Qt Protobuf

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

概述

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 文件。
• 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 Qt GRPC module ).
• Integrated QML-types support for generated protobuf messages. See Qt Protobuf QML Types
• Enabled using Qt Core and Qt GUI types as a part of *.proto schema. See Protobuf Qt Core Types Module and Protobuf Qt GUI types module .

Incoming features

• Enabling gRPC-server support.

使用模块

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+
  							

• Example of installation for Windows using vcpkg

QML API

The QML types of the module are available through the QML and QML_URI options in the qt_add_protobuf macro. The import name is equal to the .proto package name or defined by QML_URI option in the qt_add_protobuf macro. To use the types, add the following import statement to your .qml file:

import my.proto.package.uri
					

C++ API

使用 Qt 模块的 C++ API 要求直接 (或透过其它依赖) 链接到模块库。几个构建工具对此有专用支持，包括 CMake and qmake .

构建采用 CMake

使用 find_package() 命令定位所需模块组件在 Qt6 包：

find_package(Qt6 REQUIRED COMPONENTS Protobuf)
target_link_libraries(mytarget PRIVATE Qt6::Protobuf)
					

更多细节，见 构建采用 CMake 概述。

文章和指南

• CMake Commands in Qt6 Protobuf
• Protobuf Qt Core Types
• Protobuf Qt GUI Types
• Qt Protobuf Well-Known types

参考

• Qt Protobuf C++ Classes
• Qt Protobuf QML Types

范例

• Qt Protobuf 范例

许可和归属

The Qt Protobuf module is available under commercial licenses from Qt 公司 。此外，它在自由软件许可下也是可用的： GNU LGPL (次一般公共许可) 第 3 版 ，或 GNU GPL (一般公共许可) 第 2 版 ，或 GNU GPL (一般公共许可) 第 3 版 。见 Qt 许可 进一步了解细节。

Furthermore, the qtprotobufgen tool in Qt 6.7.2 may contain third party modules under the following permissive licenses:

protobuf, version 21.9

BSD 3 条款新 (或修订) 许可

内容

• 概述

• What are protocol buffers?

• Which problems do protocol buffers solve?

• What are the benefits of using Qt Protobuf?

• Incoming features

• 使用模块

• QML API

• C++ API

• 文章和指南

• 参考

• 范例

• 许可和归属