Multithreaded-Web-server-proxy/proxy_server_with_cache.c at main · Quartz1605/Multithreaded-Web-server-proxy · GitHub

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#include "proxy_parse.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <sys/wait.h>
#include <errno.h>
#include <pthread.h>
#include <semaphore.h>
#include <time.h>

#define MAX_CLIENTS 10
#define MAX_BYTES 4096
#define MAX_ELEMENT_SIZE 10*(1<<10)
#define MAX_SIZE 200*(1<<20) // Cache size = 200*2^20

typedef struct cache_element
{

  char *data;
  int len;               // for bytes info..
  char *url;             // konsi url pe request maari hai
  time_t lru_time_track; // lru implementation ke liye use karre
  struct cache_element *next;

} cache_element;

cache_element *find(char *url);

int add_cache_element(char *data, int size, char *url);

void remove_cache_element();

int port_number = 8080;

int proxy_socketId;

int connectRemoteServer(char *host_addr, int port_num)
{

  int remoteSocket = socket(AF_INET, SOCK_STREAM, 0);

  if (remoteSocket < 0)
  {
    printf("creating socket failed");
    return -1;
  }

  struct hostnet *host = gethostbyname(host_addr); // Ye use hora to convert host name to IP address

  struct sockaddr_in server_addr;
  bzero((char *)&server_addr, sizeof(server_addr));
  server_addr.sin_family = AF_INET;
  server_addr.sin_port = htons(port_num);

  bcopy((char *)&host->h_addr, (char *)&server_addr.sin_addr.s_addr, host->h_length);
  // Copying the host ka IP address from host to server_addr.sin_addr.s_addr, host->h_length to get idea of how many bytes to copy...

  if (connect(remoteSocket, (struct sockaddr *)&server_addr, (size_t)sizeof(server_addr)) < 0)
  {
    perror("Error in connecting\n");
    return -1;
  }

  return remoteSocket;
}

int checkHTTPVersion(char *msg)
{

  int version = -1;

  if (strncmp(msg, "HTTP/1.1", 8) == 0)
  {

    version = 1;
  }
  else if (strncmp(msg, "HTTP/1.0", 8) == 0)
  {
    version = 1;
  }
  else
    version = -1;

  return version;
}

//ye gpt kiya hai maine..
int sendErrorMessage(int socket, int status_code)
{
  char str[1024];
  char currentTime[50];
  time_t now = time(0);

  struct tm data = *gmtime(&now);
  strftime(currentTime, sizeof(currentTime), "%a, %d %b %Y %H:%M:%S %Z", &data);

  switch (status_code)
  {
  case 400:
    snprintf(str, sizeof(str), "HTTP/1.1 400 Bad Request\r\nContent-Length: 95\r\nConnection: keep-alive\r\nContent-Type: text/html\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>400 Bad Request</TITLE></HEAD>\n<BODY><H1>400 Bad Rqeuest</H1>\n</BODY></HTML>", currentTime);
    printf("400 Bad Request\n");
    send(socket, str, strlen(str), 0);
    break;

  case 403:
    snprintf(str, sizeof(str), "HTTP/1.1 403 Forbidden\r\nContent-Length: 112\r\nContent-Type: text/html\r\nConnection: keep-alive\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>403 Forbidden</TITLE></HEAD>\n<BODY><H1>403 Forbidden</H1><br>Permission Denied\n</BODY></HTML>", currentTime);
    printf("403 Forbidden\n");
    send(socket, str, strlen(str), 0);
    break;

  case 404:
    snprintf(str, sizeof(str), "HTTP/1.1 404 Not Found\r\nContent-Length: 91\r\nContent-Type: text/html\r\nConnection: keep-alive\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>404 Not Found</TITLE></HEAD>\n<BODY><H1>404 Not Found</H1>\n</BODY></HTML>", currentTime);
    printf("404 Not Found\n");
    send(socket, str, strlen(str), 0);
    break;

