libobs via node bindings

This library intends to provide bindings to obs-studio's internal library, named libobs accordingly, for the purpose of using it from a node runtime. Currently, only Windows is supported.

Why CMake?

CMake offers better compatibility with existing projects than node-gyp and comparable solutions. It's also capable of generating solution files for multiple different IDEs and compilers, which makes it ideal for a native module. Personally, I don't like gyp syntax or the build system surrounding it or the fact it requires you to install python.

Building

Prerequisites

You will need to have the following installed:

Windows

Building on windows requires additional software:

Visual Studio 2017 or 2015
Windows SDK (may be installed with Visual Studio 2017 Installer)

Example Build

We use a flexible cmake script to be as broad and generic as possible in order to prevent the need to constantly manage the cmake script for custom uses, while also providing sane defaults. It follows a pretty standard cmake layout and you may execute it however you want.

Example:

yarn install
git submodule update --init --recursive
mkdir build
cd build
cmake .. -G"Visual Studio 15 2017" -A x64
cmake --build .
cpack -G ZIP

This will will download any required dependencies, build the module, and then place it in an archive compatible with npm or yarn that you may specify in a given package.json.

Custom OBS Build

By default, we download a pre-built version of libobs if none is specified. However, this pre-built version may not be what you want to use or maybe you're testing a new obs feature.

You may specify a custom archive of your own. However, some changes need to be made to obs-studio's default configuration before building:

ENABLE_SCRIPTING must be set to false
ENABLE_UI must be set to false
QTDIR should not be specified.

If you don't know how to build obs-studio from source, you may find instructions here.

Example (from root of obs-studio repository clone):

mkdir build
cd build
cmake .. -DENABLE_UI=false -DDepsPath="C:\Users\computerquip\Projectslibobs-deps\win64" -DENABLE_SCRIPTING=false -G"Visual Studio 15 2017" -A x64
cmake --build .
cpack -G ZIP

This will create an archive that's compatible with obs-studio-node. The destination of the archive will appear after cpack is finished executing.

Example:

CPack: Create package using ZIP

CPack: Install projects

CPack: - Install project: obs-studio

CPack: Create package

CPack: - package: C:/Users/computerquip/Projects/obs-studio/build/obs-studio-x64-22.0.3-sl-7-13-g208cb2f5.zip generated.

This archive may then be specified as a cmake variable when building obs-studio-node like so:

cmake .. -G"Visual Studio 15 2017" -A x64 -DOSN_LIBOBS_URL="C:/Users/computerquip/Projects/obs-studio/build/obs-studio-x64-22.0.3-sl-7-13-g208cb2f5.zip"
cmake --build .
cpack -G ZIP

Further Building

I don't specify every possible combination of variables. Here's a list of actively maintained variables that control how obs-studio-node is built:

All configurable node-cmake variables found here.
OSN_LIBOBS_URL - Controls where to fetch the libobs archive. May be a directory, any compressed archive that cpack supports, or a URI of various types including FTP or HTTP/S.

If you find yourself unable to configure something about our build script or have any questions, please file a github issue!

define EXTENDED_DEBUG_LOG controls logging of ipc requests.

Static code analyzis

cppcheck

Install cppcheck from http://cppcheck.sourceforge.net/ and add cppcheck folder to PATH To run check from console:

cd build 
cmake --build . --target CPPCHECK

Also target can be built from Visula Studio. Report output format set as compatible and navigation to file:line posiible from build results panel.

Some warnings suppressed in files obs-studio-client/cppcheck_suppressions_list.txt and obs-studio-server/cppcheck_suppressions_list.txt.

Clang Analyzer

Ninja and LLVM have to be installed in system. Warning: depot_tool have broken ninja.
To make build open cmd.exe.

mkdir build_clang
cd build_clang

"c:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\amd64\vcvars64.bat"
 
set CCC_CC=clang-cl
set CCC_CXX=clang-cl
set CC=ccc-analyzer.bat
set CXX=c++-analyzer.bat
#set CCC_ANALYZER_VERBOSE=1

#make ninja project 
cmake  -G "Ninja" -DCLANG_ANALYZE_CONFIG=1 -DCMAKE_INSTALL_PREFIX:PATH=""  -DCMAKE_LINKER=lld-link -DCMAKE_BUILD_TYPE="Debug"   -DCMAKE_SYSTEM_NAME="Generic" -DCMAKE_MAKE_PROGRAM=ninja.exe ..

#try to build and "fix" errors 
ninja.exe 

#clean build to scan 
ninja.exe clean 

scan-build --keep-empty -internal-stats -stats -v -v -v -o check ninja.exe

Step with "fixing" errors is important as code base and especially third-party code are not ready to be build with clang. And files which failed to compile will not be scanned for errors.

Tests

The tests for obs studio node are written in Typescript and use Mocha as test framework, with electron-mocha pacakage to make Mocha run in Electron, and Chai as assertion framework.

You need to build obs-studio-node in order to run the tests. You can build it any way you want, just be sure to use CMAKE_INSTALL_PREFIX to install obs-studio-node in a folder of your choosing. The tests use this variable to know where the obs-studio-node module is. Since we use our own fork of Electron, you also need to create an environment variable called ELECTRON_PATH pointing to where the Electron binary is in the node_modules folder after you run yarn install. Below are three different ways to build obs-studio-node:

Terminal commands

In obs-studio-node root folder:

yarn install
git submodule update --init --recursive --force
mkdir build
cmake -Bbuild -H. -G"Visual Studio 15 2017" -A x64 -DCMAKE_INSTALL_PREFIX="path_of_your_choosing"
cmake --build build --target install

Terminal using package.json scripts

In obs-studio-node root folder:

mkdir build
yarn local:config
yarn local:build
Optional: To clean build folder to repeat the steps 2 to 3 again do yarn local:clean

CMake GUI

yarn install
Create a build folder in obs-studio-node root
Open CMake GUI
Put obs-studio-node project path in Where is the source code: box
Put path to build folder in Where to build the binaries: box
Click Configure
Change CMAKE_INSTALL_PREFIX to a folder path of your choosing
Click Generate
Click Open Project to open Visual Studio and build the project there

Running tests

Some tests interact with Twitch and we use a user pool service to get users but in case we are not able to fetch a user from it, we use the stream key provided by an environment variable. Create an environment variable called SLOBS_BE_STREAMKEY with the stream key of a Twitch account of your choosing.

To run all the tests do yarn run test
To run only run one test do yarn run test --grep describe_name_value where describe_name_value is the name of the test passed to the describe call in each test file. Example: yarn run test --grep nodeobs_api