#include #include #include #include #include #include #include void fErrorExit(char * errStr) { fprintf(stderr, "\nError: %s\n", errStr); exit(-1); } int fMenue() { int rc = 0; do { fprintf(stdout, "\nHow should we reply?\n"); fprintf(stdout, "1 200 OK (with sample page)\n"); fprintf(stdout, "2 401 Unauthorized (with error report)\n"); fprintf(stdout, "3 404 Not found (with error report)\n"); fprintf(stdout, "4 501 Not implemented (with error report)\n"); fprintf(stdout, "5 500 Internal Server Error (with error report)\n"); fprintf(stdout, "6 close connection immediately\n"); fscanf(stdin, "%d", &rc); } while ((rc<1)||(rc>6)); return(rc); } int main(int argc, char* argv[]) { if (argc!=2) fErrorExit("usage: myWebServer port"); int portnum = atoi(argv[1]); int s; // socket if ((s=socket(PF_INET,SOCK_STREAM,0))<0) { fErrorExit("could not create socket"); } struct sockaddr_in sockAddr; sockAddr.sin_family = AF_INET; sockAddr.sin_port = htons(portnum); sockAddr.sin_addr.s_addr = INADDR_ANY; if (bind(s, (struct sockaddr *)&sockAddr, sizeof(sockAddr))<0) { fErrorExit("could not bind"); } int backlog = 8; if (listen(s, backlog)<0) fErrorExit("Could not listen"); unsigned int addrLen = sizeof(sockAddr); int t; // new socket to get from accept // Web server routine // wait for connection // serialized operation: only one connection can be accepted at one time while (true) { if ((t = accept(s, (struct sockaddr *)&sockAddr, &addrLen))<0) { fErrorExit("Could not accept connection"); } fprintf(stdout, "Connection from %s:%d.\n", inet_ntoa(sockAddr.sin_addr), ntohs(sockAddr.sin_port)); // get request string from client char msgStr[1024]; int nChar = 0; if ((nChar = read(t, msgStr, sizeof(msgStr)))>0) { // trim the string msgStr[nChar]='\0'; // cccc ------------------------------------------------------------- // cccc | currently this is an extremely simple hack that only works // cccc | with buffered input! // cccc | should search for CRLF sequence to detect commands instead // cccc ------------------------------------------------------------- fprintf(stdout, "received %d characters: \n'%s'\n", nChar, msgStr); // select reply string interactively from menue int m = fMenue(); switch(m) { case 1 : // 200 OK with sample page { char * replyStr = "HTTP/1.0 200 OK\n\n\nSample Page\n\n

Sample Page

This is a sample page with some sample text...\n\n"; if (write(t, replyStr, strlen(replyStr)) < 0) fErrorExit("Could not write echo string"); } break; case 2 : // 401 unauthorized { char * replyStr = "HTTP/1.0 401 Unauthorized\n\n\n401 Unauthorized Access\n\n

Unauthorized Access

You do not have sufficient privileges to access this page\n\n"; if (write(t, replyStr, strlen(replyStr)) < 0) fErrorExit("Could not write echo string"); } break; case 3 : // 404 not found with sample page { char * replyStr = "HTTP/1.0 404 Not Found\n\n\n404 Not Found\n\n

Not Found

The page you requested was not found on this server\n\n"; if (write(t, replyStr, strlen(replyStr)) < 0) fErrorExit("Could not write echo string"); } break; case 4 : // 501 not implemented with sample page { char * replyStr = "HTTP/1.0 501 Not Implemented\n\n\n501 Not Implemented\n\n

Not Implemented

The requested method is not implemented in this server.\n\n"; if (write(t, replyStr, strlen(replyStr)) < 0) fErrorExit("Could not write echo string"); } break; case 5 : // 500 internal server error with sample page { char * replyStr = "HTTP/1.0 500 Internal Server Error\n\n\nInternal Server Error\n\n

Sorry

Due to an internal error, this server was not able to fulfill your request.\n\n"; if (write(t, replyStr, strlen(replyStr)) < 0) fErrorExit("Could not write echo string"); } break; case 6 : default : // close connection immediately break; } } // close accepted socket if (close(t)<0) fErrorExit("Could not close accepted socket"); } // close original socket if (close(s)<0) fErrorExit("Could not close original socket"); return(0); }