Qt Protobuf

The Qt Protobuf generator plugin generates Qt-based classes from .proto files. You can use the classes to serialize and deserialize their associated protobuf messages.

Overview

What are protocol buffers?

Protocol buffers are a language-neutral, platform-neutral, and extensible mechanism for serializing structured data, which is compact and easy to use:

• A user defines the structure of data in .proto files.
• Proto compiler is invoked at build time on .proto files to generate code in various programming languages.

The provided format is suitable for network traffic or long-term data storage.

Which problems do protocol buffers solve?

Protocol buffers provide a serialization format for packets of typed and structured data that are up to a few megabytes in size. Moreover, it can be extended with new information without invalidating existing data or requiring code to be updated. For more information, see Protocol Buffers Overview.

What are the benefits of using Qt Protobuf?

You can use a Protocol buffers mechanism in any Qt-based project:

• No need to call a protocol buffer compiler explicitly.
• No need to integrate generated code into project tree manually.
• Convenient serialization and deserialization API.
• Integrated properties mechanism for generated protobuf messages.
• Integrated gRPC-client support (see QtGrpc module).

Incoming features

• Enabling using Qt Core and Qt GUI types as a part of *.proto schema.
• Enabling gRPC-server support.
• Enabling QML-types support for generated protobuf messages.

Using Qt Protobuf

Google protocol buffers provide a generator called protoc that supports extensions. The qtprotobufgen Tool is an extension for protoc and requires that you install protoc on your host system. For more information about the installation, see Protoc Installation.

Example of installation for Linux, using apt:

apt install -y protobuf-compiler
protoc --version  # Ensure compiler version is 3+

For more information about component API usage, see CMake API.

CMake API

• CMake Commands in Qt6 Protobuf

Class Documentation

C++ Classes

Examples

• Qt Protobuf Examples