client.cpp

//standard import
#include <iostream>
#include <stdlib.h>
#include <string.h>
using namespace std;

//import for to grab socket / ip includes necessaryq
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <arpa/inet.h>

#include <vector>

/*
This program is fully developed and created by: Marcus Ruth 
https://www.github.com/polter-dev/miniredis_cpp

Program Synopsis: client that connects and communicates to the server to simulate a redis like system
*/


//grab socket and error handles
int grabSocket(){
    int fd = socket(PF_INET, SOCK_STREAM, 0);
        if (fd == -1){
            printf("Socket could not be grabbed!\n");
            exit(errno);
        }
    return fd;
}

void initSockAddr(struct sockaddr_in *s1){
    s1->sin_family = AF_INET;
    s1->sin_port = htons(1234);
    s1->sin_addr.s_addr = inet_addr("127.0.0.1"); //local address
}

void connectSock(int fd, struct sockaddr_in *s){
    int connectNo = connect(fd, (struct sockaddr *)s, sizeof(*s));
    if (connectNo){
        printf("Connect could not be made\n");
        exit(errno);
    }
}

int sendText(const char *word, int fd){
    int val = send(fd, word, strlen(word), 0);
    if (val == -1){
        printf("There was an issue sending!\n");
        exit(errno);
    }
    return val;
}

char *setWord(char input[1024]){
    int len = strlen(input);
    char *ret = (char*)malloc(sizeof(char) * (len+1));
    strcpy(ret, input);
    return ret;
}

string buildRESPEncoding(std::vector<string> &arr, int count){

    string start = "*" + std::to_string(count) + "\r\n";
    
    for (int i = 0; i < count; i++){
        string temp = "$" + std::to_string(arr[i].length()) + "\r\n" + arr[i] + "\r\n";
        start = start.append(temp);
    }
    
    return start;
}

int encodeSendCmd(int fd, char *word){
    if (!word) return 0;

    std::vector<string> totalWords;
    
    int count = 0;
    char *poach = strtok(word, " ");

    while (poach){
        totalWords.push_back(poach);
        count++;
        poach = strtok(NULL, " ");
    }

    string build = buildRESPEncoding(totalWords, count);

    return sendText(build.c_str(), fd);
}   

void extractSimpleString(char *response){
    char *finder = strchr(response, '\r');
    string word(response + 1, finder);
    cout << word << endl;
}

void extractBulkString(char *response){
    char *finder = strchr(response, '\r');
    string num(response + 1, finder);
    int size = stoi(num);
    std::string word(finder + 2, size);

    cout << word << endl;
}

void decodeResponse(char* response){
    char type = response[0];

    if (type == '+'){
        extractSimpleString(response);
    } else if (type == '$'){
        extractBulkString(response);
    } else if (type == '_'){
        cout << "(nil)" << endl;
    } else if (type == '-'){
        extractSimpleString(response);
    }
}

int clientRun(int fd){
    char userBuffer[1024];
    fgets(userBuffer, 1024, stdin);

    userBuffer[strcspn(userBuffer, "\n")] = '\0';

    char *temp = setWord(userBuffer);
    int sent = encodeSendCmd(fd, temp);
    if (!strncmp(temp, "QUIT", 4)){
        free(temp);
        return 0;
    }
    free(temp);

    char *buffer = (char*)malloc(sizeof(char) * 1024 + 1);
    int received = recv(fd, buffer, 1024, 0);
    if (received == -1){
        printf("Issue receiving size of text in bytes\n");
        exit(-1);
    } else if (received == 0){
        printf("TCP connection was closed on server side before processing \n");
        exit(0);
    }
    

    decodeResponse(buffer);
    free(buffer);

    return 1;
}

int main(){
    int fd = grabSocket();

    struct sockaddr_in clientSock1;
    initSockAddr(&clientSock1);

    connectSock(fd, &clientSock1);

    int x = 1;
    cout << "Input commands\n" << endl;

    while(x){
        x = clientRun(fd);
    }
    
    close(fd);
    return 0;
}