json-configuration-loader.cpp

/**
 * JSONConfigurationLoader class implementation.
 */

#include <fstream>
#include <config-loader/json-configuration-loader.hpp>
#include <config-loader/json-field-handler.hpp>

using json = nlohmann::json;

const JsonFieldHandler &JSONConfigurationLoader::getConfigurationData() const {
    if (configurationData.has_value()) {
        return configurationData.value();
    }
    throw std::runtime_error("No JSON configuration data loaded.");
}

void JSONConfigurationLoader::loadConfigurationFromFile(const std::string &filePath) {
    // assert that the file have a .json extension
    if (!filePath.ends_with(".json")) {
        throw std::runtime_error("File is not a JSON file: " + filePath);
    }
    // get the file stream
    std::ifstream fileStream(filePath);
    // check if the file stream is open
    if (!fileStream.is_open()) {
        throw std::runtime_error("Failed to open file: " + filePath);
    }
    // check if the file is empty
    if (fileStream.peek() == std::ifstream::traits_type::eof()) {
        throw std::runtime_error("File is empty: " + filePath);
    }
    // if all checks pass, load the configuration data
    nlohmann::json jsonConfigurationData;
    try {
        fileStream >> jsonConfigurationData;
    } catch (const nlohmann::json::parse_error &e) {
        throw std::runtime_error("Failed to parse JSON file: " + filePath + "; Parse error: " + e.what());
    }
    // create the field handler object
    configurationData = JsonFieldHandler(jsonConfigurationData);
    // close the file stream
    fileStream.close();
    // print the actual configuration data;
    printf("The configuration data has been loaded from the file: %s.\n%s\n\n",
        filePath.c_str(), configurationData->getConfigurationLoaded().dump(4).c_str());
}