Firebase C++ Open Source Development

The repository contains the Firebase C++ SDK source, with support for Android, iOS, and desktop platforms. It includes the following Firebase libraries:

Firebase is an app development platform with tools to help you build, grow and monetize your app. More information about Firebase can be found at https://firebase.google.com.

More information about the Firebase C++ SDK can be found at https://firebase.google.com/docs/cpp/setup. Samples on how to use the Firebase C++ SDK can be found at https://github.com/firebase/quickstart-cpp.

Getting Started

You can clone the repo with the following command:

git clone https://github.com/firebase/firebase-cpp-sdk.git

Prerequisites

The following prerequisites are required for all platforms. Be sure to add any directories to your PATH as needed.

Note: Once python is installed you can use the following commands to install required packages:

  • python -m ensurepip --default-pip
  • python -m pip install --user absl-py
  • python -m pip install --user protobuf

Prerequisites for Desktop

The following prerequisites are required when building the libraries for desktop platforms.

  • OpenSSL, needed for Realtime Database and Cloud Firestore
  • Protobuf, needed for Remote Config

Prerequisites for Windows

Prebuilt packages for openssl can be found using google and if CMake fails to find the install path use the command line option -DOPENSSL_ROOT_DIR=[Open SSL Dir].

Since there are no prebuilt packages for protobuf, getting it working on Windows is a little tricky. The following steps can be used as a guide:

  • Download source zip from github.
  • Extract source and open command prompt to root folder
  • Make new folder vsprojects
  • CD to vsprojects
  • run cmake: cmake ..\cmake -Dprotobuf_BUILD_TESTS=OFF -A Win32
  • Build solution
  • Add command line define to firebase cmake command (see below) -DPROTOBUF_SRC_ROOT_FOLDER=[Source Root Folder]

Note: For x64 builds folder needs to be vsprojects\x64 and change Win32 in cmake command to x64

Prerequisites for Mac

Home brew can be used to install required dependencies:

# https://github.com/protocolbuffers/protobuf/blob/master/kokoro/macos/prepare_build_macos_rc#L20
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
source $HOME/.rvm/scripts/rvm
brew install cmake protobuf python2
sudo chown -R $(whoami) /usr/local

Prerequisites for Android

The following prerequisites are required when building the libraries for Android.

  • Android SDK, Android NDK, and CMake for Android (version 3.10.2 recommended)
    • Download sdkmanager (either independently, or as a part of Android Studio) here
    • Follow these instructions to install the necessary build tools
  • (Windows only) Strings (from Microsoft Sysinternals)

    Important - Strings EULA \ You will have to run Strings once from the command line to accept the EULA before it will work as part of the build process.

Note that we include the Gradle wrapper, which if used will acquire the necessary version of Gradle for you.

Prerequisites for iOS/tvOS

The following prerequisites are required when building the libraries for iOS or tvOS.

Building

Building with CMake

The build uses CMake to generate the necessary build files, and supports out of source builds. The CMake following targets are available to build and link with:

Feature CMake Target
App (base library) firebase_app
AdMob firebase_admob
Google Analytics for Firebase firebase_analytics
Firebase Authentication firebase_auth
Firebase Realtime Database firebase_database
Firebase Dynamic Links firebase_dynamic_links
Cloud Firestore firebase_firestore
Cloud Functions for Firebase firebase_functions
Firebase Invites firebase_invites
Firebase Cloud Messaging firebase_messaging
Firebase Remote Config firebase_remote_config
Cloud Storage for Firebase firebase_storage

For example, to build the Analytics library, you could run the following commands:

mkdir desktop_build && cd desktop_build
cmake ..
cmake --build . --target firebase_analytics

Note that you can provide a different generator on the configure step, for example to generate a project for Visual Studio 2017, you could run:

cmake -G “Visual Studio 15 2017” ..

More information on generators can be found at https://cmake.org/cmake/help/latest/manual/cmake-generators.7.html.

By default, when building the SDK, the CMake process will download any third party dependencies that are needed for the build. This logic is in cmake/external_rules.cmake, and the accompanying cmake/external/CMakeLists.txt. If you would like to provide your own directory for these dependencies, you can override [[dependency_name]]_SOURCE_DIR and [[dependency_name]]_BINARY_DIR. If the binary directory is not provided, it defaults to the given source directory, appended with -build.

For example, to provide a custom flatbuffer directory you could run:

cmake -DFLATBUFFERS_SOURCE_DIR=/tmp/flatbuffers ..

And the binary directory would automatically be set to /tmp/flatbuffers-build.

Currently, the third party libraries that can be provided this way are:

Library
CURL
FLATBUFFERS
LIBUV
NANOPB
UWEBSOCKETS
ZLIB

Building with CMake for iOS

The Firebase C++ SDK comes with a CMake config file to build the library for iOS platforms, cmake/toolchains/ios.cmake. In order to build with it, when running the CMake configuration pass it in with the CMAKE_TOOLCHAIN_FILE definition. For example, to build the Auth library for iOS, you could run the following commands:

mkdir ios_build && cd ios_build
cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchains/ios.cmake ..
cmake --build . --target firebase_auth

Building with CMake for tvOS

The Firebase C++ SDK comes with a CMake config file to build the library for tvOS platforms, cmake/toolchains/apple.toolchain.cmake. In order to build with it, when running the CMake configuration pass it in with the CMAKE_TOOLCHAIN_FILE definition. For example, to build the Auth library for tvOS, you could run the following commands:

mkdir tvos_build && cd tvos_build
cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchains/apple.toolchain.cmake -DPLATFORM=TVOS ..
cmake --build . --target firebase_auth

Building XCFrameworks for both iOS and tvOS

The Firebase C++ SDK comes with a helper Python script to build XCFrameworks that work for both iOS and tvOS. This is helpful as we can use the same deliverable for both iOS and tvOS targets in the same XCode project.

# Install prereqs (like cocoapods)
./build_scripts/tvos/install_prereqs.sh
python scripts/gha/build_ios_tvos.py -s . -b ios_tvos_build

Building with Gradle for Android

When building the Firebase C++ SDK for Android, gradle is used in combination with CMake when producing the libraries. Each Firebase feature is its own gradle subproject off of the root directory. The gradle target to build the release version of each Firebase library is:

Feature Gradle Target
App (base library) :app:assembleRelease
AdMob :admob:assembleRelease
Google Analytics for Firebase :analytics:assembleRelease
Firebase Authentication :auth:assembleRelease
Firebase Realtime Database :database:assembleRelease
Firebase Dynamic Links :dynamic_links:assembleRelease
Cloud Firestore :firestore:assembleRelease
Cloud Functions for Firebase :functions:assembleRelease
Firebase Invites :invites:assembleRelease
Firebase Cloud Messaging :messaging:assembleRelease
Firebase Remote Config :remote_config:assembleRelease
Cloud Storage for Firebase :storage:assembleRelease

For example, to build the release version of the Analytics library, you could run the following from the root directory:

./gradlew :analytics:assembleRelease

Proguard File Generation

Note that as part of the build process, each library generates a proguard file that should be included in your application. The generated file is located in each library’s build directory. For example, the Analytics proguard file would be generated to analytics/build/analytics.pro.

Testing

Each Firebase SDK in this repo includes a series of unit tests. These tests are built and executed by the CI system in order to validate changes and pull requests.

The provided test_windows_x32.bat, test_windows_x64.bat, test_linux.sh and test_mac_x64.sh scripts build the SDKs and execute the unit tests via ctest on Windows32, Windows64, Linux and MacOS hosts, respectively. These scripts reside in the base directory of the repository.

Known Issues

  • Mac
    • When executing tests you may be requested to unlock your Mac OS keychain. Please enter your keychain password and select Always Allow. If you still encounter repeated access request dialogs then you must unlock the keychain manually otherwise some tests will fail.
      • Open the Keychain access application on your Mac.
      • Under Keychains (upper left) select the login keychain.
      • Under Category select Passwords as a category (lower left) and find the entry not_a_real_project_id.{hashcode}. Right click it.
      • Select Get Info, select Access Control and enable the Allow all applications to access this item radio button.
      • Re-run the tests.

Including in Projects

Including in CMake Projects

Including the Firebase C++ SDK to another CMake project is fairly straightforward. In the CMakeLists.txt file that wants to include the Firebase C++ SDK, you can use add_subdirectory, providing the location of the cloned repository. For example, to add Analytics, you could add the following to your CMakeLists.txt file:

add_subdirectory( [[Path to the Firebase C++ SDK]] )
target_link_libraries( [[Your CMake Target]] firebase_analytics firebase_app)

Additional examples of how to do this for each library are available in the C++ Quickstarts.

Including in Android Gradle Projects

In order to link the Firebase C++ SDK with your gradle project, in addition to the CMake instructions above, you can use Android/firebase_dependencies.gradle to link the libraries, their dependencies, and the generated proguard files. For example, to add Analytics, you could add the following to your build.gradle file:

apply from: “[[Path to the Firebase C++ SDK]]/Android/firebase_dependencies.gradle”
firebaseCpp.dependencies {
  analytics
}

Additional examples of how to do this for each library are available in the C++ Quickstarts.