c - 如何使用客户端、服务器-客户端、套接字编码、使用 C 显示相机馈送？ (Linux)

#define _GNU_SOURCE -D #include <in.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <errno.h> #include <unistd.h> #include <arpa/inet.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <sys/time.h> #include <syslog.h> #include <capture.h> #include <sys/sendfile.h> #include <pthread.h> //define where the network camera is located #define PORT_NUMBER 1025 #define SERVER_ADDRESS "localhost" void *msg_handler(void *); //step 1 /* The server is supposed to send a list of available resolutions and frames per second, so the client can choose*/ //we create a handler to each client void *client_handler(int server_socket) { int serverSocket = *(int *)server_socket; // this is a pointer to the server socket char *message, cli_message[2000]; message = capture_get_resolutions_list(0); //list of available image resolutions; write(serverSocket, message, strlen(message)); //send to client the list of resolutions write(serverSocket, "\n", strlen("\n")); //breaking line so the client can see the list memset(message, 0, strlen(message)); //resetting the message variable //variables related to the image media_stream *imageStream; recv(serverSocket, cli_message, 2000, 0); // receive information from client regarding resolution media_frame *imageFrame; void *data; size_t imageSize; int arrayRow = 0; //related to the data array - we need it if we want to loop later through the array //opening the stream in order to capture image imageStream = capture_open_stream(IMAGE_JPEG, cli_message); //send image to client with chosen resolution while (1) //condition always true, i.e. infinite loop { imageFrame = capture_get_frame(imageStream); data = capture_frame_data(imageFrame); imageSize = capture_frame_size(imageFrame); sprintf(message, "%zu\n", imageSize); //converting the size to a char , and send to client write(serverSocket, message, strlen(message)); //sending the size to the client unsigned char arrayRow_data[imageSize]; for (arrayRow = 0; arrayRow < imageSize; arrayRow++) { arrayRow_data[arrayRow] = ((unsigned char *)data)[arrayRow]; } //try to send data to client ---> see the possible errors int sendDataError = write(serverSocket, arrayRow_data, sizeof(arrayRow_data)); if (sendDataError < 0) { syslog(LOG_INFO, "oops, connection with client lost"); break; } //restoring variables to ZERO memset(data, 0, sizeof(data)); memset(arrayRow_data, 0, sizeof(arrayRow_data)); capture_frame_free(imageFrame); } syslog(LOG_INFO, "ERROR:CAN NOT SEND IMAGE"); capture_close_stream(imageStream); close(serverSocket); return 0; } //main function //creating a socket int main(void) { //char server_message[256]= "Congrats, you have reached the server"; int server_socket; int client_socket; int *new_socket; int conn; struct sockaddr_in server, client; server_socket = socket(AF_INET, SOCK_STREAM, 0); server.sin_family = AF_INET; server.sin_addr.s_addr = INADDR_ANY; server.sin_port = htons(1025); //bind the socket to the specified IP and port bind(server_socket, (struct sockaddr *)&server, sizeof(server)); conn = sizeof(struct sockaddr_in); listen(server_socket, 5); //accept the connection from the client and send the message while ((client_socket = accept(server_socket, (struct sockaddr *)&client, (socklen_t *)&conn))) { pthread_t client_thread; new_socket = malloc(sizeof *new_socket); new_socket = client_socket; //establishing a message thread and possible errors if (pthread_create(&client_thread, NULL, client_handler, (void *)new_socket) < 0) { syslog(LOG_INFO, "ERROR. MESSAGE THREAD NOT ESTABLISHED"); return 1; } } if (client_socket < 0) { syslog(LOG_INFO, "Sorry, client socket declined"); free(new_socket); return 1; } return 0; }

#include <sys/socket.h> #include <sys/types.h> #include <netinet/in.h> #include <netdb.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <errno.h> #include <arpa/inet.h> //The port this client will connect to: #define PORT 1025 //Set MAX number of bytes the client can recieve //at a time. #define MAXDATASIZE 2000 //Main method int main (int argc, char *argv[]) { //Variables int sockfd, numbytes; char buf[MAXDATASIZE]; struct hostent *he; //Connector's address information struct sockaddr_in their_addr; //Get the HOST-info if((he = gethostbyname(argv[1])) == NULL) { //No host? ERROR. perror("gethostbyname()"); exit(1); } else { //Print the HOST-data. printf("Client-The remote host is: %s\n", argv[1]); } //Check for socket if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { //Socket error? perror("socket()"); exit(1); } else { //Print socket-is-OK status. printf("Client-The socket() sockfd is OK...\n"); } //Host byte order their_addr.sin_family = AF_INET; //Short, network byte order printf("Server-Using %s and port %d...\n", argv[1], PORT); their_addr.sin_port = htons(PORT); their_addr.sin_addr = *((struct in_addr*)he->h_addr); //Zero the rest of the struct memset(&(their_addr.sin_zero), '\0', 8); //Is everything still OK with the connection...? if(connect(sockfd, (struct sockaddr *)&their_addr, sizeof(struct sockaddr)) == -1) { //Connection error! perror("connect()"); exit(1); } else { printf("Client-The connect() is OK... \n"); } //Data recieved? if((numbytes = recv(sockfd, buf, MAXDATASIZE - 1, 0)) == -1) { //Error recieving perror("recv()"); exit(1); } else { //Data recieved OK! printf("Client-The recv() is OK... \n"); } //Deal with recieved data, print recieved data. buf[numbytes] = '\0'; printf("Client-Recieved: %s", buf); printf("Client-No more data. Closing sockfd.\n"); close(sockfd); return 0; }