  case 500:
    snprintf(str, sizeof(str), "HTTP/1.1 500 Internal Server Error\r\nContent-Length: 115\r\nConnection: keep-alive\r\nContent-Type: text/html\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>500 Internal Server Error</TITLE></HEAD>\n<BODY><H1>500 Internal Server Error</H1>\n</BODY></HTML>", currentTime);
    // printf("500 Internal Server Error\n");
    send(socket, str, strlen(str), 0);
    break;

  case 501:
    snprintf(str, sizeof(str), "HTTP/1.1 501 Not Implemented\r\nContent-Length: 103\r\nConnection: keep-alive\r\nContent-Type: text/html\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>404 Not Implemented</TITLE></HEAD>\n<BODY><H1>501 Not Implemented</H1>\n</BODY></HTML>", currentTime);
    printf("501 Not Implemented\n");
    send(socket, str, strlen(str), 0);
    break;

  case 505:
    snprintf(str, sizeof(str), "HTTP/1.1 505 HTTP Version Not Supported\r\nContent-Length: 125\r\nConnection: keep-alive\r\nContent-Type: text/html\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>505 HTTP Version Not Supported</TITLE></HEAD>\n<BODY><H1>505 HTTP Version Not Supported</H1>\n</BODY></HTML>", currentTime);
    printf("505 HTTP Version Not Supported\n");
    send(socket, str, strlen(str), 0);
    break;

  default:
    return -1;
  }
  return 1;
}

int handle_request(int clientSocketId, ParsedRequest *request, char *tempReq)
{

  char *buff = (char *)malloc(sizeof(char) * MAX_BYTES);

  strcpy(buff, "GET");
  strcat(buff, request->path);
  strcat(buff, " ");
  strcat(buff, request->version);
  strcat(buff, "\r\n");

  int len = strlen(buff);

  if (ParsedHeader_set(request, "Connection", "close") < 0)
  {
    printf("set header key is not working");
  }

  if (ParsedHeader_get(request, "Host") == NULL)
  {

    if (ParsedHeader_set(request, "Host", request->host) < 0)
    {
      printf("Set Host header key is not working");
    }
  }

  if (ParsedRequest_unparse_headers(request, buff + len, (size_t)(MAX_BYTES - len)) < 0)
  {

    printf("unparse failed");

  } // Isse basically buffer mein request ka host and connection add hora hai

  /* final buffer kuch aisa dikhta hai
  GET / HTTP/1.1\r\n
  Host: google.com\r\n
  Connection: close\r\n
  \r\n
  */

  int server_port = 80;

  if (request->port != NULL)
  {
    server_port = atoi(request->port);
  }

  int remoteSocketId = connectRemoteServer(request->host, server_port);

  if (remoteSocketId < 0)
  {
    return -1;
  }

  int bytes_send = send(remoteSocketId, buff, strlen(buff), 0);
  bzero(buff, MAX_BYTES);

  bytes_send = recv(remoteSocketId, buff, MAX_BYTES - 1, 0);
  // recv returns byte count..

  char *temp_buffer = (char *)malloc(sizeof(char) * MAX_BYTES);

  int temp_buffer_size = MAX_BYTES;
  int temp_buffer_index = 0;

  while (bytes_send > 0)
  {

    bytes_send = send(clientSocketId, buff, bytes_send, 0);
    for (int i = 0; i < (bytes_send / sizeof(char)); i++)
    {

      temp_buffer[temp_buffer_index] = buff[i];
      temp_buffer_index++;
    }

    temp_buffer_size += MAX_BYTES;
    temp_buffer = (char *)realloc(temp_buffer, temp_buffer_size)

        if (bytes_send < 0)
    {
      perror("Error in sending data to the client");
      break;
    }

    bzero(buff, MAX_BYTES);
    bytes_send = recv(remoteSocketId, buff, MAX_BYTES - 1, 0);
  }

  temp_buffer[temp_buffer_index] = '\0';
  free(buff);
  add_cache_element(temp_buffer, strlen(temp_buffer), tempReq);
  free(temp_buffer);
  close(remoteSocketId);
  return 0;
}

pthread_t tid[MAX_CLIENTS]; // array of thread ids hai..

