1ength = sizeof(send_ addr);
connect(sock_ fd，(struct sockaddr *)&send_ addr, addr_ 1ength);
while (1){
bzero(recvBuf, sizeof(recvBuf));
if ((ret = send(sock_ fd, send_ data, strlen(send_ data), 0)) == -1)
{perror("send : ");}
if ((ret = recv(sock_ fd, recvBuf, sizeof(recvBuf), 0) == -1)
{printf("recv error \r\n");}
printf("recv :%s\r\n"， recvBuf);
}
close(sock_ fd);
}
四、UDP服务端
static void UDPServerTask( void)
struct sockaddr. _in server. sock;
struct sockaddr_ in client_ sock;
socklen_ t sin_ size;
WifiConnect( "Hold"，"0987654321");
if ((sock. _fd = socket(AF_ _INET, SOCK_ DGRAM， 0)) == -1)
{perror("socket is error\r\n");
exit(1);}
bzero(&server_ sock, sizeof(server_ sock));
server_ sock.sin_ family = AF_ INET;
server. sock.sin_ addr.s_ addr = htonl(INADDR _ANY);
server_ sock.sin_ port = htons(_ PROT. );
if (bind(sock_ fd，(struct sockaddr *)&server_ sock, sizeof(server. sock)) == -1)
{perror("bind is error\r\n");
exit(1);}
ssize_ t ret;
while (1)
{
sin_ size = sizeof (struct sockaddr. in);
bzero(recvbuf，sizeof(recvbuf));
if ((ret = recvfrom(sock_ _fd, recvbuf, sizeof(recvbuf)， 0，(struct sockaddr *)&client_ sock, &sin_ size)) == -1)
{
printf("recv error \r\n");
}
printf("recv :%s\r\n", recvbuf);
if ((ret = sendto(sock _fd，buf, strlen(buf)， 0，(struct sockaddr * )&client_ sock, sizeof(client_ sock))) == -1)
{perror("send : ");}
}
}
}
五、MQTT客户端
5.1MQTT介绍
MQTT (Message Queuing Tel emetry Transport, 消息队列遥测传输协议)，是一种基于发布/订阅(publis h/ subscribe)模式的‘轻量级通讯协议，该协议构建于TCP/ IP协议上，由IBM在1999年发布。
Paho是IBM在2011年建立的Eclipse开源项目,该项目包含以C. Java. Python, Javascript等语言编写的可用客户端。
5.2Paho MQTT文件目录介绍
●MQTTClient: 封装MQTTPacket生成的高级别C++客户端程序。
●MQTTClient-C: 封装MQTTPacket生成的高级别C客户端程序
samples目录提供F reeRTOS和1 inux两个例程,分别支持FreeRTOS和
Linux系统。
src目录提供MQTTClient的代码实现能力，以及用于移植到对应平台的
网络驱动
●MQTTPacket: 提供MQTT数据包的序列化与反序列化，以及部分辅助
函数。
5.3如何使用Paho MQTT协议
5.4实现MQTT客户端
打开"D5 iot_ mqtt"工程的iot mqtt.c文件,查看实现MQTT客户端的代码。
NetworkConnect (&network，"192. 168.0.175"，1883);
printf("MQTTClientInit ... \n")
MQTTClientInit(&client，&network， 2000， sendBuf, sizeof(sendBuf)， readBuf, sizeof(readBuf));
MQTTString clientId = MQTTString. initializer;
clientId.cstring = "bearpi";
MQTTPacket_ connectData data = MQTTPacket_ connectData_ initializer;
data. clientID = clientId;
data . willFlag = 0
data . MQT TVersion = 3
data . keepAliveInterval = 0
data . cleansession =1
printf ("MQTTConnect ... \n");
rc = MQTTConnect(&client, &data);
if(rc!=0){
printf("MQTTConnect: %d\n"， rc);
NetworkDisconnect ( &network);
MQTTDisconnect(&client);
osDelay(200);
goto begin;
}
printf("MQTTSubscribe ...\n");
rc = MQTTSubscribe(&client， "test", 2，messageArrived);
if(rc!=0){
printf("MQTTSubscribe: %d\n"， rc);
osDelay(200);
goto begin;
}
while (++count)
{
MQTTMessage message;
char payload[30];
message .q0S = 2;
message. retained = 0
message . payload = payload;
sprintf( payload, "message number %d"，count);
message . payloadlen = strlen(payload);
if (rc = MQTTPublish(&client, " pubtopic", &message)) != 0)
{
printf("Return code from MQTT publish is %d\n"， rc);
NetworkDi sconnect (&network);
MQTTDisconnect(&client);
goto begin;
}
osDelay(50);
}
