Hi everybody, How can I rewrite the following code to use multiple threads to pr
ID: 3888206 • Letter: H
Question
Hi everybody,
How can I rewrite the following code to use multiple threads to process http requests?
Thank you!
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
#include <netinet/in.h>
#include <resolv.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <ctime>
#include <sys/types.h>
#include <sys/stat.h>
#include <pthread.h>
int host_port = 8080;
void usage()
{
printf("myhttpd, a simple webserver ");
printf("ver 1.0, 2014 ");
printf("Usage Summary: myhttpd -h -p portno -d ");
printf(" -h: display the summary ");
printf(" -p: change default port number for example: -p 8080 ");
}
void* httpHandler(void* socket)
{
char buffer[1024];
int buffer_len = 1024;
int bytecount;
int sock = *(int*)socket;
FILE* fp = fopen("Log.txt", "a");
time_t t = time(0);
struct tm * now = localtime( & t );
memset(buffer, 0, buffer_len);
if ((bytecount = recv(sock, buffer, buffer_len, 0))== -1)
{
fprintf(fp, "Error receiving data %d ", errno);
return 0;
}
fprintf(fp,"[REQUEST] Received at %d-%d-%d ", (now->tm_mon +1), (now->tm_mday), (now->tm_year + 1900));
fprintf(fp,"Received bytes %d Received string "%s" ", bytecount, buffer);
strcpy(buffer, "HTTP/1.1 200 OK Server: demo Content-Length: 37 Connection: close Content-Type: html <html><body>Welcome to my first page!</body></html>");
if ((bytecount = send(sock, buffer, strlen(buffer), 0))== -1)
{
fprintf(fp,"Error sending data %d ", errno);
return 0;
}
fprintf(fp,"Sent bytes %d ", bytecount);
//Close socket
close(sock);
//Clean-up logging
fflush(fp);
fclose(fp);
return 0;
}
int main(int argc, char *argv[])
{
struct sockaddr_in my_addr;
pid_t pid = 0;
pid_t sid = 0;
// Create child process
pid = fork();
if (pid < 0)
{
puts("[ERROR] Forking Failed! Exiting...");
exit(1);
}
// PARENT PROCESS. Need to kill it.
if (pid > 0)
{
printf("[SUCCESS] Process ID of child process is %d. Exiting main process. ", pid);
// return success in exit status
exit(0);
}
//set new session
sid = setsid();
if(sid < 0)
{
exit(1);
}
//No longer have a terminal, need to close these pipes
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
//Log for debuggin
FILE* fp = fopen ("Log.txt", "a");
fprintf(fp, " [DEBUG] *** SERVER STARTED *** [DEBUG] Logging Enabled. ");
fflush(fp);
fclose(fp);
int hsock;
int * p_int ;
int err;
int socketfd;
socklen_t addr_size = 0;
int* csock;
sockaddr_in sadr;
pthread_t thread_id=0;
int opt = 0;
opt = getopt( argc, argv,"dhl:p:r:t:n:s:" );
while (opt != -1)
{
switch (opt)
{
case 'h':
usage();
exit(0);
case 'p':
host_port = atoi(optarg);
break;
case 'r':
break;
}
opt = getopt( argc, argv, "dhl:p:r:t:n:s:" );
}
hsock = socket(AF_INET, SOCK_STREAM, 0);
if (hsock == -1)
{
printf("Error initializing socket %d ", errno);
exit(-1);
}
p_int = (int*)malloc(sizeof(int));
*p_int = 1;
if ((setsockopt(hsock, SOL_SOCKET, SO_REUSEADDR, (char*)p_int, sizeof(int)) == -1 )||
(setsockopt(hsock, SOL_SOCKET, SO_KEEPALIVE, (char*)p_int, sizeof(int)) == -1 ) )
{
printf("Error setting options %d ", errno);
free(p_int);
exit(-1);
}
free(p_int);
my_addr.sin_family = AF_INET ;
my_addr.sin_port = htons(host_port);
memset(&(my_addr.sin_zero), 0, 8);
my_addr.sin_addr.s_addr = INADDR_ANY ;
if (bind(hsock, (sockaddr*)&my_addr, sizeof(my_addr)) == -1 )
{
fprintf(stderr,"Error binding to socket, make sure nothing else is listening on this port %d ",errno);
exit(-1);
}
if (listen(hsock, 10) == -1 )
{
fprintf(stderr, "Error listening %d ",errno);
exit(-1);
}
//Now lets do the server stuff
printf("myhttpd server listening on port %d ", host_port);
addr_size = sizeof(sockaddr_in);
pthread_t tid;
while (true)
{
printf("waiting for a connection ");
if ((socketfd = accept( hsock, (sockaddr*)&sadr, &addr_size))!= -1)
{
printf("Received connection from %s - %d ",inet_ntoa(sadr.sin_addr), socketfd);
//httpHandler(socketfd);
//This code is for threading
int error = pthread_create(&tid, NULL, httpHandler, (void*) &socketfd);
//Debug code for development
if(error)
puts("ERROR: Problem creating thread.");
else
puts("SUCCESS: Thread created");
}
else
{
fprintf(stderr, "Error accepting %d ", errno);
}
}
close(socketfd);
}
Explanation / Answer
public class Background { static class CallableThread implements Callable { private HttpClient httpClient; private HttpGet httpGet; public CallableThread(HttpClient httpClient, HttpGet httpGet) { this.httpClient = httpClient; this.httpGet = httpGet; } @Override public ArrayList call() throws Exception { HttpResponse response = httpClient.execute(httpGet); return parseResponse(response); } private ArrayList parseResponse(HttpResponse response) { ArrayList list = null; // details omitted return list; } } public ArrayList getData(List urlList, PoolingClientConnectionManager connManager) { ArrayList jsonObjectsList = null; int numThreads = urlList.size(); ExecutorService executor = Executors.newFixedThreadPool(numThreads); List list = new ArrayList(); HttpClient httpClient = new DefaultHttpClient(connManager); for (String url : urlList) { HttpGet httpGet = new HttpGet(url); CallableThread worker = new CallableThread(httpClient, httpGet); Future submit = executor.submit(worker); list.add(submit); } for (Future future : list) { try { if (future != null) { if (jsonObjectsList == null) { jsonObjectsList = future.get(); } else { if (future.get() != null) { jsonObjectsList.addAll(future.get()); } } } } catch (InterruptedException e) { e.printStackTrace(); } catch (ExecutionException e) { e.printStackTrace(); } } executor.shutdown(); return jsonObjectsList; } }Related Questions
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