我尝试使用TCP / IP在C中实现客户端和服务器，以便使用套接字发送消息和文件。邮件已发送但文件内容无效。我想从服务器向客户端发送文件，在客户端创建文件，但是来自服务器的文件内容不会传输到客户端。 在客户端等待消息时，如果消息包含“GET_FILE a.txt”，则服务器将文件a.txt发送到客户端，如果输入其他文本，则这是一条简单消息。 因此，如果运行客户端并键入消息“GET_FILE nameOfFile”，则服务器需要返回此文件，如果键入其他消息服务器则需要返回消息。
这是我的服务器代码：
this这是客户端代码：
#include <stdio.h>
#include <string.h> //strlen
#include <stdlib.h> //strlen
#include <sys/socket.h>
#include <arpa/inet.h> //inet_addr
#include <unistd.h> //write
#include <pthread.h> //for threading , link with lpthread
//the thread function
void *connection_handler(void *);
void *SendFileToClient(int*);
pthread_t tid;
int main(int argc , char *argv[])
{
int socket_desc , client_sock , c , *new_sock;
struct sockaddr_in server , client;
//Create socket
socket_desc = socket(AF_INET , SOCK_STREAM , 0);
if (socket_desc == -1)
{
printf("Could not create socket");
}
puts("Socket created");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 8888 );
// printf("!!!!!!!%s", server.sin_addr.s_addr);
//Bind
if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
{
//print the error message
perror("bind failed. Error");
return 1;
}
puts("bind done");
//Listen
listen(socket_desc , 3);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while( (client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)) )
{
puts("Connection accepted");
pthread_t sniffer_thread;
new_sock = malloc(1);
*new_sock = client_sock;
if( pthread_create( &sniffer_thread , NULL , connection_handler , (void*) new_sock) < 0)
{
perror("could not create thread");
return 1;
}
//Now join the thread , so that we dont terminate before the thread
//pthread_join( sniffer_thread , NULL);
puts("Handler assigned");
}
if (client_sock < 0)
{
perror("accept failed");
return 1;
}
return 0;
}
/*
* This will handle connection for each client
* */
void *connection_handler(void *socket_desc)
{
//Get the socket descriptor
int sock = *(int*)socket_desc;
int read_size;
int err;
int i = 0, j = 0;
char *message , client_message[2000], file_name[2000];
//Receive a message from client
while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 )
{
//Send the message back to client
if(strncmp(client_message, "GET_FILE ", 8) == 0)
{
for(i = 9; i < strlen(client_message); i++){
file_name[j] = client_message[i];
j++;
}
err = pthread_create(&tid, NULL, &SendFileToClient, &file_name);
if (err != 0)
printf("\ncan't create thread :[%s]", strerror(err));
}
else
{
write(sock , client_message , strlen(client_message));
}
}
if(read_size == 0)
{
puts("Client disconnected");
fflush(stdout);
}
else if(read_size == -1)
{
perror("recv failed");
}
//Free the socket pointer
free(socket_desc);
return 0;
}
void* SendFileToClient(int* file_name){
int connfd = (int)*file_name;
printf("Connection accepted and id: %d\n",connfd);
printf("Connected to Client: %s:%d\n", "127.0.0.1", 8888);
//write(connfd, file_name,256);
FILE *fp = fopen(file_name,"rb");
if(fp==NULL)
{
printf("File opern error");
return 1;
}
/* Read data from file and send it */
while(1)
{
/* First read file in chunks of 256 bytes */
unsigned char buff[1024] = {0};
int nread = fread(buff, 1, 1024, fp);
//printf("Bytes read %d \n", nread);
/* If read was success, send data. */
if(nread > 0)
{
//printf("Sending \n");
write(connfd, buff, nread);
}
if (nread < 1024)
{
if (feof(fp))
{
printf("End of file\n");
printf("File transfer completed for id: %d\n", connfd);
}
if (ferror(fp)){
printf("Error reading\n");
break;
}
}
printf("Closing Connection for id: %d\n", connfd);
close(connfd);
shutdown(connfd, SHUT_WR);
sleep(2);
}
}
非常感谢你的帮助！
UPDATE !!!
我更新了服务器的代码，但现在我收到服务器的错误消息：“ 读错误 recv failed：错误的文件描述符 “
客户端代码相同，服务器代码现在是：
#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>
#include <stdio.h> //printf
#include <string.h> //strlen
#include <sys/socket.h> //socket
#include <arpa/inet.h> //inet_addr
void gotoxy(int x,int y)
{
printf("%c[%d;%df",0x1B,y,x);
}
int main(int argc , char *argv[])
{
int sock;
struct sockaddr_in server;
char message[1000] , server_reply[2000];
//Create socket
sock = socket(AF_INET , SOCK_STREAM , 0);
if (sock == -1)
{
printf("Could not create socket");
}
puts("Socket created");
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_family = AF_INET;
server.sin_port = htons( 8888 );
//Connect to remote server
if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
{
perror("connect failed. Error");
return 1;
}
puts("Connected\n");
//keep communicating with server
while(1)
{
char file_name[2000];
int i = 0, j = 0;
printf("Enter message : ");
//scanf("%s" , message);
gets(message);
//puts(message);
//printf("%d", strncmp(message, "GET_FILE ", 9) );
if(strncmp(message, "GET_FILE ", 8) == 0)
{
//Send some data
if( send(sock , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
for(i = 9; i < strlen(message); i++){
file_name[j] = message[i];
j++;
}
/* Create file where data will be stored */
FILE *fp;
int bytesReceived = 0;
char recvBuff[1024];
puts(file_name);
puts("Receiving file...");
fp = fopen(file_name, "ab");
if(NULL == fp)
{
printf("Error opening file");
return 1;
}
long double sz = 1;
/* Receive data in chunks of 256 bytes */
while((bytesReceived = read(sock, recvBuff, 1024)) > 0)
{
printf("%d", bytesReceived);
sz++;
gotoxy(0,4);
//printf("Received: %lf Mb",(sz/1024));
fflush(stdout);
// recvBuff[n] = 0;
fwrite(recvBuff, 1, bytesReceived, fp);
// printf("%s \n", recvBuff);
}
if(bytesReceived < 0)
{
printf("\n Read Error \n");
}
printf("\nFile OK....Completed\n");
}
else
{
//Send some data
if( send(sock , message , strlen(message) , 0) < 0)
{
puts("Send failed");
return 1;
}
//Receive a reply from the server
if( recv(sock , server_reply , 2000 , 0) < 0)
{
puts("recv failed");
break;
}
puts("Server reply :");
puts(server_reply);
}
}
close(sock);
return 0;
}