C++ send file and text via socket - c++

Question

Im trying to send a image using socket but I have to send the file name as well. Im using a code that i send the file but when I send the file name i receive some strange characters in client.
Client:
#define PORT 20000
#define LENGTH 512
int main(int argc, char *argv[]){
int sockfd;
int nsockfd;
char revbuf[LENGTH];
struct sockaddr_in remote_addr;
/* Get the Socket file descriptor */
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
fprintf(stderr, "ERROR: Failed to obtain Socket Descriptor! (errno = %d)\n",errno);
exit(1);
}
/* Fill the socket address struct */
remote_addr.sin_family = AF_INET;
remote_addr.sin_port = htons(PORT);
inet_pton(AF_INET, "127.0.0.1", &remote_addr.sin_addr);
bzero(&(remote_addr.sin_zero), 8);
/* Try to connect the remote */
if (connect(sockfd, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) == -1)
{
fprintf(stderr, "ERROR: Failed to connect to the host! (errno = %d)\n",errno);
exit(1);
}
else
printf("[Client] Connected to server at port %d...ok!\n", PORT);
/* Send File to Server */
//if(!fork())
//{
char* fs_name = "house.jpg";
char sdbuf[LENGTH];
char buffer[256];
int n;
fgets(buffer,255,stdin);
bzero(buffer,256);
n = write(sockfd,buffer, strlen(buffer));
if(n<0) printf("Error: sending filename");
printf("[Client] Sending %s to the Server... ", fs_name);
FILE *fs = fopen(fs_name, "r");
if(fs == NULL)
{
printf("ERROR: File %s not found.\n", fs_name);
exit(1);
}
bzero(sdbuf, LENGTH);
int fs_block_sz;
while((fs_block_sz = fread(sdbuf, sizeof(char), LENGTH, fs)) > 0)
{
if(send(sockfd, sdbuf, fs_block_sz, 0) < 0)
{
fprintf(stderr, "ERROR: Failed to send file %s. (errno = %d)\n", fs_name, errno);
break;
}
bzero(sdbuf, LENGTH);
}
printf("Ok File %s from Client was Sent!\n", fs_name);
//}
close (sockfd);
printf("[Client] Connection lost.\n");
return (0);
}
Part of client that sends the text:
char buffer[256];
int n;
fgets(buffer,255,stdin);
bzero(buffer,256);
n = write(sockfd,buffer, strlen(buffer));
if(n<0) printf("Error: sending filename");
Server:
#define PORT 20000
#define BACKLOG 5
#define LENGTH 512
int main ()
{
int sockfd;
int nsockfd;
int num;
int sin_size;
struct sockaddr_in addr_local; /* client addr */
struct sockaddr_in addr_remote; /* server addr */
char revbuf[LENGTH];
/* Get the Socket file descriptor */
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 )
{
fprintf(stderr, "ERROR: Failed to obtain Socket Descriptor. (errno = %d)\n", errno);
exit(1);
}
else
printf("[Server] Obtaining socket descriptor successfully.\n");
/* Fill the client socket address struct */
addr_local.sin_family = AF_INET; // Protocol Family
addr_local.sin_port = htons(PORT); // Port number
addr_local.sin_addr.s_addr = INADDR_ANY; // AutoFill local address
bzero(&(addr_local.sin_zero), 8); // Flush the rest of struct
/* Bind a special Port */
if( bind(sockfd, (struct sockaddr*)&addr_local, sizeof(struct sockaddr)) == -1 )
{
fprintf(stderr, "ERROR: Failed to bind Port. (errno = %d)\n", errno);
exit(1);
}
else
printf("[Server] Binded tcp port %d in addr 127.0.0.1 sucessfully.\n",PORT);
/* Listen remote connect/calling */
if(listen(sockfd,BACKLOG) == -1)
{
fprintf(stderr, "ERROR: Failed to listen Port. (errno = %d)\n", errno);
exit(1);
}
else
printf ("[Server] Listening the port %d successfully.\n", PORT);
int success = 0;
while(success == 0)
{
sin_size = sizeof(struct sockaddr_in);
/* Wait a connection, and obtain a new socket file despriptor for single connection */
if ((nsockfd = accept(sockfd, (struct sockaddr *)&addr_remote, &sin_size)) == -1)
{
fprintf(stderr, "ERROR: Obtaining new Socket Despcritor. (errno = %d)\n", errno);
exit(1);
}
else
printf("[Server] Server has got connected from %s.\n", inet_ntoa(addr_remote.sin_addr));
char buffer[256];
bzero(buffer,256);
int n = 0;
n = read(nsockfd, buffer, 255);
if (n < 0) error("ERROR reading from socket");
printf("msg: %s\n",buffer);
/*Receive File from Client */
char* fr_name = "/house.jpg";
FILE *fr = fopen(fr_name, "a");
if(fr == NULL)
printf("File %s Cannot be opened file on server.\n", fr_name);
else
{
bzero(revbuf, LENGTH);
int fr_block_sz = 0;
while((fr_block_sz = recv(nsockfd, revbuf, LENGTH, 0)) > 0)
{
int write_sz = fwrite(revbuf, sizeof(char), fr_block_sz, fr);
if(write_sz < fr_block_sz)
{
error("File write failed on server.\n");
}
bzero(revbuf, LENGTH);
if (fr_block_sz == 0 || fr_block_sz != 512)
{
break;
}
}
if(fr_block_sz < 0)
{
if (errno == EAGAIN)
{
printf("recv() timed out.\n");
}
else
{
fprintf(stderr, "recv() failed due to errno = %d\n", errno);
exit(1);
}
}
printf("Ok received from client!\n");
fclose(fr);
}
}
}
Part of server that receive the text:
char buffer[256];
bzero(buffer,256);
int n = 0;
n = read(nsockfd, buffer, 255);
if (n < 0) error("ERROR reading from socket");
printf("msg: %s\n",buffer);
Need some help with that. Thanks...

Answer 1

In this code in your client:
char buffer[256];
int n;
fgets(buffer,255,stdin);
bzero(buffer,256);
n = write(sockfd,buffer, strlen(buffer));
It looks like you are trying to read the file name from the stdin and send it on the sockfd. But. you zero out the buffer before you send it.