c - 如何在套接字中传递和接收命令行参数?
问题描述
我正在使用 C 处理套接字,并且需要将命令行参数从客户端传递到服务器。然后,服务器需要切换 sting 的大小写并将其发送回客户端。我坚持将命令行参数传递给服务器,然后在切换案例后将其发送回来。这是我到目前为止所拥有的:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#define PORT 10291
#define MAXLINE 9999
// Client side code
int main(int argc, char *argv[])
{
int sockfd;
char buffer[MAXLINE];
char clientMsg;
struct sockaddr_in servaddr;
// Creating socket file descriptor
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
{
perror("socket creation failed");
exit(EXIT_FAILURE);
}
memset(&servaddr, 0, sizeof(servaddr));
// Filling server information
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(PORT);
servaddr.sin_addr.s_addr = INADDR_ANY;
//Connect to the Server
connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr));
printf("Connected to the Server. \n");
int n, len;
// Getting Input From Client
/*
printf("Please Enter Your Message: ");
scanf("%s", &clientMsg);
*/
if (argc == 2)
{
for (int i = 0; argc; i++)
{
// send(sockfd, &argv[i], 10000, 0);
sendto(sockfd, (const char *) &clientMsg, strlen(&clientMsg),
MSG_CONFIRM, (const struct sockaddr *) &servaddr,
sizeof(servaddr));
}
printf("Message sent to server. \n");
}
else
{
printf("Error: please enter the correct number of arguments. \n");
close(sockfd);
printf("Disconnected from the server. \n");
exit(1);
}
/*
// Sending message to server
sendto(sockfd, (const char *) &clientMsg, strlen(&clientMsg),
MSG_CONFIRM, (const struct sockaddr *) &servaddr,
sizeof(servaddr));
printf("Message sent to server. \n");
*/
// Receive message from server
n = recvfrom(sockfd, (char*) buffer, MAXLINE,
MSG_WAITALL, (struct sockaddr *) &servaddr, &len);
buffer[n] = '\0';
printf("Message Received From Server: %s\n", buffer);
//Disconnet from the Server
close(sockfd);
printf("Disconneted from the Server. \n");
return 0;
}
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#define PORT 10291
#define MAXLINE 9999
// Server Side code
int main(int argc, char *argv[])
{
int sockfd;
char buffer[MAXLINE];
struct sockaddr_in servaddr, cliaddr;
// Creating socket file descriptor
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
{
perror("socket creation failed");
exit(EXIT_FAILURE);
}
memset(&servaddr, 0, sizeof(servaddr));
memset(&cliaddr, 0, sizeof(cliaddr));
// Filling server information
servaddr.sin_family = AF_INET; // IPv4
servaddr.sin_addr.s_addr = INADDR_ANY;
servaddr.sin_port = htons(PORT);
// Bind the socket with the server address
if (bind(sockfd, (const struct sockaddr *) &servaddr, sizeof(servaddr)) < 0)
{
perror("bind failed");
exit(EXIT_FAILURE);
}
int len, n;
len = sizeof(cliaddr); //len is value/resuslt
n = recvfrom(sockfd, (char*) buffer, MAXLINE,
MSG_WAITALL, (struct sockaddr *) &cliaddr, &len);
buffer[n] = '\0';
char c;
while (buffer[c] != '\0')
{
char ch = buffer[c];
if (ch >= 'A' && ch <= 'Z')
buffer[c] = buffer[c] + 32;
else if (ch >= 'a' && ch <= 'z')
buffer[c] = buffer[c] - 32;
c++;
}
//Returning Encrypted String Received By Client
sendto(sockfd, (const char *) buffer, strlen(buffer),
MSG_CONFIRM, (const struct sockaddr *) &cliaddr, len);
close(sockfd);
return 0;
}
这是我的输出:!(https://i.stack.imgur.com/uz7RY.png)!(https://i.stack.imgur.com/nuSI0.png)
它应该是这样的:!(https://i.stack.imgur.com/JnIFn.png)
服务器必须能够响应多个连续的客户端请求并执行直到显式退出 (^-C)。客户端应处理单个请求,然后在完成时退出。
我应该如何做对?
解决方案
您应该从 开始argv[1]
,因为argv[0]
是程序名称,而不是参数。
for (int i = 1; i < argc; i++) {
sendto(sockfd, argv[i], strlen(argv[i]),
MSG_CONFIRM, (const struct sockaddr *) &servaddr,
sizeof(servaddr));
}
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