dreamplayerzhang/cppconfigframework

C++ Config Framework

C++ Config Framework

The purpose of this config framework is to simplify creation and loading of config files for C++ applications.

The framework can be used to create cross-platform applications, since it is using only Qt and STL libraries.

Requirements

Requirements document can be found here.

Design

Design document can be found here.

Build and deployment

For building the following requirements are needed:

• CMake v3.5 or later
• C++14 compliant compiler
• Qt v5.9 or later (only Core and Test modules)
• Cedar Framework

If the library needs to be deployed to a custom location you need to set the CMAKE_INSTALL_PREFIX variable or if you need to use a custom Qt installation and/or CedarFramework is not deployed to one of the standard locations you need to set the CMAKE_PREFIX_PATH variable.

Example:

$ cmake -DCMAKE_INSTALL_PREFIX=path/to/install/dir -DCMAKE_PREFIX_PATH="path/to/qt/dir;path/to/CedarFramework/dir" path/to/source/dir

Then build and deploy the library:

$ cmake --build . --target install

Usage

CMake Integration

To use this module in a CMake project you need to have a built and deployed CedarFramework dependency. Then build and deploy CppConfigFramework and add this to your project's CMakeLists.txt:

find_package(CppConfigFramework REQUIRED)

And link it to your target:

target_link_libraries(target_name PUBLIC CppConfigFramework::CppConfigFramework)

Creating a configuration class

Here is an example of a configuration class that has three parameters with one of them being a sub-configuration class:

#include <CppConfigFramework/ConfigLoader.hpp>

class ExampleSubConfig : public CppConfigFramework::ConfigLoader
{
public:
    ~ExampleSubConfig() override = default;

    QString name;

private:
    bool loadConfigParameters(
        const CppConfigFramework::ConfigObjectNode &config) override
    {
        return loadRequiredConfigParameter(&name, "name", config);
    }
};

class ExampleConfig : public CppConfigFramework::ConfigLoader
{
public:
    ~ExampleConfig() override = default;

    QString type;
    int count;
    ExampleSubConfig sub;

private:
    bool loadConfigParameters(
        const CppConfigFramework::ConfigObjectNode &config) override
    {
        if (!loadRequiredConfigParameter(&type, "type", config))
        {
            return false;
        }

        count = 0;
        if (!loadOptionalConfigParameter(&count, "count", config))
        {
            return false;
        }

        return sub.loadConfig("sub", config);
    }
};

Loading a configuration file

To load the configuration you need to do something like this:

#include <CppConfigFramework/ConfigReader.hpp>
#include <CppConfigFramework/ConfigNodePath.hpp>

int main()
{
    using namespace CppConfigFramework;
    
    ConfigReader configReader;
    EnvironmentVariables environmentVariables;

    auto config = configReader.read("path/to/config/file",
                                    QDir("path/to/config/dir"),
                                    ConfigNodePath::ROOT_PATH,
                                    ConfigNodePath::ROOT_PATH,
                                    {},
                                    &environmentVariables);

    ExampleConfig exampleConfig;
    exampleConfig.loadConfig(*config);
}

For this example the following configuration file will be used:

{
    "config":
    {
        "type": "test",
        "sub":
        {
            "name": "name"
        }
    }
}

Which will produce the following values:

Parameter	Value
exampleConfig.type	"test"
exampleConfig.count	0 (default value)
exampleConfig.sub.name	"name"