Build a widget

config.xml.in file

To build a widget you need a config.xml file describing what is your apps and how Application Framework would launch it. This repo provide a simple default file config.xml.in that should work for simple application without interactions with others bindings.

It is recommended that you use the sample one which is more complete. You can find it at the same location under the name config.xml.in.sample (stunning isn’t it). Just copy the sample file to your conf.d/wgt directory and name it config.xml.in, then edit it to fit your needs.

CAUTION : The default file is only meant to be use for a simple widget app, more complicated ones which needed to export their api, or ship several app in one widget need to use the provided config.xml.in.sample which had all new Application Framework features explained and examples.

Using cmake template macros

To leverage all cmake templates features, you have to specify properties on your targets. Some macros will not works without specifying which is the target type.

As the type is not always specified for some custom targets, like an HTML5 application, macros make the difference using LABELS property.

Choose between:

  • BINDING: Shared library that be loaded by the AGL Application Framework
  • BINDINGV2: Shared library that be loaded by the AGL Application Framework This has to be accompagnied with a JSON file named like the ${OUTPUT_NAME}-apidef of the target that describes the API with OpenAPI syntax (e.g: mybinding-apidef). Or Alternatively, you can choose the name, without the extension, using macro set_openapi_filename. If you use C++, you have to set PROJECT_LANGUAGES to CXX.
  • BINDINGV3: Shared library that be loaded by the AGL Application Framework This has to be accompagnied with a JSON file named like the ${OUTPUT_NAME}-apidef of the target that describes the API with OpenAPI syntax (e.g: mybinding-apidef). Or Alternatively, you can choose the name, without the extension, using macro set_openapi_filename. If you use C++, you have to set PROJECT_LANGUAGES to CXX.
  • PLUGIN: Shared library are meant to be used as a binding plugin. A binding would load it as a plugin to extend its functionnalities. It should be named with a special extension that you choose with SUFFIX cmake target property or it’d be .ctlso by default.
  • HTDOCS: Root directory of a web app. This target has to build its directory and puts its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
  • DATA: Resources used by your application. This target has to build its directory and puts its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
  • EXECUTABLE: Entry point of your application executed by the AGL Application Framework
  • LIBRARY: An external 3rd party library bundled with the binding for its own purpose because platform doesn’t provide it.
  • BINDING-CONFIG: Any files used as configuration by your binding.

Optional LABELS are available to define which resources type your test materials are:

  • TEST-CONFIG: JSON configuration files that will be used by the afb-test binding to know how to execute tests.
  • TEST-DATA: Resources used to test your binding. It is at least your test plan and also could be fixtures and any needed files by your tests. These files will appear in a separate test widget.
  • TEST-PLUGIN: Shared library are meant to be used as a binding plugin. A binding would load it as a plugin to extend its functionalities. It should be named with a special extension that you choose with SUFFIX cmake target property or it’d be .ctlso by default.
  • TEST-HTDOCS: Root directory of a web app. This target has to build its directory and put its files in the ${CMAKE_CURRENT_BINARY_DIR}/${TARGET_NAME}
  • TEST-EXECUTABLE: Entry point of your application executed by the AGL Application Framework
  • TEST-LIBRARY: An external 3rd party library bundled with the binding for its own use in case of platform doesn’t provide it.

Here is a mapping between LABELS and directories where files will be placed in the widget:

  • EXECUTABLE : <wgtrootdir>/bin
  • BINDING-CONFIG : <wgtrootdir>/etc
  • BINDING BINDINGV2 BINDINGV3 LIBRARY : <wgtrootdir>/lib
  • PLUGIN : <wgtrootdir>/lib/plugins
  • HTDOCS : <wgtrootdir>/htdocs
  • BINDING-DATA : <wgtrootdir>/var
  • DATA : <wgtrootdir>/var

And about test dedicated LABELS:

  • TEST-EXECUTABLE : <wgtrootdir>/bin
  • TEST-CONFIG : <TESTwgtrootdir>/etc
  • TEST-PLUGIN : <wgtrootdir>/lib/plugins
  • TEST-HTDOCS : <wgtrootdir>/htdocs
  • TEST-DATA : <TESTwgtrootdir>/var

TIP you should use the prefix afb- with your BINDING* targets which stand for **Application Framework Binding.

Example:

SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
		LABELS "HTDOCS"
		OUTPUT_NAME dist.prod
	)

NOTE: You doesn’t need to specify an INSTALL command for these targets. This is already handle by template and will be installed in the following path : ${CMAKE_INSTALL_PREFIX}/${PROJECT_NAME}

NOTE: if you want to set and use rpath with your target you should use and set the target property INSTALL_RPATH.

