Working with Json configuration files

The purpose of Nickvision::Helpers::JsonFileBase is to act as a base when defining your own json data objects that you would like to be saved and retrieved from disk.

Here are some key points when defining your own configuration objects:

• Your data object's constructor must take const std::filesystem::path& path parameter and pass it to JsonFileBase's constructor.
• JsonFileBase exposes protected templated T get(const std::string& key, const T& defaultValue) and void set(const std::string& key, const T& value) methods which you must use in your implementation to get and store data from the json object.
• You must explicitly call the save method on your object when you want to save the configuration json file to disk. Calling get and set are not enough to trigger saving the file on disk.

Here is an example of a custom configuration object using JsonFileBase:

using namespace Nickvision::Events;
using namespace Nickvision::Helpers;
 
class AppConfig : public JsonFileBase
{
public:
    AppConfig(const std::filesystem::path& path)
        : JsonFileBase{ path } 
    { 
 
    }
 
    bool getAutomaticallyCheckForUpdates() const
    {
        return get("AutomaticallyCheckForUpdates", true);
    }
 
    void setAutomaticallyCheckForUpdates(bool value)
    {
        set("AutomaticallyCheckForUpdates", value);
    }
};
 
int main()
{
    AppConfig config{ "config.json" };
    config.saved() += [](const EventArgs& e) { std::cout << "Config saved to disk." << std::endl; };
    if(config.getAutomaticallyCheckForUpdates())
    {
        std::cout << "Checking for updates..." << std::endl;
    }
    config.setAutomaticallyCheckForUpdates(false);
    config.save(); //above lambda will be invoked
    return 0;
}