Retrieve Email over SSL connection in Visual C++

In previous section, I introduced how to retrieve email from Exchange Server with WebDAV protocol. In this section, I will introduce how to retrieve email over SSL connection in Visual C++.

Introduction

SSL and TLS

SSL connection encrypts data between the email component and POP3 server or IMAP4 server to protect user, password and email content in TCP/IP level. Now this technology is commonly used and many email servers are deployed with SSL such as Gmail, Yahoo and Hotmail.

There are two ways to deploy SSL on email server:

  • Implicit SSL

    Deploying SSL on another port (POP3: 995 port or IMAP4: 993 port) directly. This is most common way.

  • Explicit SSL (TLS)

    Using STARTTLS or STLS command to switch SSL channel on normal port (POP3: 110 port or IMAP4: 143 port);

EAGetMail POP3 component supports both ways. Please see the following example codes:

For Exchange Web Service/WebDAV protocol, the SSL is based on HTTPS connection, so you just need to set SSLConnection property and simply ignore Port property. Notice: Exchange Web Service requires SSL connection by default.

[Visual C++ Example - SSL/TLS]

const int MailServerPop3 = 0;
const int MailServerImap4 = 1;
const int MailServerEWS = 2;
const int MailServerDAV = 3;

const int ConnectSSLAuto = 0;
const int ConnectSSL = 1;
const int ConnectTLS = 2;

// Retrieve email by normal TCP/IP without SSL connection
// POP3
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("pop3.emailarchitect.net");
oServer->User = _T("test@emailarchitect.net");
oServer->Password = _T("test");
oServer->Protocol = MailServerPop3;

// IMAP4
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("imap4.emailarchitect.net");
oServer->User = _T("test@emailarchitect.net");
oServer->Password = _T("test");
oServer->Protocol = MailServerImap4;
oServer->Port = 143;

// Retrieve email over SSL connection with direct SSL.
// POP3 SSL
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("pop3.emailarchitect.net");
oServer->User = _T("test@emailarchitect.net");
oServer->Password = _T("test");
oServer->Protocol = MailServerPop3;
oServer->SSLConnection = VARIANT_TRUE;
oServer->Port = 995;

// IMAP4 SSL
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("imap4.emailarchitect.net");
oServer->User = _T("test@emailarchitect.net");
oServer->Password = _T("test");
oServer->Protocol = MailServerImap4;
oServer->SSLConnection = VARIANT_TRUE;
oServer->Port = 993;

// Retrieve email by SSL connection with STARTTLS or TLS command switching
// POP3 TLS
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("pop3.emailarchitect.net");
oServer->User = _T("test@emailarchitect.net");
oServer->Password = _T("test");
oServer->Protocol = MailServerPop3;
oServer->SSLConnection = VARIANT_TRUE;
oServer->Port = 110;
oServer->SSLType = ConnectTLS;

// IMAP4 STARTTLS
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("imap4.emailarchitect.net");
oServer->User = _T("test@emailarchitect.net");
oServer->Password = _T("test");
oServer->Protocol = MailServerImap4;
oServer->SSLConnection = VARIANT_TRUE;
oServer->Port = 143;
oServer->SSLType = ConnectTLS;

// WebDAV
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("exch.emailarchitect.net");
oServer->User = _T("emailarchitect.net\\tester");
oServer->Password = _T("test");
oServer->Protocol = MailServerDAV;

// WebDAV SSL
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("exch.emailarchitect.net");
oServer->User = _T("emailarchitect.net\\tester");
oServer->Password = _T("test");
oServer->Protocol = MailServerDAV;
oServer->SSLConnection = VARIANT_TRUE;

// Web Service SSL
IMailServerPtr oServer = NULL;
oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
oServer->Server = _T("exch.emailarchitect.net");
oServer->User = _T("emailarchitect.net\\tester");
oServer->Password = _T("test");
oServer->Protocol = MailServerEWS;
oServer->SSLConnection = VARIANT_TRUE;

Note

Remarks: All of examples in this section are based on first section: A simple Visual C++ project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference to your project.

[Visual C++ Example - Retrieve email from POP3 server over SSL on 995 port]

The following example codes demonstrate how to retrieve emails from POP3 server over SSL connection on 995 port. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

To get the full sample projects, please refer to Samples section.

#include "stdafx.h"

#include "eagetmailobj.tlh"
using namespace EAGetMailObjLib;

int _tmain(int argc, _TCHAR* argv[])
{
    const int MailServerPop3 = 0;
    const int MailServerImap4 = 1;
    const int MailServerEWS = 2;
    const int MailServerDAV = 3;

    // Initialize COM environment
    ::CoInitialize( NULL );

    // Create a folder named "inbox" under current exe file directory
    // to save the emails retrieved.
    TCHAR szPath[MAX_PATH+1];
    memset( szPath, 0, sizeof(szPath));
    ::GetModuleFileName( NULL, szPath,  MAX_PATH );

    // Change file name to current full path
    LPCTSTR psz = _tcsrchr( szPath, _T('\\'));
    if( psz != NULL )
    {
        szPath[psz-szPath] = _T('\0');
    }
    TCHAR szMailBox[MAX_PATH+1];
    memset( szMailBox, 0, sizeof(szMailBox));
    wsprintf( szMailBox, _T("%s\\inbox"), szPath );