Add external 3rd party library

You could need to include an external library that isn’t shipped in the platform. Then you have to bundle the required library in the lib widget directory.

Templates includes some facilities to help you to do so. Classic way to do so is to declare as many CMake ExternalProject as library you need.

An ExternalProject is a special CMake module that let you define how to: download, update, patch, configure, build and install an external project. It doesn’t have to be a CMake project and custom step could be added for special needs using ExternalProject step. More informations on CMake ExternalProject documentation site.

Example to include mxml library for unicens2-binding project:

set(MXML external-mxml)
set(MXML_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/mxml)
ExternalProject_Add(${MXML}
    GIT_REPOSITORY https://github.com/michaelrsweet/mxml.git
    GIT_TAG release-2.10
    SOURCE_DIR ${MXML_SOURCE_DIR}
    CONFIGURE_COMMAND ./configure --build x86_64 --host aarch64
    BUILD_COMMAND make libmxml.so.1.5
    BUILD_IN_SOURCE 1
    INSTALL_COMMAND ""
)

PROJECT_TARGET_ADD(mxml)

add_library(${TARGET_NAME} SHARED IMPORTED GLOBAL)

SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
    LABELS LIBRARY
    IMPORTED_LOCATION ${MXML_SOURCE_DIR}/libmxml.so.1
    INTERFACE_INCLUDE_DIRECTORIES ${MXML_SOURCE_DIR}
)

add_dependencies(${TARGET_NAME} ${MXML})

Here we define an external project that drive the build of the library then we define new CMake target of type IMPORTED. Meaning that this target hasn’t been built using CMake but is available at the location defined in the target property IMPORTED_LOCATION.

You could want to build the library as SHARED or STATIC depending on your needs and goals. Then you only have to modify the external project configure step and change filename used by IMPORTED library target defined after external project.

Then target LABELS property is set to LIBRARY to ship it in the widget.

Unicens project also need some header from this library, so we use the target property INTERFACE_INCLUDE_DIRECTORIES. Setting that when another target link to that imported target, it can access to the include directories.

We bound the target to the external project using a CMake dependency at last.

Then this target could be use like any other CMake target and be linked etc.

If you already have a binary version of the library that you want to use and you can’t or don’t want to build the library then you only have to add an IMPORTED library target.

So, taking the above example, mxml library inclusion would be:

PROJECT_TARGET_ADD(mxml)

add_library(${TARGET_NAME} SHARED IMPORTED GLOBAL)

SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
    LABELS LIBRARY
    IMPORTED_LOCATION /path/to/library/libmxml.so.1
    INTERFACE_INCLUDE_DIRECTORIES /path/to/mxml/include/dir
)

Finally, you can link any other lib or executable target with this imported library like any other target.

Macro reference

PROJECT_TARGET_ADD

Typical usage would be to add the target to your project using macro PROJECT_TARGET_ADD with the name of your target as parameter.

Example:

PROJECT_TARGET_ADD(low-can-demo)

NOTE: This will make available the variable ${TARGET_NAME} set with the specificied name. This variable will change at the next call to this macros.

project_subdirs_add

This macro will search in all subfolder any CMakeLists.txt file. If found then it will be added to your project. This could be use in an hybrid application by example where the binding lay in a sub directory.

Usage :

project_subdirs_add()

You also can specify a globbing pattern as argument to filter which folders will be looked for.

To filter all directories that begin with a number followed by a dash the anything:

project_subdirs_add("[0-9]-*")

set_openapi_filename

Used with a target labelized BINDINGV2 to define the file name, and possibly a relative path with the current CMakeLists.txt.

If you don’t use that macro to specify the name of your definition file then the default one will be used, ${OUTPUT_NAME}-apidef with OUTPUT_NAME as the target property.

CAUTION you must only specify the name WITHOUT the extension.

set_openapi_filename('binding/mybinding_definition')

add_input_files

Create custom target dedicated for HTML5 and data resource files. This macro provides syntax and schema verification for differents languages which are about now: LUA, JSON and XML.

You could change the tools used to check files with the following variables:

  • XML_CHECKER: set to use xmllint provided with major linux distribution.
  • LUA_CHECKER: set to use luac provided with major linux distribution.
  • JSON_CHECKER: no tools found at the moment.
add_input_file("${MY_FILES_LIST}")

NOTE: an issue at the check step on a file will stop at the build step.