New libpurple plugin for Telegram

Motivation

telegram-purple seems to miss incoming messages a lot, thus writing new plugin using latest tdlib.

Functionality

It should be just about usable for private chats.

Debugging vs. privacy

It's good to have debug log at hand whenever a glitch is observed, or to be able to reproduce the glitch with loggin turned on. With pidgin, debug log can be turn on like this:

pidgin -d >&~/pidgin.log

The debug log contains a lot of private information such as names and phone numbers of all contacts, list of all channels you've participated in or text of all sent and received messages. Be mindful of that before posting debug log on the internets. Even just saving debug log to a file can be a questionable idea if there are multiple users on the system (since permissions will be 0644 by default). Such is the nature of debugging instant messaging software.

Building

TDLib should be prebuilt and installed somewhere (requires C++14):

cd <path to TDLib sources>
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make
make install DESTDIR=/path/to/tdlib

Also see building for additional details on TDLib building.

Building this plugin:

mkdir build
cd build
cmake -DTd_DIR=/path/to/tdlib/usr/local/lib/cmake/Td ..
make

Installation

Copy the .so to libpurple plugins directory.

It's good to have telegram-purple installed as well since its icon is used at the moment.

Regression test

Build google test library and make install it somewhere

Run cmake with '-DGTEST_PATH=/path/to/gtest'

make run-tests or test/tests or valgrind test/tests

GPL compatibility: building tdlib with OpenSSL 3.0

OpenSSL versions prior to 3.0 branch have license with advertisement clause, making it incompatible with GPL. If this is a concern, a possible solution is to build with OpenSSL 3.0 which uses Apache 2.0 license.

Building OpenSSL

Remove quotes and spaces from RELEASE_DATE in VERSION.

Replace OPENSSL_VERSION_NUMBER definition with #define OPENSSL_VERSION_NUMBER 0x30000000L in include/openssl/opensslv.h.in (not always necessary, depending on cmake version).

./config --prefix=/path/to/openssl
make
make install
rm /path/to/openssl/lib/*.so*

Building tdlib

Same as usual, but with additional cmake argument -DOPENSSL_ROOT_DIR=/path/to/openssl

If build fails due to linker errors with dlopen etc. not found then

sed 's/tdnet/tdcore tdnet/' -i benchmark/CMakeLists.txt