# Writing Plugins

  • Qv2ray Plugin Documentations

# What is a plugin

A plugin is, technically, a shared library that implements a specific interface, Qv2rayPlugin::QvPluginInterface in this case. So that can be loaded by Qv2ray.

# Prerequisites when writing a plugin

# Compiler Version / Options

  • For Linux and macOS, there’s no compiler limitations.
  • MSVC is required when compiling a plugin.
  • -fno-sized-deallocation Should be used when compiling the plugin, especially when “Building plugins using Github Action

# Qt Version Limitations

  • It’s a Qt limit that the version which a plugin was built against should not be greater than that of the loader application (Qv2ray in this case)
  • We suggest building plugins using Qt 5.11.3 since it’s the oldest version Qv2ray supports.
  • These dependencies should be statically linked into the plugin library, otherwise:
    • Tell the users to download/install all dependencies’ library from wherever they can.
  • Exception: OpenSSL SHOULD NOT be statically linked.
    • Qv2ray has its own OpenSSL dependency check and will make sure a compatible OpenSSL has been installed.

# Creating a plugin

You have 2 choices when initiating a plugin.

  1. Creating plugin using provided Template project:

    There’s a repository called QvPlugin-Template (opens new window), which can be used to create your own plugin.

  2. Creating plugin from from scratch.

# 1. Using the template project

  1. Click the “Use This Plugin” in the Github Repository page and follow the instructions.

  2. Clone your repository just created.

  3. Execute the command, since Github didn’t persist submodule data within the template repo.

    git submodule add --force https://github.com/Qv2ray/QvPlugin-Interface/ ./interface
    
  4. Select your Build Generator, by doing: Remove unwanted project files e.g. QvSimplePlugin.pro or CMakeLists.txt Remove unwanted CI configurations by removing it from ./.github/workflows/

  5. Open the .pro file or CMakeLists.txt in QtCreator.

  6. Do any modifications especially plugin metadata in the QvSimplePlugin.hpp

  7. Test build locally, then push to the Github to see if the Github Action can pass.

# 2. Creating a plugin from scratch

  1. Create a git repoaitory

  2. Add plugin interface in https://github.com/Qv2ray/QvPlugin-Interface/ as a submodule

  3. Include QvPluginInterface.cmake or QvPluginInterface.pri into your project file.

  4. Write a class, which inherits Qv2rayPlugin::Qv2rayInterface and implement every virtual functions.

  5. Add slot declaration of those functions:

    void PluginLog(const QString &) const;
    void PluginErrorMessageBox(const QString &);
    
  6. You may return a nullptr in GetPluginKernel function if your plugin does not have SPECIAL_TYPE_KERNEL in the metadata. The same as GetSerializer, but do not return nullptr in the GetEventHandler().