The Lightstreamer Client SDKs are a suite of libraries designed to work on different platforms (Web, Node.JS, Android, Java SE, .NET, and Python) but exposing the same API. The project is based on the Haxe language and each native library is derived by transpiling the Haxe code, adding specific code and modules, and wrapping the interfaces. The result is a fully native library for each target platform.
Other platforms are available, which expose the same API but are not derived from this Haxe project. In particular, a Swift SDK is available for Apple platforms.
The API enables any application to communicate bidirectionally with a Lightstreamer Server, that is to subscribe to real-time data pushed by a Server and to send messages to a Server. It offers automatic recovery from connection failures, automatic selection of the best available transport, and full decoupling of subscription and connection operations. It is responsible of forwarding the subscriptions to the Server and re-forwarding all the subscriptions whenever the connection is broken and then reopened.
Further on the Web and Android platforms the API offers support for Web and Mobile Push Notifications (MPN) by means of the Apple Push Notification Service (APNs) and the Firebase Cloud Messaging (FCM). While real-time subscriptions deliver their updates via the client connection, MPN subscriptions deliver their updates via push notifications, even when the application is offline. They are handled by a special module of the Server, the MPN Module, that keeps them active at all times and continues pushing with no need for a client connection. However, push notifications are not real-time, they may be delayed by the service provider and their delivery is not guaranteed.
The Lightstreamer Client SDKs are written in Haxe, an open-source programming language and cross compiler that allows the compilation of a single code-base to multiple targets.
The source files are hosted on Github.
git clone https://github.com/Lightstreamer/Lightstreamer-lib-client-haxe.gitTo build the supported targets, follow the instructions below. All the commands need to be issued from the folder containing the cloned project.
To set up a Haxe 4.3.4+ development environment, first you need to install the following tools:
- node.js 20.11+ and npm CLI 10.2.4+ (which is bundled with node.js)
- lix, a package manager for Haxe.
lix is installed through npm:
npm install -g lix
To install the right versions of Haxe dependencies and to fetch the project specific Haxe version, enter the command
lix download
You can check the installation with typing haxe --version. You should get an output like 4.3.4.
WARNING It has been observed that lix may occasionally not work as expected. Should you experience any anomalies, the following steps are recommended:
- Uninstall lix from your system:
npm uninstall -g lix - Manually install Haxe
- Install the project dependencies by executing
haxelib install --always tools/deps.hxmlwithin the project directory
In order to build the SDKs you need a few other tools.
First enter the command
npm install
Then install Ant 1.10+, a Java-based build tool (you will also need a JDK 8+ installed on your system).
You can check the installation with typing ant -version. You should get an output like Apache Ant(TM) version 1.10.12 compiled on October 13 2021.
In order to build the Web Client SDK run the commands
cd tools/web
ant
The generated libraries are saved in bin/web/build/dist/npm.
The folder contains a variety of formats to suit the needs of the major development flavors.
| UMD | CommonJS | ES Module | |
|---|---|---|---|
| Full | lightstreamer.js lightstreamer.min.js |
lightstreamer.common.js | lightstreamer.esm.js |
| Core | lightstreamer-core.js lightstreamer-core.min.js |
lightstreamer-core.common.js | lightstreamer-core.esm.js |
| MPN | lightstreamer-mpn.js lightstreamer-mpn.min.js |
lightstreamer-mpn.common.js | lightstreamer-mpn.esm.js |
-
Full: builds with all the modules in the SDK
-
Core: builds with only the core modules (Widgets and Mobile Push Notifications are excluded)
-
MPN: builds with the core modules and Mobile Push Notifications (Widgets are excluded)
-
UMD: UMD builds can be used directly in the browser via a
<script>tag. -
CommonJS: CommonJS builds are intended for use with older bundlers like Browserify or Webpack 1.
-
ES Module: ES module builds are intended for use with modern bundlers like Webpack 2+ or Rollup.
In order to shrink the size of the library, it is possible to substitute the log messages produced by the library when the internal logger is enabled with numeric codes referring to a logmap, that is a json file keeping track of the mapping between the numeric codes and the original messages.
To strip the log messages and generate a logmap, set to true the properties LS_STRIP_LOGS in the file tools/web/build.xml.
To decode an encoded log file, invoke the script tools/decode-logs.js passing as arguments the encoded log file and the logmap file generated by the build script. The decoded log is printed to the console.
For example:
node decode-logs log.txt logmap.json
In order to build the Node.js Client SDK run the commands
cd tools/node
ant
The generated libraries are saved in bin/node/build/dist/npm.
If not already installed, install Ant Ivy 2.5.0+ (see the section named Manually and follow the instructions about Ant 1.6 or superior).
Then install the Android toolkit.
Once installed, get the Android SDK Platform 11 (R) API Level 30 (if you have Android Studio, open the SDK Manager and go to the tab SDK Platforms).
Finally make sure the environment variable ANDROID_HOME points to the Android home folder.
Finally download Bouncy Castle 1.72 cryptographic libraries and copy the files bcprov-jdk18on-172.jar (the cryptography provider) and bcpg-jdk18on-172.2.jar (the GPG driver) to the folder ANT_HOME/lib.
In order to build the Android Client SDK run the commands
cd tools/android
ant
The generated library ls-android-client.jar is saved in the folder bin/android/build/lib.
If not already installed, install Ant Ivy 2.5.0+ (see the section named Manually and follow the instructions about Ant 1.6 or superior).
