Creating a socket.io CPP client no possible with SSL/TSL (SIO_TLS) enabled

[LudwigBloder]

I followed the basic instructions to build a CPP Client 'without cmake' (https://github.com/socketio/socket.io-client-cpp/blob/master/INSTALL.md#without-cmake) and then tried enable 'SSL/TSL' following the basic instructions found in 'sio_client_impl.cpp':

#if SIO_TLS
// If using Asio's SSL support, you will also need to add this #include.
// Source: http://think-async.com/Asio/asio-1.10.6/doc/asio/using.html
// #include <asio/ssl/impl/src.hpp>
#endif

Due to this instructions I also was asked to switch from 'ASIO_STANDALONE' to 'ASIO_SEPARATE_COMPILATION', which in turn forced me to include 'boost' and 'boost/asio' as well as 'OpenSSL' into my include path and to disable 'socket.io-client-cpp/lib/asio/asio/include' from the same.

As it turned out, apparently the 'socket.io-client-cpp' package (version 0.8.2 ?), is not compliant with the most recent boost structure changes concerning the location of 'asio/error_code.hpp' which now seems to be located at 'boost/system'.

Please advice where I can find correct instructions to enable SSL/TSL support, or otherwise, please let me know if the is any chance that this problem gets solved by the owner of this GitHub project.

Thanks and best regards

Ludwig

Used include path:
../../Vendor/boost/1.78
../../Vendor/boost/1.78/boost
../../Vendor/OpenSource/OpenSSL/1.1.1m/include
../socket.io-client-cpp/lib/rapidjson/include
../socket.io-client-cpp/lib/websocketpp
xxxx_../socket.io-client-cpp/lib/asio/asio/include

Used preprocessor settings:
WIN32
_DEBUG
_CONSOLE
_BOOST_DATE_TIME_NO_LIB
_BOOST_REGEX_NO_LIB
ASIO_SEPARATE_COMPILATION
xxxxx_ASIO_STANDALONE
WEBSOCKETPP_CPP11_STL
WEBSOCKETPP_CPP11_FUNCTIONAL
SIO_TLS

[jmigual]

Why did you switch to ASIO_SEPARATE_COMPILATION ? The instructions state to use ASIO_STANDALONE. Boost is not needed for this project.

Also, can you verify the socket.io C++ version that you are using? There is no version 0.8.2 and the latest one is 3.1.0. Could you try with the latest master commit as well?

[LudwigBloder]

If I need SSL support, the following instruction can be found:

#if SIO_TLS
// If using Asio's SSL support, you will also need to add this #include.
// Source: http://think-async.com/Asio/asio-1.10.6/doc/asio/using.html
#include <asio/ssl/impl/src.hpp>
#endif

This in turn results in a compile error that 'ASIO_STANDALONE' is not allowed. Therefore I tried out 'ASIO_SEPARATE_COMPILATION' because this is the only way to ensure that 'ASIO_STANDALONE' is not set 'behind the scenes'.

As for the version 0.8.2 I was not precise: it indicates the WebSocket++ version. Sorry for that.

In the meantime, I try using 'socket.io-client-cpp' with a different installation approach, i.e. via 'vcpkg' instead of the following the 'Without CMake' instructions.

Thanks for your support.

[jmigual]

Ah I see. Which asio version are you using? I see from the project submodule that we are using chriskohlhoff/asio@230c0d2 as the commit fro asio. Check also all the submodules and make sure that you are using the same version as the submodule commit version.

Those versions should be able to compile properly as the CMake can use them.

[LudwigBloder]

I first started with the asio version that comes along if one Git clones recursively 'socket.io-client-cpp' and all its referenced submodules (see https://github.com/socketio/socket.io-client-cpp/blob/master/INSTALL.md#without-cmake). According to the 'readme' file it is V1.11.0. Later I tried to download all modules with there latest versions directly from Github. This results in v1.22.0 for asio.

[jmigual]

Hi, can you provide me with the file that you are using to compile? I cannot replicate your issue so maybe taking a look at what you exactly have will help me.

[LudwigBloder]

Dear Joan Marcè

Please find attached my sample. It builds fine if I follow the instructions you can find here: https://github.com/socketio/socket.io-client-cpp/blob/master/INSTALL.md#without-cmake
However, if I enable 'SIO_TLS' and include code line 7 (#include "asio/ssl/impl/src.hpp") it starts getting 'nasty'.
MySocketIoSample.zip

Thanks for your support.
Ludwig

[jmigual]

Hi, find attached the fixed project. The difference is in the MySocketIoSample.vcxproj file. You were missing the include and linking flags for the OpenSSL library. Check out the added line:

<ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <ClCompile>
      <WarningLevel>Level3</WarningLevel>
      <SDLCheck>true</SDLCheck>
      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;SIO_TLS;BOOST_DATE_TIME_NO_LIB;BOOST_REGEX_NO_LIB;ASIO_STANDALONE;_WEBSOCKETPP_CPP11_STL_;_WEBSOCKETPP_CPP11_FUNCTIONAL_;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <ConformanceMode>true</ConformanceMode>

      <!-- Here I've added the include directories of the OpenSSL library -->
      <AdditionalIncludeDirectories>C:\Program Files %28x86%29\OpenSSL-Win32\include;socket.io-client-cpp/src;socket.io-client-cpp/lib/rapidjson/include;socket.io-client-cpp/lib/websocketpp;socket.io-client-cpp/lib/asio/asio/include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
    </ClCompile>
    <Link>
      <SubSystem>Console</SubSystem>
      <GenerateDebugInformation>true</GenerateDebugInformation>

      <!-- This was missing -->
      <AdditionalDependencies>libcrypto32MDd.lib;libssl32MDd.lib;%(AdditionalDependencies)</AdditionalDependencies>
    </Link>
</ItemDefinitionGroup>

MySocketIoSample.zip

Note that I used the 32 bit library as that was your project definition but you should use the 64 bit if you are on a 64 bit plaftorm.

I'm closing the issue as I consider it solved.

[LudwigBloder]

Thanks a lot, Joan Marcè, for your help.

In the end, all boils down to the fact that actually the remark in 'sio_client_impl.cpp' (line 22-26) is incorrect or at least is misleading. It demands that '#include <asio/ssl/impl/src.hpp>' be included in one of the source files if SSL/TSL support is needed. Maybe it makes sense to eliminate these lines from the source file to prevent such misunderstandings in the future.

Thanks again for your valuable help and best regards

Ludwig

[jmigual]

Indeed the comment is incorrect. The only needed thing is the SIO_TLS define