本文所述示例程序是基于Linux平臺的socket網絡編程，實現文件傳輸功能。該示例是基于TCP流協議實現的socket網絡文件傳輸程序。采用C語言編寫。最終能夠實現傳輸任何格式文件的文件傳輸程序。
具體實現代碼如下：
Server端代碼如下：
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/************************************************************************* > File Name: Server.c > Author: SongLee ************************************************************************/ #include<netinet/in.h> // sockaddr_in #include<sys/types.h> // socket #include<sys/socket.h> // socket #include<stdio.h> // printf #include<stdlib.h> // exit #include<string.h> // bzero #define SERVER_PORT 8000 #define LENGTH_OF_LISTEN_QUEUE 20 #define BUFFER_SIZE 1024 #define FILE_NAME_MAX_SIZE 512 int main(void) { // 聲明并初始化一個服務器端的socket地址結構 struct sockaddr_in server_addr; bzero(&server_addr, sizeof(server_addr)); server_addr.sin_family = AF_INET; server_addr.sin_addr.s_addr = htons(INADDR_ANY); server_addr.sin_port = htons(SERVER_PORT); // 創建socket，若成功，返回socket描述符 int server_socket_fd = socket(PF_INET, SOCK_STREAM, 0); if(server_socket_fd < 0) { perror("Create Socket Failed:"); exit(1); } int opt = 1; setsockopt(server_socket_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)); // 綁定socket和socket地址結構 if(-1 == (bind(server_socket_fd, (struct sockaddr*)&server_addr, sizeof(server_addr)))) { perror("Server Bind Failed:"); exit(1); } // socket監聽 if(-1 == (listen(server_socket_fd, LENGTH_OF_LISTEN_QUEUE))) { perror("Server Listen Failed:"); exit(1); } while(1) { // 定義客戶端的socket地址結構 struct sockaddr_in client_addr; socklen_t client_addr_length = sizeof(client_addr); // 接受連接請求，返回一個新的socket(描述符)，這個新socket用于同連接的客戶端通信 // accept函數會把連接到的客戶端信息寫到client_addr中 int new_server_socket_fd = accept(server_socket_fd, (struct sockaddr*)&client_addr, &client_addr_length); if(new_server_socket_fd < 0) { perror("Server Accept Failed:"); break; } // recv函數接收數據到緩沖區buffer中 char buffer[BUFFER_SIZE]; bzero(buffer, BUFFER_SIZE); if(recv(new_server_socket_fd, buffer, BUFFER_SIZE, 0) < 0) { perror("Server Recieve Data Failed:"); break; } // 然后從buffer(緩沖區)拷貝到file_name中 char file_name[FILE_NAME_MAX_SIZE+1]; bzero(file_name, FILE_NAME_MAX_SIZE+1); strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE?FILE_NAME_MAX_SIZE:strlen(buffer)); printf("%s\n", file_name); // 打開文件并讀取文件數據 FILE *fp = fopen(file_name, "r"); if(NULL == fp) { printf("File:%s Not Found\n", file_name); } else { bzero(buffer, BUFFER_SIZE); int length = 0; // 每讀取一段數據，便將其發送給客戶端，循環直到文件讀完為止 while((length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0) { if(send(new_server_socket_fd, buffer, length, 0) < 0) { printf("Send File:%s Failed./n", file_name); break; } bzero(buffer, BUFFER_SIZE); } // 關閉文件 fclose(fp); printf("File:%s Transfer Successful!\n", file_name); } // 關閉與客戶端的連接 close(new_server_socket_fd); } // 關閉監聽用的socket close(server_socket_fd); return 0; } |
Client端代碼如下：
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/************************************************************************* > File Name: Client.c > Author: SongLee ************************************************************************/ #include<netinet/in.h> // sockaddr_in #include<sys/types.h> // socket #include<sys/socket.h> // socket #include<stdio.h> // printf #include<stdlib.h> // exit #include<string.h> // bzero #define SERVER_PORT 8000 #define BUFFER_SIZE 1024 #define FILE_NAME_MAX_SIZE 512 int main() { // 聲明并初始化一個客戶端的socket地址結構 struct sockaddr_in client_addr; bzero(&client_addr, sizeof(client_addr)); client_addr.sin_family = AF_INET; client_addr.sin_addr.s_addr = htons(INADDR_ANY); client_addr.sin_port = htons(0); // 創建socket，若成功，返回socket描述符 int client_socket_fd = socket(AF_INET, SOCK_STREAM, 0); if(client_socket_fd < 0) { perror("Create Socket Failed:"); exit(1); } // 綁定客戶端的socket和客戶端的socket地址結構 非必需 if(-1 == (bind(client_socket_fd, (struct sockaddr*)&client_addr, sizeof(client_addr)))) { perror("Client Bind Failed:"); exit(1); } // 聲明一個服務器端的socket地址結構，并用服務器那邊的IP地址及端口對其進行初始化，用于后面的連接 struct sockaddr_in server_addr; bzero(&server_addr, sizeof(server_addr)); server_addr.sin_family = AF_INET; if(inet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr) == 0) { perror("Server IP Address Error:"); exit(1); } server_addr.sin_port = htons(SERVER_PORT); socklen_t server_addr_length = sizeof(server_addr); // 向服務器發起連接，連接成功后client_socket_fd代表了客戶端和服務器的一個socket連接 if(connect(client_socket_fd, (struct sockaddr*)&server_addr, server_addr_length) < 0) { perror("Can Not Connect To Server IP:"); exit(0); } // 輸入文件名 并放到緩沖區buffer中等待發送 char file_name[FILE_NAME_MAX_SIZE+1]; bzero(file_name, FILE_NAME_MAX_SIZE+1); printf("Please Input File Name On Server:\t"); scanf("%s", file_name); char buffer[BUFFER_SIZE]; bzero(buffer, BUFFER_SIZE); strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE?BUFFER_SIZE:strlen(file_name)); // 向服務器發送buffer中的數據 if(send(client_socket_fd, buffer, BUFFER_SIZE, 0) < 0) { perror("Send File Name Failed:"); exit(1); } // 打開文件，準備寫入 FILE *fp = fopen(file_name, "w"); if(NULL == fp) { printf("File:\t%s Can Not Open To Write\n", file_name); exit(1); } // 從服務器接收數據到buffer中 // 每接收一段數據，便將其寫入文件中，循環直到文件接收完并寫完為止 bzero(buffer, BUFFER_SIZE); int length = 0; while((length = recv(client_socket_fd, buffer, BUFFER_SIZE, 0)) > 0) { if(fwrite(buffer, sizeof(char), length, fp) < length) { printf("File:\t%s Write Failed\n", file_name); break; } bzero(buffer, BUFFER_SIZE); } // 接收成功后，關閉文件，關閉socket printf("Receive File:\t%s From Server IP Successful!\n", file_name); close(fp); close(client_socket_fd); return 0; } |
該程序備有較為詳盡的注釋，相信不難理解。感興趣的朋友可以在此基礎上嘗試一些功能的擴展，使其功能更加強大。
