Anonymous user
Chat server: Difference between revisions
Add C example.
(Add C example.) |
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end loop;
end Chat_Server;</lang>
=={{header|C}}==
C has no built-in networking functions, but the POSIX library does provide some low-level networking functions. The functions of interest relating to sockets include ''bind'', ''listen'', ''select'', ''accept'', ''read'', ''write'' and ''close''.
The example below was compiled on Cygwin, and accepts PuTTY connections under the RAW protocol.
A glitch occurs if a connection is made using the Telnet protocol - user names are preceded by garbled text.
<lang c>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <netinet/ip.h>
int tsocket;
struct sockaddr_in tsockinfo;
fd_set status, current;
void ClientText(int handle, char *buf, int buf_len);
struct client
{
char buffer[4096];
int pos;
char name[32];
} *connections[FD_SETSIZE];
void AddConnection(int handle)
{
connections[handle] = malloc(sizeof(struct client));
connections[handle]->buffer[0]='\0';
connections[handle]->pos=0;
connections[handle]->name[0]='\0';
}
void CloseConnection(int handle)
{
char buf[512];
int j;
FD_CLR(handle, &status);
if (connections[handle]->name[0])
{
sprintf(buf, "* Disconnected: %s\r\n", connections[handle]->name);
for (j=0; j<FD_SETSIZE; j++)
{
if (handle !=j && j!=tsocket && FD_ISSET(j, &status))
{
if (write(j, buf, strlen(buf))<0)
{
CloseConnection(j);
}
}
}
} else
{
printf ("-- Connection %d disconnected\n", handle);
}
if (connections[handle])
{
free(connections[handle]);
}
close(handle);
}
void strip(char *buf)
{
char *x;
x=strchr(buf, '\n');
if (x) {*x='\0';}
x=strchr(buf, '\r');
if (x) {*x='\0';}
}
int RelayText(int handle)
{
char *begin, *end;
int ret=0;
begin = connections[handle]->buffer;
if (connections[handle]->pos==4000)
{
if (begin[3999]!='\n')
begin[4000]='\0';
else {
begin[4000]='\n';
begin[4001]='\0';
}
} else {
begin[connections[handle]->pos]='\0';
}
end = strchr(begin, '\n');
while (end!=NULL)
{
char output[8000];
output[0]='\0';
if (!connections[handle]->name[0])
{
strncpy(connections[handle]->name, begin, 31);
connections[handle]->name[31]='\0';
strip(connections[handle]->name);
sprintf(output, "* Connected: %s\r\n", connections[handle]->name);
ret=1;
} else
{
sprintf (output, "%s: %.*s\r\n", connections[handle]->name,
end-begin, begin);
ret=1;
}
if (output[0])
{
int j;
for (j=0; j<FD_SETSIZE; j++)
{
if (handle !=j && j!=tsocket && FD_ISSET(j, &status))
{
if (write(j, output, strlen(output))<0)
{
CloseConnection(j);
}
}
}
}
begin=end+1;
end = strchr(begin, '\n');
}
strcpy(connections[handle]->buffer, begin);
connections[handle]->pos -= begin - connections[handle]->buffer;
return ret;
}
void ClientText(int handle, char *buf, int buf_len)
{
int i,j;
if (!connections[handle])
return;
j=connections[handle]->pos;
for (i=0; i<buf_len; ++i, ++j)
{
connections[handle]->buffer[j]=buf[i];
if (j==4000)
{
while (RelayText(handle));
j=connections[handle]->pos;
}
}
connections[handle]->pos = j;
while (RelayText(handle));
}
int ChatLoop()
{
int i,j;
FD_ZERO(&status);
FD_SET(tsocket, &status);
FD_SET(0, &status);
while(1)
{
current=status;
if (select(FD_SETSIZE, ¤t, NULL, NULL, NULL)==-1)
{
perror("Select");
return 0;
}
for (i=0; i<FD_SETSIZE; ++i)
{
if (FD_ISSET(i, ¤t))
{
if (i==tsocket)
{
struct sockaddr_in cliinfo;
socklen_t addrlen = sizeof(cliinfo);
int handle;
handle=accept(tsocket, &cliinfo, &addrlen);
if (handle==-1)
{
perror ("Couldn't accept connection");
} else if (handle>FD_SETSIZE)
{
printf ("Unable to accept new connection.\n");
close(handle);
}
else
{
if (write(handle, "Enter name: ", 12)>=0)
{
printf ("-- New connection %d from %s:%hu\n",
handle,
inet_ntoa (cliinfo.sin_addr),
ntohs(cliinfo.sin_port));
FD_SET(handle, &status);
AddConnection(handle);
}
}
} /* Read data, relay to others. */
else
{
char buf[512];
int b;
b=read(i, buf, 500);
if (b<=0)
{
CloseConnection(i);
}
else
{
ClientText(i, buf, b);
}
}
}
}
} /* While 1 */
}
int main (int argc, char*argv[])
{
tsocket = socket(PF_INET, SOCK_STREAM, 0);
tsockinfo.sin_family=AF_INET;
tsockinfo.sin_port=htons(7070);
if (argc>1)
{
tsockinfo.sin_port = htons(atoi(argv[1]));
}
tsockinfo.sin_addr.s_addr = htonl(INADDR_ANY);
printf ("Socket %d on port %hu\n", tsocket, ntohs(tsockinfo.sin_port));
if (bind (tsocket, &tsockinfo, sizeof(tsockinfo))==-1)
{
perror("Couldn't bind socket");
return -1;
}
if (listen(tsocket, 10)==-1)
{
perror("Couldn't listen to port");
}
ChatLoop();
return 0;
}
</lang>
=={{header|CoffeeScript}}==
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