Question

我有此客户端和服务器程序。我正在尝试添加一个历史命令，当您在命令行中键入“历史”时，它会显示最近的10条命令，但是我遇到了问题，根本无法显示，但我不确定为什么它不会工作。键入“历史记录”后，它将不会显示任何内容，也无法键入任何命令，这之后我不得不重新启动代码才能键入unix命令。该程序通过发送诸如“ ls”之类的unix命令来工作或“日期”，它将信息从服务器发送回客户端。可能是因为我的代码有点bug，但它仍然可以正常工作。谁能指出我正确的方向？

客户：

Invalid 'X-Frame-Options' header encountered when loading 'https://cross-domain-services.firebaseapp.com/auth': 'ALLOW-FROM http://localhost:4200/' is not a recognized directive. The header will be ignored.

服务器：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define BUFFSIZE 2048

char history[10][50];
int historyCounter = 0;

char *encryptedMessage(char command[]){
    int i = 0;

    while (command[i] != '\0'){
        command[i] += 5;
        i += 1;
    }

    return command;
}



int main(int argc, char *argv[]){
    /*Created variables for socket, server address, arguement size, and a buffer*/
    int clientSocket, ret, portnum;
    struct sockaddr_in serverAddr;
    int received = 0;
    unsigned int echolen;
    char buffer[BUFFSIZE];

    /*If there is less than 3 arguments, print out a statement explaining to execute program
    along witjh server ip and port*/
    if(argc < 3){
        fprintf(stderr,"usage %s <server-ip-addr> <server-port>\n", argv[0]);
        exit(0);
    }
    /*Convert port number from the commandline using atoi*/
    portnum = atoi(argv[2]);

    /*Create socket, and check if there is an error in the connection*/
    clientSocket = socket(AF_INET, SOCK_STREAM, 0);
    if(clientSocket < 0){
        printf("Error in connection.\n");
        exit(1);
    }
    printf("Client Socket is created.\n");
    /*Memset server address*/
    memset(&serverAddr, '\0', sizeof(serverAddr));
    // memset(&buffer, '\0', sizeof(buffer));
    // serverAddr.sin_family = AF_INET;
    // serverAddr.sin_port = htons(PORT);
    // serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");

    // bzero((char *) &serverAddr, sizeof(serverAddr));

    /*Take ip address from commandline and set it into serverAddr*/
    serverAddr.sin_family = AF_INET;
    if(!inet_aton(argv[1], &serverAddr.sin_addr)){
        fprintf(stderr, "Error invalid server IP address\n");
        exit(1);
    }
    /*Take the port number and set it in the sin_port for connection*/
    serverAddr.sin_port = htons(portnum);
    /*Connect the client to the server, if less than 0, then there is an error in the connection*/
    ret = connect(clientSocket, (struct sockaddr*)&serverAddr, sizeof(serverAddr));
    if(ret < 0){
        printf("Error in connection.\n");
        exit(1);
    }
    printf("Connected to server.\n");
    /*Initialize argument buffer*/
    char s[100];
    /*In the while loop we take the arguments after we connect and put them in stdin, we insert \0 at the
    end of s array*/
    while(1){
        int _switch = 0;
        fgets(s, 100, stdin);
        historyCounter++;
        //s[strlen(s)-1]='\0';
        echolen = strlen(s);
        if(historyCounter < 10){
            for(int i = 0; i < historyCounter; i++){
                strcpy(history[i+1], history[i]);
            }
        }
        strcpy(history[0], s);

        /*  send() from client, if it doesn't equal echolen then show it failed */
        if(strcmp(s,"history") == 0){
            _switch = 1;
            int a = 0;
            int b = 0;

            for (int a = 0; a < historyCounter; a++){
                printf("%d", historyCounter);
                while(history[a][b] != '\0'){
                    printf("%c", history[a][b]);
                    b++;
                }
                b = 0;
                printf("\n");
            }
            printf("\n");

        }


        if(_switch == 0){
            if (send(clientSocket, s, echolen, 0) != echolen)
        {
            printf("Failed");
        }

        if(strcmp(s,"quit") == 0) //check if exit is typed
            exit(0);
        fprintf(stdout, "Message from server: ");
        //fprintf(stdin, "%s\n", s);
        while (received < echolen)
        {
            ssize_t bytes = 0;
            /* recv() from server, the bytes we receive are from the clientSocket */
            if ((bytes = recv(clientSocket, buffer, echolen, 0)) < 1)
            {
                printf("Failed to get Information");
            }
            received += bytes;
            buffer[bytes] = '\0';
            /*WE receive the information and print in stdout what's in the buffer*/
            fprintf(stdout, buffer);
        }
        ssize_t bytes = 0;
        /*Place /0 at end of the buffer*/
        do {
            buffer[bytes] = '\0';
            printf("%s\n", buffer);
        } while((bytes = recv(clientSocket, buffer, BUFFSIZE-1, 0))>=BUFFSIZE-1);
        buffer[bytes] = '\0';
        printf("%s\n", buffer);
        printf("\n");
        }

        /*Above is essentially printing out the information within the buffer from the recv()*/

    }
}

Answer 1

fgets（）读取直到换行符，但还在输入缓冲区的末尾复制该换行符。在用于历史记录命令的strcmp（）中，它可能会失败。请检查fgets（）的手册页。

将历史记录命令添加到多客户端服务器程序

1 个答案: