httpClient-WebPage

#include"stdio.h"    
   #include"stdlib.h"    
   #include"sys/types.h"    
   #include"sys/socket.h"    
   #include"string.h"    
   #include"netinet/in.h"    
   #include"netdb.h"  
      
   #define BUF_SIZE 1024   
      
  int get_request(char * url, char * port);  
  int isValidIP(char * ip);  
  int parseHeader(char * header);  
  char * splitKeyValue(char * line, int index);  
  void openFile();  
    
  FILE * fileptr;  
  char keys[][25] = {"Date: ", "Hostname: ", "Location: ", "Content-Type: "};  
  char status[4] = {0, 0, 0, 0};  
  char contentFileType[100];  
  char path[1000];  
    
  int main(int argc, char**argv) {    
   struct sockaddr_in addr, cl_addr;    
   int sockfd, ret;   
   struct hostent * server;  
   char * url, * temp;  
   int portNumber;  
   char * fileName;  
   char status_ok[] = "OK";  
   char buffer[BUF_SIZE];   
   char http_not_found[] = "HTTP/1.0 404 Not Found";  
   char http_ok[] = "HTTP/1.0 200 OK";  
   char location[] = "Location: ";  
   char contentType[] = "Content-Type: ";  
   int sPos, ePos;  
    
   if (argc < 3) {  
    printf("usage: [URL] [port number]\n");  
    exit(1);    
   }  
    
   url = argv[1];  
   portNumber = atoi(argv[2]);  
    
   if ((temp = strstr(url, "http://")) != NULL) {  
    url = url + 7;  
   } else if ((temp = strstr(url, "https://")) != NULL) {  
    url = url + 8;  
   }  
    
   if (portNumber > 65536 || portNumber < 0) {  
    printf("Invalid Port Number!");  
    exit(1);  
   }  
     
   sockfd = get_request(url, argv[2]);   
    
   memset(&buffer, 0, sizeof(buffer));  
   ret = recv(sockfd, buffer, BUF_SIZE, 0);    
   if (ret < 0) {    
    printf("Error receiving HTTP status!\n");      
   } else {  
    printf("%s\n", buffer);  
    if ((temp = strstr(buffer, http_ok)) != NULL) {  
     send(sockfd, status_ok, strlen(status_ok), 0);  
    } else {  
     close(sockfd);  
     return 0;  
    }  
   }  
    
   memset(&buffer, 0, sizeof(buffer));   
   ret = recv(sockfd, buffer, BUF_SIZE, 0);    
   if (ret < 0) {    
    printf("Error receiving HTTP header!\n");      
   } else {  
    printf("%s\n", buffer);  
    if (parseHeader(buffer) == 0) {  
     send(sockfd, status_ok, strlen(status_ok), 0);  
    } else {  
     printf("Error in HTTP header!\n");  
     close(sockfd);  
     return 0;  
    }  
   }   
    
   fileptr = fopen(path, "w");  
   if (fileptr == NULL) {  
    printf("Error opening file!\n");  
    close(sockfd);  
    return 0;  
   }  
    
   memset(&buffer, 0, sizeof(buffer));  
   while (recv(sockfd, buffer, BUF_SIZE, 0) > 0) { //receives the file  
    if ((strstr(contentFileType, "text/html")) != NULL) {  
     fprintf(fileptr, "%s", buffer);  
    } else {  
     fwrite(&buffer, sizeof(buffer), 1, fileptr);  
    }  
    memset(&buffer, 0, sizeof(buffer));  
   }  
    
   fclose(fileptr);  
   close(sockfd);  
    
   openFile();  
    
   return 0;  
  }  
    
    
  int get_request(char * url, char * port) {  
    
   int sockfd, bindfd;  
          char * ptr, * host;  
   char getrequest[1024];  
          struct sockaddr_in addr;  
    
   if (isValidIP(url)) { //when an IP address is given  
    sprintf(getrequest, "GET / HTTP/1.0\nHOST: %s\n\n", url);  
          } else { //when a host name is given  
    if ((ptr = strstr(url, "/")) == NULL) {  
     sprintf(getrequest, "GET / HTTP/1.0\nHOST: %s\n\n", url);  
    } else {  

     strcpy(path, ptr);  
            host = strtok(url, "/");  
     sprintf(getrequest, "GET %s HTTP/1.0\nHOST: %s\n\n", path, url);  
    }  
   }   
    
   // creates a socket to the host  
   sockfd = socket(AF_INET, SOCK_STREAM, 0);  
   if (sockfd < 0) {    
    printf("Error creating socket!\n");    
    exit(1);    
   }    
   printf("Socket created...\n");  
    
   memset(&addr, 0, sizeof(addr));    
   addr.sin_family = AF_INET;    
   addr.sin_addr.s_addr = inet_addr(url);  
   addr.sin_port = htons(atoi(port));  
    
   if (connect(sockfd, (struct sockaddr *) &addr, sizeof(addr)) < 0 ) {  
    printf("Connection Error!\n");  
    exit(1);  
   }  
   printf("Connection successful...\n\n\n");  
   ptr = strtok(path, "/");  
   strcpy(path, ptr);  
   write(sockfd, getrequest, strlen(getrequest));  
    
   return sockfd;  
  }  
    
    
  int isValidIP(char * ip) {  
   struct sockaddr_in addr;  
   int valid = inet_pton(AF_INET, ip, &(addr.sin_addr));  
   return valid != 0;  
  }  
    
    
  int parseHeader(char * header) {  
   char * line, * key, * value;  
   char temp[100];  
   int i = 0;  
   line = strtok(header, "\n");  
   while (line != NULL) {  
    strcpy(temp, line);  
    value = splitKeyValue(line, i);    
    if (i == 3) {     
     strcpy(contentFileType, value);  
    }  
    line = strtok(NULL, "\n");  
    i++;   
   }  
   for (i = 0; i < 4; i++) {  
    if (status[i] == 0) return 1;  
   }  
   return 0;  
  }  
    
  char * splitKeyValue(char * line, int index) {  
   char * temp;  
   if ((temp = strstr(line, keys[index])) != NULL) {  
    temp = temp + strlen(keys[index]);  
    status[index] = 1;  
   }  
   return temp;  
  }  
    
  void openFile() {  
   char * temp;  
   char command[100];  
   char fileName[1000];  
   strcpy(fileName, path);  
   if ((temp = strstr(contentFileType, "text/html")) != NULL) {  
    if ((temp = strstr(fileName, ".txt")) != NULL) {  
     sprintf(command, "gedit %s", fileName);  
    } else {  
     sprintf(command, "firefox %s", fileName);  
    }  
    system(command);  
   } else if ((temp = strstr(contentFileType, "application/pdf")) != NULL) {  
    sprintf(command, "acroread %s", fileName);  
    system(command);  
   } else {  
    printf("The filetype %s is not supported. Failed to open %s!\n", contentFileType, fileName);  
   }  
  }