qt_add_grpc | Qt GRPC | Qt 6.9.0 (original) (raw)

Generates Qt-based C++ services using a protobuf schema

Note: This command is in technology preview and may change in future releases.

This command was introduced in Qt 6.5.

Usually qtgrpcgen is invoked through the qt_add_grpc CMake macro.

qt_add_grpc( <CLIENT|SERVER> PROTO_FILES ... [PROTO_INCLUDES ...] [QML] [OUTPUT_DIRECTORY ] [GENERATE_PACKAGE_SUBFOLDERS] [COPY_COMMENTS] [EXPORT_MACRO ] [OUTPUT_HEADERS ] [OUTPUT_TARGETS ] [HEADER_GUARD <pragma|filename>] )

Note: Only CLIENT code generation is currently supported.

The source files are created by qtgrpcgen and added to the target. If the target already exists, the files are added to the target source list. If the target doesn't exist, it is created as a library which you must link to.

The gRPC™ library that is generated using the qt_add_grpc command refers to the protobuf symbols that are used in service calls. This means you either need to use a common target in both qt_add_protobuf and qt_add_grpc calls or link the generated protobuf library to the gRPC one.

Considering the above statement you may reuse the target for both protobuf and gRPC client code:

Generate the protobuf types first

qt_add_protobuf(test_service_client PROTO_FILES test_service.protobuf ) ...

Reuse the protobuf target and extend it with \gRPC client

functionality

qt_add_grpc(test_service_client CLIENT PROTO_FILES test_service.protobuf )

If you want to have separate targets then you need to link the gRPC client target to the protobuf one:

Generate the protobuf types first

qt_add_protobuf(test_service_protobuf PROTO_FILES test_service.protobuf ) ...

Add separate target with the generated code of the \gRPC client.

qt_add_grpc(test_service_client CLIENT PROTO_FILES test_service.protobuf ) target_link_libraries(test_service_client PRIVATE test_service_protobuf)

Arguments

• PROTO_FILES specifies the list of .proto files used by the code generation procedure.
• PROTO_INCLUDES specifies the list of directories to be searched for protobuf dependencies.
  Note: The location of the PROTO_FILES is implicitly considered part of the protobuf include path.
• QML generates the QML client API for the gRPC service. The argument requires the GrpcQuick Qt component.
  find_package(Qt6 6.8 REQUIRED COMPONENTS Quick Protobuf ProtobufQuick Grpc GrpcQuick)
  ...

Generate the protobuf types

qt_add_protobuf(test_service_client
PROTO_FILES
test_service.protobuf
QML
)
...

Generate \gRPC client functionality

qt_add_grpc(test_service_client CLIENT
PROTO_FILES
test_service.protobuf
QML
)

• OUTPUT_DIRECTORY defines the directory where the generated files will be placed. By default, the current build directory is used.
• GENERATE_PACKAGE_SUBFOLDERS uses the package name specifier from the .proto files to create the folder structure for the generated files. For example, if the package is defined as: package io.qt.test, the generated files will be placed in OUTPUT_DIRECTORY/io/qt/test/.
• COPY_COMMENTS copies comments from the .proto files into the generated code.
• EXPORT_MACRO applies only when creating a new shared library from the . This option specifies the base name for the export macro used in the generated code. The final macro name is constructed as QPB_<EXPORT_MACRO>_EXPORT. If this option is not set, the target name is used as EXPORT_MACRO.
  Read Creating Shared Libraries for further in-depth information.
• OUTPUT_HEADERS specifies a variable that will store the list of generated headers. This list can be useful for defining custom project install rules.
• OUTPUT_TARGETS specifies a variable that will store the list of generated targets. This list can be useful for defining custom project install rules.
• HEADER_GUARD specifies the mechanism used for guarding generated header files from multiple inclusion. Possible values are pragma, filename. Defaults to filename. Setting the option to pragma generates the modern pragma header guard:
  Omitting the option or setting the option to filename generates the ifdef wrapping guard, and uses the '.proto' filename as the guard infix:

#ifdef MYMESSAGES_QPB_H
#define MYMESSAGES_QPB_H
...
#endif // MYMESSAGES_QPB_H
Select the preferred guard style according to your project structure.

See also The qtgrpcgen Tool.

CMake Commands

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