Socket Programming in C - Sending a file from Server to Client - c

Question

I have socket code and client code below. So far all that it does is establish connection with the server, but I want it to also send a file from the client to the server; even if the file has no data in it. What do I have to do to augment this code to send files? Any suggestions in code form?
Client:
#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>
int main(int argc, char *argv[])
{
int sockfd = 0, n = 0;
char recvBuff[1024];
struct sockaddr_in serv_addr;
if(argc != 2)
{
printf("\n Usage: %s <ip of server> \n",argv[0]);
return 1;
}
memset(recvBuff, '0',sizeof(recvBuff));
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
printf("\n Error : Could not create socket \n");
return 1;
}
memset(&serv_addr, '0', sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(5000);
if(inet_pton(AF_INET, argv[1], &serv_addr.sin_addr)<=0)
{
printf("\n inet_pton error occured\n");
return 1;
}
if( connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
{
printf("\n Error : Connect Failed \n");
return 1;
}
while ( (n = read(sockfd, recvBuff, sizeof(recvBuff)-1)) > 0)
{
recvBuff[n] = 0;
if(fputs(recvBuff, stdout) == EOF)
{
printf("\n Error : Fputs error\n");
}
}
if(n < 0)
{
printf("\n Read error \n");
}
return 0;
}
Server:
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <time.h>
int main(int argc, char *argv[])
{
int listenfd = 0, connfd = 0;
struct sockaddr_in serv_addr;
char sendBuff[1025];
time_t ticks;
listenfd = socket(AF_INET, SOCK_STREAM, 0);
memset(&serv_addr, '0', sizeof(serv_addr));
memset(sendBuff, '0', sizeof(sendBuff));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(5000);
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
listen(listenfd, 10);
while(1)
{
connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);
ticks = time(NULL);
snprintf(sendBuff, sizeof(sendBuff), "%.24s\r\n", ctime(&ticks));
write(connfd, sendBuff, strlen(sendBuff));
close(connfd);
sleep(1);
}
}

Answer 1

I havn't tried compiling this, and this code is certainly not polished but something similar to below will do the trick :)
Modify the client end to look like this:
if( connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
{
printf("\n Error : Connect Failed \n");
return 1;
}
FILE *inputFile = fopen("inputFile.txt", "rb");
if(inputFile == NULL)
{
fprintf(stderr, "oh no!");
return 1;
}
char sendBuffer[10];
// TODO: Check for errors here
int bytesRead = fread(sendBuffer, sizeof(sendBuffer), 1, inputFile);
while(!feof(inputFile))
{
//TODO: check for errors here
send(sockfd, sendBuffer, bytesRead, 0);
bytesRead = fread(sendBuffer, sizeof(sendBuffer), 1, inputFile);
}
close(sockfd);
Modify the server end to look like this:
listen(listenfd, 10);
FILE *outputFile = fopen("output.txt", "wb");
if(outputFile == null)
{
fprintf(stderr, "Something went south!");
return 1;
}
while(1)
{
connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);
char recvBuff[10];
ticks = time(NULL);
int bytesReceived = recv(confd, recvBuff, 10, 0);
while(bytesReceived != 0)
{
// you should add error checking here
fwrite(recvBuff, bytesReceived, 1, outputFile);
bytesReceived = recv(confd, recvBuff, 10, 0);
}
close(connfd);
}