qlibssh2

Qt wrapper for libssh2

Introduction

I could not get libssh2 to work properly with QTcpSocket's. Than I found the solution in the Qt ssh classes from project daggy. I decided to isolate the ssh2 related code and make it a small library on it's own: qlibssh2.

How to use

CMake

In the cmake project of your application:

find_package(QLibssh2 REQUIRED CONFIG)

add_executable(example
    main.cpp
    # ...
)

target_link_libraries(example QLIBSSH2::qlibssh2)

The find_package will check that all needed dependencies of this library are installed. These dependencies are libssh2 and Qt5Core, Qt5Network. The libssh2 library has dependencies on OpenSSL and zlib.

API

#include "qlibssh2/Ssh2Client.h"

#include <QtCore/QCoreApplication>

using namespace qlibssh2;

int main(int argc, char *argv[])
{
    QCoreApplication app{argc, argv};

    Ssh2Settings settings;
    Ssh2Client client{settings};

    QObject::connect(&client, &Ssh2Client::sessionStateChanged, [](Ssh2Client::SessionStates state) {
        qDebug() << "state" << state;
    });
    client.connectToHost("[email protected]");

    return app.exec();
}

Build

There are two ways to build this library. The easiest way is with Conan, but the cmake project has been written in a way that Conan is just optional and all the dependencies can also be installed manually. For both methods, first prepare a build environment with your compiler and cmake. The following instructions and examples are based on Windows, but should work similarly on any platform.

Conan

Since this library is a Qt wrapper around libssh2, it is likely you have Qt pre-installed for your application. To build this library with your pre-installed Qt version you will have to define the QTDIR environment variable and set the option local_qt_version. If this option is not defined, conan will build Qt from sources.

Add Conan repository remotes

conan remote add jeruntu https://api.bintray.com/conan/jeruntu/conan
# Optional, required when not using local pre-installed Qt:
conan remote add bincrafters https://api.bintray.com/conan/bincrafters/public-conan

Add this library as a dependency

To use the package in your application / library, add this package as a dependency in conanfile.txt or conanfile.py:

[requires]
qlibssh2/0.1.0 # or any other version

[generators]
cmake_paths
cmake_find_package

Install dependencies for your project

PS cd $YourAppDir
PS md build; cd build

(1) Local pre-installed Qt

PS $Env:QTDIR='C:\Qt\5.15.1\msvc2019_64'
PS conan install .. -o qlibssh2:local_qt_version='5.15.1' --build=missing

To make this fixed, add it to the conanfile.txt and omit the option from the command line:

[options]
qlibssh2:local_qt_version=5.15.1

(2) Or build Qt from sources (takes a while...)

PS conan install .. --build=missing

To change the Qt version override it:

[requires]
qt/5.15.2

Build project

Now that all dependencies are installed by Conan, the project is ready to be build. Pass the generated conan_paths.cmake file on to the main cmake file of your project. For example, a release build with Ninja generator:

PS $Path = "$pwd".Replace('\', '/') # cmake expects forward slashes
PS cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Release `
"-DCMAKE_PROJECT_$($APP_PROJECT_NAME)_INCLUDE=$Path/conan_paths.cmake"
PS cmake --build .

Manually

For libssh2 OpenSSL can be used as the crypto lib. The easiest way is to install it with chocolatey.

PS choco install openssl

Make sure the OpenSSL dll's are in the PATH. Build libssh2:

PS git clone https://github.com/libssh2/libssh2.git
PS cd libssh2
PS build; cd build
PS cmake .. -DBUILD_SHARED_LIBS=OFF
PS cmake --build .

The libssh2 cmake config package will be exported automatically by the cmake build, and can be consumed with find_package. Now build and install this library:

PS git clone https://github.com/Jeruntu/qlibssh2.git
PS cd qlibssh2
PS md build; cd build
PS cmake .. -DCMAKE_PREFIX_PATH="$Env:QTDIR" -DCMAKE_INSTALL_PREFIX="$MyCmakePackageDir"
PS cmake --build .
PS cmake --build . --target install

PS cd $YourAppDir
PS md build; cd build
PS cmake .. -DCMAKE_PREFIX_PATH="$Env:QTDIR;$MyCmakePackageDir"
PS cmake --build .