sem_t semaphore;
pthread_mutex_t lock;

cache_element *head;

int cache_size;

void *thread_fn(void *socketNew)
{
  sem_wait(&semaphore);

  int p;
  sem_getvalue(&semaphore, p);

  printf("semaphore value is %d\n", p);

  int *t = (int *)socketNew;

  int socket = *t;

  int bytes_send_clients, len;

  char *buffer = (char *)calloc(MAX_BYTES, sizeof(char));
  bzero(buffer, MAX_BYTES);

  bytes_send_clients = recv(socket, buffer, MAX_BYTES, 0);

  while (bytes_send_clients > 0)
  {
    len = strlen(buffer);
    if (strstr(buffer, "\r\n\r\n") == NULL)
    {
      bytes_send_client = recv(socket, buffer + len, MAX_BYTES - len, 0);
    }
    else
    {
      break;
    }
  }

  // creating a clone req cus baadme lag sakte while storing in cache..
  char *tempReq = (char *)malloc(strlen(buffer) * sizeof(char) + 1);

  for (int i = 0; i < strlen(buffer); i++)
  {

    tempReq[i] = buffer[i];
  }

  cache_element *temp = find(tempReq);

  if (temp != NULL)
  {
    int size = (temp->len) / sizeof(char);
    int pos = 0;

    char response[MAX_BYTES];

    while (pos < size)
    {
      bzero(response, MAX_BYTES);
      for (int i = 0; i < MAX_BYTES; i++)
      {
        response[i] = temp->data[i];
        pos++;
      }
      send(socket, response, MAX_BYTES, 0);
    }

    printf("Data retrieved from cache\n");
    printf("%s\n\n", response);
  }
  else if (bytes_send_client > 0)
  {
    len = strlen(buffer);
    ParsedRequest *request = ParsedRequest_create();

    if (ParsedRequest_parse(request, buffer, len) < 0)
    {
      printf("Parsing failed\n");
    }
    else
    {
      bzero(buffer, MAX_BYTES);

      if (!strcmp(request->method, "GET"))
      {
        if (request->host && request->path && checkHTTPversion(request->version) == 1)
        {
          bytes_send_client = handle_request(socket, request, tempReq);

          if (bytes_send_client == -1)
          {
            sendErrorMessage(socket, 500);
          }
        }
        else
        {
          sendErrorMessage(socket, 500);
        }
      }
      else
      {
        printf("This server proxy doesn't support any method other than 'GET'");
      }
    }

    ParsedRequest_destroy(request);
  }
  else if (bytes_send_client == 0)
  {
    printf("Client is disconnected");
  }

  shutdown(socket, SHUT_RDWR);
  close(socket);
  free(buffer);
  sem_post(&semaphore); // Ye +1 karega
  sem_getvalue(&semaphore, p);

  printf("Semaphore post value is %d", p);
  free(tempReq);
}

int main(int argc, char *argv[])
{

  int client_socketId, client_len;

  struct sockaddr_in server_addr, client_addr;

  sem_init(&semaphore, 0, MAX_CLIENTS);

  pthread_mutex_init(&lock, NULL);

  if (argv == 2)
  {
    port_number = atoi(argv[1]);
  }
  else
  {
    printf("Too few arguments\n");
    exit(1);
  }

  printf("Starting Proxy server at port : %d\n", port_number);

  proxy_socketId = socket(AF_INET, SOCK_STREAM, 0);

  if (proxy_socketId < 0)
  {
    perror("Failed to create a socket\n");
    exit(1);
  }

  int reuse = 1;

  if (setsockopt(proxy_socketId, SOL, SO_REUSEADDR, (char *)&reuse, sizeof(reuse)) < 0)
  {
    perror("setSockOpt failed\n");
  }

  bzero((char *)&server_addr, sizeof(server_addr));

  server_addr.sin_family = AF_INET;
  server_addr.sin_port = htons(port_number);
  server_addr.sin_addr.s_addr = INADDR_ANY;

  if (bind(proxy_socketId, (struct socketaddr *)&server_addr, sizeof(server_addr)) < 0)
  {
    perror("Port is not available\n");
    exit(1);
  }
  printf("Binding on port %d\n", port_number);

