client_echo.cpp

#include <iostream>
#include <sys/socket.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sstream>
#include <unistd.h>
#include <string.h>
#include <fstream>

using namespace std;

string get_data_string(string file_name) //takes name of file as the input and returns a string that contains all the text
{
	ifstream file(file_name.c_str());
    string word;
    char x ;
    word.clear();
    int count  = 0;

    while ((x = file.get())!= EOF)
    {
        word = word + x;
    }
    file.close();
    return word;
}

void str2char(string data, char* destination){
	int size = data.size();
	char strarray[size];
	for(int i = 0;i < size;i++){
		destination[i] = (char)data[i];
	}	
}

int send(int file_descriptor,string message,int count){
	char buffer[2*count];	
	bzero(buffer,2*count);
	str2char(message,buffer);
	int n = -1;	
	n = write(file_descriptor,buffer,count);
	if(n<0){
		cout<<"Error writing to port"<<endl;
		}
	return n;
}

string recieve(int file_descriptor, int count){
	char buffer[2*count];
	bzero(buffer,2*count);
	int n = read(file_descriptor,buffer,count);
	if(n<0){
		cout<<"ERROR reading from socket"<<endl;
	}	
	string stri(buffer);
	return stri;
}

void show_available_files(int file_descriptor){
	int n = send(file_descriptor,"ls",128);
	if(n<0){
		cout<<"error asking to show files"<<endl;
	}
	string list = recieve(file_descriptor,512);
	if(list.size()<1){
		cout<<"error reading list of files"<<endl;		
	}
	else{
		cout<<list<<endl;
	}
}

void put_file(int file_descriptor, string file_name){
	string content = get_data_string(file_name);
	int n = send(file_descriptor,string("put")+" "+file_name,256);
	if(n<0){
		cout<<"error sending file..."<<endl;
	}
	n = send(file_descriptor,content,1024);
		
	if(n<0){
		cout<<"error uploading file"<<endl;
	}	
}

void get_file(int file_descriptor,string file_name){
	int n = send(file_descriptor,string("get")+" "+file_name,256);
	string content = "";
	if(n<0){
		cout<<"error requesting file"<<endl;
	}
	else{				
	  	content = recieve(file_descriptor,1024);
	  	if(content.size()<1){
	  		cout<<"error in downloading file"<<endl;
	  	}
	  	else if(content == "No such files found"){
	  		cout<<content<<endl;
	  		cout<<"try ls to check what files are present"<<endl;
	  	}
	  	else{
	  		ofstream file;
	  		file.open(file_name.c_str());
	  		file << content;
  			file.close(); 
  			cout<<"download successful"<<endl;
	  	}  		
	}
}

void show_menu(int file_descriptor){	
	int loop_invariant = 0;
	int choice = -1;	
	string file_name = "";
	while(loop_invariant == 0){
		cout<<"Enter command to"<<endl<<"1. get list of files"<<endl<<"2. download file"
		 <<endl<<"3. upload file" <<endl<<"4. get current time "<<endl<<"5. get current directory"<<endl<<"6. create new file "<<endl;
		cin>>choice;
		switch(choice){
			case 1: show_available_files(file_descriptor);
					break;
			case 2:cout<<"enter the file name to download"<<endl;
					cin>>file_name;
					get_file(file_descriptor,file_name);
					break;
			case 3:cout<<"enter the file name to upload"<<endl;
					file_name.clear();
					cin>>file_name;
					put_file(file_descriptor,file_name);
					break;
			case 4: cout<<"Current time at server is: "<<endl;
					send(file_descriptor,string("time"),256);
					cout<<recieve(file_descriptor,25);
					break;
			case 5: cout<<"Current working directory is: "<<endl;
					send(file_descriptor,string("time"),256);
					cout<<recieve(file_descriptor,25);
					break;
			case 6: cout<<"Enter file name"<<endl;
					cin>>file_name;
					send(file_descriptor,string("touch")+" "+file_name,256);
					break;
			case 9: loop_invariant = 1;
					break;
		}
	}
}

void telnet_sum(int file_descriptor){
int n = -11;
string no;
int p =0;
stringstream stream;
cout<<"Enter numbers to add"<<endl;
while(p==0){
   	cin>>n;
   	if(n<0){
   		stream << n;
		string no = stream.str();					
   		send(file_descriptor,no,256);
   		break;   						
   		}
	stream << n;
	string no = stream.str();					
   	send(file_descriptor,no,256);
   }
	cout<<"The sum is : "<<recieve(file_descriptor,256)<<endl;
}

int main(){
	int domain = AF_INET;
	int type = SOCK_STREAM;
	int protocol = 0;
	int status = 0;
	int file_descriptor = 0;
	int port_number = 5010;	
	struct sockaddr_in server_socket;
	string name = "sherlock";

	file_descriptor = socket(domain,type,protocol);
	if(file_descriptor < 0){
		cout<<"Error, failed to create sockets"<<endl;
	}
	else{		
   			bzero((char *) &server_socket, sizeof(server_socket));
   			server_socket.sin_family = AF_INET;   			
   			server_socket.sin_addr.s_addr = inet_addr("127.1.0.1");
   			server_socket.sin_port = htons(port_number);   			
   			status = connect(file_descriptor, (struct sockaddr*)&server_socket, sizeof(server_socket));
   			if(status < 0){
   				cout<<"Could not connect, please try again..."<<endl; 
   			}
   			else{
   				cout<<" ..........connected succesfully.........."<<endl;   				
   				cout<<"enter your name"<<endl;
   				cin>>name;
   				int n = send(file_descriptor,string("hello from ")+name,20);
   				if(n<0){
   					cout<<"error in client"<<endl;
   				}
   				else{
   					cout<<recieve(file_descriptor,20);
   				}

   			}
	}
}