mailio is a cross platform C++ library for MIME format and SMTP, POP3 and IMAP protocols. It is based on the standard C++ 17 and Boost library.
To send a mail, one has to create message
object and set it's attributes as author, recipient, subject and so on. Then, an SMTP connection
is created by constructing smtp
(or smtps
) class. The message is sent over the connection:
message msg;
msg.from(mail_address("mailio library", "mailio@gmail.com"));
msg.add_recipient(mail_address("mailio library", "mailio@gmail.com"));
msg.subject("smtps simple message");
msg.content("Hello, World!");
smtps conn("smtp.gmail.com", 587);
conn.authenticate("mailio@gmail.com", "mailiopass", smtps::auth_method_t::START_TLS);
conn.submit(msg);
To receive a mail, a message
object is created to store the received message. Mail can be received over POP3 or IMAP, depending of mail server setup.
If POP3 is used, then instance of pop3
(or pop3s
) class is created and message is fetched:
pop3s conn("pop.mail.yahoo.com", 995);
conn.authenticate("mailio@yahoo.com", "mailiopass", pop3s::auth_method_t::LOGIN);
message msg;
conn.fetch(1, msg);
Receiving a message over IMAP is analogous. Since IMAP recognizes folders, then one has to be specified, like inbox:
imaps conn("imap.gmail.com", 993);
conn.authenticate("mailio@gmail.com", "mailiopass", imap::auth_method_t::LOGIN);
message msg;
conn.fetch("inbox", 1, msg);
More advanced features are shown in examples
directory, see below how to compile them.
Note for Gmail users: it might be needed to register mailio as a trusted application. Follow the Gmail instructions to add it and use the generated password for all three protocols.
Note for Zoho users: if 2FA is turned on, then instead of the primary password, the application password must be used. Follow Zoho instructions to add mailio as trusted application and use the generated password for all three protocols.
mailio library is supposed to work on all platforms supporting C++ 17 compiler, Boost 1.81 or newer and CMake build tool. The platforms tested so far are Linux, Windows, FreeBSD, MacOS, Cygwin, MinGW and the compilers are Gcc, Microsoft Visual C++ and Clang.
There are several ways to build mailio: by cloning the repo and using Cmake, by using Vcpkg or xmake.
Ensure that OpenSSL, Boost and CMake are in the path. If they are not in the path, one could use CMake options -DOPENSSL_ROOT_DIR
, -DBOOST_ROOT
and
Boost_INCLUDE_DIRS
to set them. Boost must be built with the OpenSSL support. If it cannot be found in the path, set the path explicitly via library-path
and include
parameters of b2
script (after bootstrap
finishes). Both static and dynamic libraries should be built in the build
directory.
If one wants to specify a non-default installation directory, say /opt/mailio
, then the option -DCMAKE_INSTALL_PREFIX
should be used. If a user does not have
privileges for the default directories, then it must specify one by using this CMake variable.
Other available options are BUILD_SHARED_LIBS
(whether a shared or static library shall be built, by default a shared lib is built),
MAILIO_BUILD_DOCUMENTATION
(if Doxygen documentation is generated, by default is on) and MAILIO_BUILD_EXAMPLES
(if examples are built, by default is on).
From the terminal go into the directory where the library is downloaded to, and execute:
mkdir build
cd ./build
cmake ..
make install
Installing the project ensures that the test project has also the auxiliary files copied, required by several tests.
From the command prompt go into the directory where the library is downloaded, and execute:
mkdir build
cd .\build
cmake ..
A solution file will be built, open it from Visual Studio and build the project. To install it, build the INSTALL
project of the mailio solution, it copies
also auxiliary files required by several tests.
Open the command prompt by using the open_distro_window.bat
script, and execute:
mkdir build
cd .\build
cmake.exe .. -G "MinGW Makefiles"
make install
Install Vcpkg and run:
vcpkg install mailio
Tests are not available as an option in this case. Use the CMake way to build them.
The library is tested on valid mail servers, so probably there are negative test scenarios that are not covered by the code. In case you find one, please contact me. Here is a list of issues known so far and planned to be fixed in the future.
Thanks to all people who contribute to the project by improving the source code, report problems and propose new features. Here is a list from the Git history, in case I missed someone please let me know.
In case you find a bug, please drop me a mail to contact (at) alepho.com. Since this is my side project, I'll do my best to be responsive.