  int listen_status = listen(proxy_socketId, MAX_CLIENTS);

  if (listen_status < 0)
  {
    perror("Error in listening \n");
    exit(1);
  }

  int i = 0;
  int Connected_socketId[MAX_CLIENTS];

  while (1)
  {
    bzero((char *)&client_addr, sizeof(client_addr));
    client_len = sizeof(client_addr);

    client_socketId = accept(proxy_socketId, (struct sockaddr *)&client_addr, (socklen_t *)&client_len);

    if (client_socketId < 0)
    {
      printf("Not able to connect");
      exit(1);
    }
    else
    {
      Connected_socketId[i] = client_socketId;
    }

    struct sockaddr_in *client_pt = (struct sockaddr_in *)&client_addr;

    struct in_addr ip_addr = client_pt->sin_addr;
    char str[INET_ADDRSTRLEN];
    inet_ntop(AF_INET, &ip_addr, str, INET_ADDRSTRLEN);
    printf("Client is connected with port number %d and ip address is %s\n", ntohs(client_addr.sin_port), str) // this piece of code is just for printing the portnumber and ip_addr so chalta hai if you don't get it...

        pthread_create(&tid[i], NULL, thread_fn, (void *)&Connected_socketId[i]);

    i++;
  }

  close(proxy_socketId);
  return 0;
}


//Cache ke codes ka implementation...


cache_element* find(char* url){

  cache_element* site = NULL;

  int temp_lock_val = pthread_mutex_lock(&lock);

  printf("Remove cache, Lock acquried %d\n",temp_lock_val);

  if(head != NULL){

    site = head;

    while(site != NULL){

      if(!strcmp(site->url,url)){
        printf("LRU time track before: %ld",site->lru_time_track);
        printf("\n url found \n");
        site->lru_time_track = time(NULL);
        printf("LRU time track after %ld",site->lru_time_track);
        break;
      }

      site = site->next;
    }
  }else{
    printf("url not found");
  }

  temp_lock_val = pthread_mutex_unlock(&lock);
  printf("Lock is unlocked");


}

void remove_cache_element(){

  cache_element *p;
  cache_element *q;

  cache_element *temp;

  int temp_lock_val = pthread_mutex_lock(&lock);
  printf("Lock is acquired");

  //Least value of timestamp means oldest element used..

  if(head != NULL){
    for(q = head,p = head,temp = head;q->next != NULL;q = q->next){

      if(((q->next)->lru_time_track) < (temp->lru_time_track)){
        temp = q->next;
        p = q;
      }


    }

    if(temp == head){
      head = head->next;
    }else{
      p->next = temp->next;
    }

    cache_size = cache_size-(temp->len)-sizeof(cache_element)-strlen(temp->url)-1;

    free(temp->data);
    free(temp->url);
    free(temp);

  }

  temp_lock_val = pthread_mutex_unlock(&lock);
  printf("Remove cache lock\n");

}

int add_cache_element(char* data,int size,char* url){
  int temp_lock_val = pthread_mutex_lock(&lock);

  printf("Cache lock acquired");

  int element_size = size+1+strlen(url)+sizeof(cache_element);

  //If element_size jyada hogayi than cache_size..
  if(element_size>MAX_ELEMENT_SIZE){
    temp_lock_val = pthread_mutex_unlock(&lock);
    printf("Add cache lock is unlocked\n");
    return 0;
  }else{

    while(cache_size+element_size > MAX_SIZE){
      remove_cache_element();
    }
    cache_element* element = (cache_element*)malloc(sizeof(cache_element));

    element->data = (char*)malloc(size+1);
    strcpy(element->data,data);
    element->url = (char*)malloc(1+strlen(url)*sizeof(char));
    strcpy(element->url,url);

    element->lru_time_track = time(NULL);
    element->next = head;

    element->len = size;
    head = element;

    cache_size += element_size;

    temp_lock_val = pthread_mutex_unlock(&lock);
    printf("Removed the mutex locks");

  }


}