Then download Bouncy Castle 1.72 cryptographic libraries and copy the files bcprov-jdk18on-172.jar (the cryptography provider) and bcpg-jdk18on-172.2.jar (the GPG driver) to the folder ANT_HOME/lib.
In order to build the Java SE Client SDK run the commands
cd tools/java
ant
The generated library ls-javase-client.jar is saved in the folder bind/java/build/lib.
If not already installed, install .NET SDK 6.0+ and NuGet 6.2+ (get the version for windows or the version for linux/mac).
In order to build the .NET Client SDK run the commands
cd tools/cs
ant
The generated nuget package is saved in the folder bin/cs/dist.
If not already installed, install Python 3.7+.
In order to build the Python Client SDK run the commands
cd tools/python
ant
The generated package is saved in the folder bin/python/build/lib.
Initial Project Setup
If you're setting up the project for the first time, execute the command:
haxelib run hxcpp
Should you be prompted to rebuild the hxcpp tool, please respond with "yes".
Building the Lightstreamer Client SDK
The following notes assume that your system has a C++ toolchain installed, such as g++, clang++, or MSVC++. If not, it is recommended to install the latest Xcode from the App Store on Mac, use the system package manager to install the compilers on Linux, or use Microsoft Visual Studio on Windows. The installed compiler must support the C++17 standard.
Navigate to the tools/cpp directory and run the following command to build the SDK:
ant -e -Dbuild.settings=<hxml-file>
Replace <hxml-file> with the path to your configuration file. You can find a selection of pre-defined configuration files for common systems within the tools/cpp/res directory. These files are organized by operating system and specify whether you're building a debug or release version, and whether you're compiling a dynamic or static library. Omitting the build.settings flag defaults to constructing a dynamic debug library for your current operating system.
Warning
Before building the library, carefully review the configuration files you want to use, as the default settings may not be suited to your system.
For example, to compile a dynamic library with debug symbols for macOS, use:
ant -e -Dbuild.settings=tools/cpp/res/build.mac.debug.hxml
The resulting library will be placed in the bin/cpp directory, under an OS-specific subfolder. Specifically, the command above will generate lightstreamer_clientd.dylib in bin/cpp/mac/debug.
HXML files
Haxe HXML files are configuration files used in Haxe development projects. By grouping compiler arguments together, they make it easier to maintain and manage build configurations.
HXML files contain two primary types of arguments:
-
Haxe Flags: These are utilized by the Haxe compiler to direct the conversion of Haxe code into C++ code. They are essential for defining the structure and behavior of the generated C++ output.
-
Hxcpp Flags: These are specific to the hxcpp tool, which is responsible for the actual compilation of the C++ code. Within these flags, some are directly interpreted by hxcpp to manage the compilation process, while others are passed on to the underlying C++ compiler (such as clang, gcc, or msvc) that hxcpp invokes to compile the generated C++ files.
For our purposes, the most important flags are those pertaining to the C++ compiler and linker.
These flags are organized into four distinct groups of symbols:
-
CXXFLAG_<num>: These are compiler flags for C++. They dictate various compiler settings and optimizations. -
CPPFLAG_<num>: Preprocessor flags for C++. They typically inform the preprocessor about the locations of header files. -
LDFLAG_<num>: Linker flags. Commonly used to define the library search paths during the linking stage. -
LDLIB_<num>: Additional linker flags. These are used to specify the actual libraries to be linked with the Lightstreamer Client SDK.
Here, <num> represents a single digit ranging from 0 to 9.
Keep in mind that each symbol must define a single flag. For instance CXXFLAG_0=-x is an appropriate definition, whereas CXXFLAG_0=-x -y may confuse the compiler and therefore must be avoided.
If the compiler option is a key-value pair, each component must appear in a distinct flag. For example the option -o a.out must be written as
-D CXXFLAG_0=-o
-D CXXFLAG_1=a.out
The syntax for these flags varies based on the toolchain being used. For practical examples, refer to the build configurations located in tools/cpp/res.
A list of the most common flags is the following. For more information, refer to the documentation of Haxe and Hxcpp.
--debug: Add debug symbols to the generated library.-D HXCPP_ARM64: Compile for ARM64 architecture. Other options areHXCPP_M32andHXCPP_M64for 32-bit and 64-bit Intel/AMD architectures.--cpp <path>: Store the generated source files and binaries in the specified path.-D HAXE_OUTPUT_FILE=<file name>: Use the given name (without the file extension part) as the name of the generated library.-D LDLIB_EXT=<ext>: Use the given file extension as the extension of the generated library. Example:.so(don't forget the leading dot). If omitted, the default system extension is used.-D dll_link: Create a dynamic library. To create a static library, use-D static_link. If omitted, an executable file is generated.-D NO_PRECOMPILED_HEADERS: Don't precompile the header files. If omitted, the default behavior depends on the compiler toolchain. Usually the headers are not precompiled, except by MSVC.-D windows: (Windows only) Add this flag if the compilation is for Windows.-D ABI=<option>: (Windows only) Use the multithread dynamic/static version of the C++ standard runtime library. The possible values are:/MD,/MT,/MDdand/MTd. See the MSVC docs for an explanation.-D CXXFLAG_<num>=<option>: Add a compiler flag. Example:-D CXXFLAG_0=-O2.-D CPPFLAG_<num>=<option>: Add a preprocessor flag. Example:-D CPPFLAG_0=-I/usr/local/include.-D LDFLAG_<num>=<option>: Add a linker flag. Example:-D LDFLAG_0=-L/usr/local/lib.-D LDLIB_<num>=<option>: Add a library to be linked. Example: =-D LDLIB_0=-lssl.
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