POP3 client with TLS authentication

Included files:

argparser.cpp
argparser.h
main.cpp
Makefile
mySecuredSocket.cpp
mySecuredSocket.h
mySocket.cpp
mySocket.h

Specification of arguments - help:

    ------  ------  ------  ------  ------
    Usage: popcl <server> [-p <port>] [-T|-S [-c <certfile>] [-C <certaddr>]] [-d] [-n] -a <auth_file> -o <out_dir>
    Arguments order is arbitrary.
    ------  ------  ------  ------  ------
    -p number of port on remote server
    -T (TLS) connect to remote server securely
    -S (STARTTLS) connect to remote server unsecured and initiate secure communication
    -c name of certification file
    -C name of certification directory
    -d delete all messages from server after download
    -n download and save just new messages
    -a name of file with authentication data --required
    -o name of folder where messages will be saved --required
    ------  ------  ------  ------  ------

Known disadvantages of implementation:

• Whole message have to be downloaded to retrieve Message-Id on which is based save and creation of files.
• When non-existing directory is given to client, and no message was downloaded from server, directory will be created either.

Example of using on IPv6 address of seznam.cz POP3 server with TLS encryption

./popcl 2a02:598:a::78:46 -o test_dir_for_email -a auth.conf -T

Example of using on IPv6 address of seznam.cz POP3 server with STARTTLS encryption

./popcl 2a02:598:a::78:46 -o test_dir_for_email -a auth.conf -S

Example of using on IPv4 address of sezanm.cz POP3 server without any encryption

./popcl 77.75.78.46 -o test_dir_for_email -a auth.conf

Example of using on IPv4 address of sezanm.cz POP3 server with TLS encryption and specified folder with certificates

./popcl 77.75.78.46 -o test_dir_for_email -a auth.conf -T -C etc/certs/