hello-world-cpp/task_5/routes.cpp

#include "routes.h"

std::string RouteHandler::get_string_from_regex(std::string text, std::regex pattern) {
    auto parts_begin = std::sregex_iterator(
        text.begin(),
        text.end(),
        pattern
    );
    auto parts_end = std::sregex_iterator();
    if (std::distance(parts_begin, parts_end)) {
        std::smatch part_match = *parts_begin;
        return part_match.str();
    }
    return "";
}

struct request_info RouteHandler::parse_request(const std::string& request) {
    struct request_info this_request;

    std::regex request_line_regex(
        "(GET|POST|PUT|DELETE|HEAD|TRACE|OPTIONS|CONNECT) .* HTTP/"
    );
    std::regex method_regex("^[A-Z]+");
    std::regex path_regex("/[^? ]*");
    std::regex params_regex(R"(\?[^ ]*)");


    std::string request_line = get_string_from_regex(request, request_line_regex);
    this_request.method = get_string_from_regex(request_line, method_regex);
    this_request.path = get_string_from_regex(request_line, path_regex);
    this_request.params = get_string_from_regex(request_line, params_regex);

    return this_request;
}




std::string RouteHandler::get_response_by_request(const std::string& request) {
    struct request_info this_request = parse_request(request);
    if (this_request.method == "GET") {
        if (this_request.path == "/current") {
            return get_current_temperature(this_request);
        }
        if (this_request.path == "/get") {
            return get_temperature_by_period(this_request);
        }
    }

    return format_http_response("404 NOT FOUND", "404 Not Found");
}



std::string RouteHandler::get_current_temperature(struct request_info this_request) {
    std::string temperature_info = (
        "{\"temperature\": \"22°C\", \"weather\": \"good\"}"
    );
    return format_http_response("200 OK", temperature_info);
}

std::string RouteHandler::get_temperature_by_period(struct request_info this_request) {
    std::map<std::string, std::string> params_data;
    std::string temp = "", temp_key = "", temp_value = "";
    bool key_is_ready = 0;

    for (char sym : this_request.params) {
        if (sym == '?') {
            continue;
        }
        if (sym == '&') {
            if (temp_value.length()) {
                params_data[temp_key] = temp_value;
            }
            temp = "";
            temp_key = "";
            temp_value = "";
            key_is_ready = 0;
            continue;
        }
        if (sym == '=') {
            key_is_ready = 1;
            continue;
        }
        if (!key_is_ready) {
            temp_key += sym;
        }
        else {
            temp_value += sym;
        }
    }

    if (temp_value.length()) {
        params_data[temp_key] = temp_value;
    }


    std::string response_json = "{";

    for (auto item : params_data) {
        response_json += ("\"" + item.first + "\": \"" + item.second + "\",");

    }

    response_json.pop_back();
    response_json += "}";
    return format_http_response("200 OK", response_json);
}


std::string RouteHandler::format_http_response(std::string status, std::string text) {
    return (
            "HTTP/1.1 " + status + "\r\n"
            "Content-Type: application/json\r\n"
            "Content-Length: " + std::to_string(text.length()) + "\r\n"
            "\r\n"
            + text
        );
}