问题：客户端业务逻辑如何实现？与服务设施交互细节如何设计？

客户端业务逻辑实现

  • 用户输出解决

    • 字符串空格解决，宰割获取命令与参数

  • 服务信息处理

    • 字符串预处理，宰割获取服务命令
    • 存储服务命令与设施地址之间的映射（命令字符串 地址字符串）

客户端业务逻辑实现 - 用户输出解决

typedef struct {    const char *cmd;    char *(*handler)(const char *);}Handler;
static Handler g_handler[] = {    {"query", Query_Handler},    {"touch", Touch_Handler}};
if (*line) {    char **arg = Malloc2d(char, 2, BUF_SIZE);    int i = 0;    int r = DivideBy(line, ' ', arg, 2, BUF_SIZE);    if (i=0; i<DIM(g_handler); ++i) {        if (strcmp(g_handler[i].cmd, arg[0]) == 0) {            g_handler[i].handler(arg[1]);            break;        }    }    Free2d(arg);}

服务端逻辑实现

  • 查问音讯解决

    • 接管播送，并回复 UDP 音讯

  • 服务命令解决

    • 接管 TCP 连贯，通过 申请 - 响应 的模式进行服务

UDP 响应模式设计

static void Query_Handler(UdpPoint *udp, Message *msg, const char *remote, int port){    Message *resp = Message_New(TYPE_RESPONSE, 0, 0, 0, NULL, DESC_SIZE + ADDR_SIZE + USAGE_SIZE);    if (resp) {        char ip[16] = {0};        get_localip("ens33", ip);        strncpy(resp->payload, Service_GetDesc(), DESC_SIZE);        strncpy(resp->payload + DESC_SIZE, ip, ADDR_SIZE);        strncpy(resp->payload + DESC_SIZE + ADDR_SIZE, Service_GetUsage(), USAGE_SIZE);        UdpPoint_SendMsg(udp, resp, remote, port);    }    free(resp);}

服务模块设计

#ifndef LOCAL_SERVICE_H#define LOCAL_SERVICE_Htypedef struct {    float illumination;    float humidity;    float temperature;    int light;}SvrData;void Service_Init(void);const char *Service_GetDesc(void);const char *Service_GetUsage(void);SvrData Service_GetData(void);int Service_SetLight(int on);#endif // LOCAL_SERVICE_H

TCP 响应模块设计

Message *msg = TcpClient_RecvMsg(client);if (msg && (msg->type == TYPE_TOUCH)) {    static char buf[128] = {0};    SvrData ed = Service_GetData();        free(msg);  // provided by service module    msg = Message_New(TYPE_RESPONSE, 0, 0, 0, buf, strlen(buf) + 1);    // format data according to message payload string}else {    const char *message = "Invalid touch request";    free(msg);        msg = Message_New(TYPE_RESONSE, 0, 0, 0, message, strlen(message) + 1);}TcpClient_SendMsg(client, msg);free(msg);

客户端响应接管

msg = TcpClient_RecvMsg(client);if (msg && (msg->type == TYPE_RESPONSE)) {    printf("%s\n", msg->payload);} else {    printf("Invalid status from service ...\n");}free(msg);

编程试验： 客户端服务端交互实现

课后思考

服务模块如何获取真是环境信息