protohackersc/server01.c

//
// Created by PeterDwyer on 28/07/2025.
//

#include "server01.h"

#include <math.h>
#include <stdio.h>
#include <json-c/json_tokener.h>
#include <json-c/json_object.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>
#include "data.h"

#define IS_PRIME "{\"method\":\"isPrime\",\"prime\":true}\n"
#define IS_NOT_PRIME "{\"method\":\"isPrime\",\"prime\":false}\n"
#define IS_PRIME_ERROR "{\"method\":\"isPrime\",\"error\":true}\n"
int main() {
    SOCKET server = get_listen_socket();
    SOCKADDR_IN clientAddr;
    SOCKET client;
    int clientAddrSize = sizeof(clientAddr);
    int connection_number = 1;
    printf("Listening for incoming connections...\n");
    while((client = accept(server, (SOCKADDR *)&clientAddr, &clientAddrSize)) != INVALID_SOCKET)
    {
        handle_args_t *args = malloc(sizeof(handle_args_t));
        args->client = client;
        args->connection = connection_number++;
        pthread_t thread;
        pthread_create(&thread, nullptr, handle_connection, args);
    }
    return 0;
}

void *handle_connection(void *args) {
    handle_args_t *handleArgs = args;
    char buffer[1024] = {0};
    int bytesReceived;
    char_array_t *data = char_array_create(1024);
    while ((bytesReceived = recv(handleArgs->client, buffer, sizeof(buffer), 0)) > 0) {
        printf("Client sent {%d}: |%d| \n", handleArgs->connection, bytesReceived);
        char_array_append(data, buffer, bytesReceived);
        char *request;
        while ((request = char_array_get_until_char(data, '\n')) != NULL) {
            parse_request(handleArgs, request, data);
        }
        memset(buffer, 0, sizeof(buffer));
    }
    closesocket(handleArgs->client);
    free(handleArgs);
    pthread_exit(NULL);
}

void parse_request(handle_args_t *handleArgs, const char *request, char_array_t *data) {
     if (request != NULL) {
            const json_object *obj = json_tokener_parse(request);
            if (obj == NULL) {
                printf("{%d} Failed to parse json\n", handleArgs->connection);
                send(handleArgs->client, IS_PRIME_ERROR, strlen(IS_PRIME_ERROR), 0);
                char_array_destroy(data);
                closesocket(handleArgs->client);
                pthread_exit(NULL);
            }
            json_object *method_obj = json_object_object_get(obj, "method");
            json_object *number_obj = json_object_object_get(obj, "number");
            if (method_obj == NULL || number_obj == NULL) {
                printf("{%d} Missing Fields\n", handleArgs->connection);
                send(handleArgs->client, IS_PRIME_ERROR, strlen(IS_PRIME_ERROR), 0);
                char_array_destroy(data);
                closesocket(handleArgs->client);
                pthread_exit(NULL);
            }
            const int number_type = json_object_get_type(number_obj);
            if (!(json_object_is_type(method_obj, json_type_string) && (number_type== json_type_double || number_type == json_type_int))) {
                printf("{%d} Fields Wrong Type\n", handleArgs->connection);
                send(handleArgs->client, IS_PRIME_ERROR, strlen(IS_PRIME_ERROR), 0);
                char_array_destroy(data);
                closesocket(handleArgs->client);
                pthread_exit(NULL);
            }
            const char *method = json_object_get_string(method_obj);
            if (strcmp(method, "isPrime") != 0) {
                printf("{%d} Invalid method\n", handleArgs->connection);
                send(handleArgs->client, IS_PRIME_ERROR, strlen(IS_PRIME_ERROR), 0);
                char_array_destroy(data);
                closesocket(handleArgs->client);
            }
            if (number_type == json_type_double) {
                printf("{%d} Floats cannot be prime\n", handleArgs->connection);
                send(handleArgs->client, IS_NOT_PRIME, strlen(IS_NOT_PRIME), 0);
            }
            const int number = json_object_get_int(number_obj);
            bool number_is_prime;
            if (number == INT32_MAX) {
                number_is_prime = false;
            } else {
                number_is_prime = is_prime(number);
            }

            printf("{%d} '%d' is prime: %d\n", handleArgs->connection, number, number_is_prime);
            char *response = number_is_prime ? IS_PRIME : IS_NOT_PRIME;
            send(handleArgs->client, response, strlen(response), 0);
        }
}

bool is_prime(const int number) {
    if (number == 2) {
        return true;
    }
    if (number < 2 || number % 2 == 0) {
        return false;
    }

    const int limit = (int)sqrt(number);
    for (int i = 3; i <= limit; i+=2) {
        if (number % i == 0) {
            return false;
        }
    }
    return true;
}