    // Create a folder to store emails
    ::CreateDirectory( szMailBox, NULL );

    try
    {
        IMailServerPtr oServer = NULL;
        oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
        oServer->Server = _T("pop3.emailarchitect.net");
        oServer->User = _T("test@emailarchitect.net");
        oServer->Password = _T("testpassword");
        oServer->Protocol = MailServerPop3;

        // Enable SSL connection
        oServer->SSLConnection = VARIANT_TRUE;

        // Set 995 POP3 SSL port
        oServer->Port = 995;

        IMailClientPtr oClient = NULL;
        oClient.CreateInstance(__uuidof(EAGetMailObjLib::MailClient))
        oClient->LicenseCode = _T("TryIt");

        oClient->Connect( oServer );
        _tprintf(_T("Connected\r\n"));

        _variant_t infos = oClient->GetMailInfos();
        SAFEARRAY *psa = infos.parray;
        long LBound = 0, UBound = 0;
        SafeArrayGetLBound( psa, 1, &LBound );
        SafeArrayGetUBound( psa, 1, &UBound );

        INT count = UBound-LBound+1;
        _tprintf(_T("Total %d emails\r\n"), count );

        for( long i = LBound; i <= UBound; i++ )
        {
            _variant_t vtInfo;
            SafeArrayGetElement( psa, &i, &vtInfo );

            IMailInfoPtr pInfo;
            vtInfo.pdispVal->QueryInterface(__uuidof(IMailInfo), (void**)&pInfo);

            TCHAR szFile[MAX_PATH+1];
            memset( szFile, 0, sizeof(szFile));

            // Generate a random file name by current local datetime,
            // You can use your method to generate the filename if you do not like it
            SYSTEMTIME curtm;
            ::GetLocalTime( &curtm );
            ::wsprintf( szFile, _T("%s\\%04d%02d%02d%02d%02d%02d%03d%d.eml"),
                szMailBox,
                curtm.wYear,
                curtm.wMonth,
                curtm.wDay,
                curtm.wHour,
                curtm.wMinute,
                curtm.wSecond,
                curtm.wMilliseconds,
                i );

            // Receive email from POP3 server
            IMailPtr oMail = oClient->GetMail(pInfo);

            // Save email to local disk
            oMail->SaveAs( szFile, VARIANT_TRUE );

            // Mark email as deleted from POP3 server.
            oClient->Delete( pInfo );
        }

        // Delete method just mark the email as deleted,
        // Quit method purge the emails from server exactly.
        infos.Clear();
        oClient->Quit();
    }
    catch( _com_error &ep )
    {
        _tprintf( _T("Error: %s"), (const TCHAR*)ep.Description());
    }

    return 0;
}

[Visual C++ Example - Retrieve email from IMAP4 server over SSL on 993 port]

The following example codes demonstrate how to retrieve emails from IMAP4 server over SSL connection on 993 port. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

To get the full sample projects, please refer to Samples section.

#include "stdafx.h"

#include "eagetmailobj.tlh"
using namespace EAGetMailObjLib;

int _tmain(int argc, _TCHAR* argv[])
{
    const int MailServerPop3 = 0;
    const int MailServerImap4 = 1;
    const int MailServerEWS = 2;
    const int MailServerDAV = 3;

    // Initialize COM environment
    ::CoInitialize( NULL );

    // Create a folder named "inbox" under current exe file directory
    // to save the emails retrieved.
    TCHAR szPath[MAX_PATH+1];
    memset( szPath, 0, sizeof(szPath));
    ::GetModuleFileName( NULL, szPath,  MAX_PATH );

    // Change file name to current full path
    LPCTSTR psz = _tcsrchr( szPath, _T('\\'));
    if( psz != NULL )
    {
        szPath[psz-szPath] = _T('\0');
    }
    TCHAR szMailBox[MAX_PATH+1];
    memset( szMailBox, 0, sizeof(szMailBox));
    wsprintf( szMailBox, _T("%s\\inbox"), szPath );

    // Create a folder to store emails
    ::CreateDirectory( szMailBox, NULL );

    try
    {
        IMailServerPtr oServer = NULL;
        oServer.CreateInstance(__uuidof(EAGetMailObjLib::MailServer));
        oServer->Server = _T("imap.emailarchitect.net");
        oServer->User = _T("test@emailarchitect.net");
        oServer->Password = _T("testpassword");
        oServer->Protocol = MailServerImap4;

        // Enable SSL connection
        oServer->SSLConnection = VARIANT_TRUE;

        // Set 993 IMAP4 SSL port
        oServer->Port = 993;

        IMailClientPtr oClient = NULL;
        oClient.CreateInstance(__uuidof(EAGetMailObjLib::MailClient))
        oClient->LicenseCode = _T("TryIt");

        oClient->Connect( oServer );
        _tprintf(_T("Connected\r\n"));

        _variant_t infos = oClient->GetMailInfos();
        SAFEARRAY *psa = infos.parray;
        long LBound = 0, UBound = 0;
        SafeArrayGetLBound( psa, 1, &LBound );
        SafeArrayGetUBound( psa, 1, &UBound );

        INT count = UBound-LBound+1;
        _tprintf(_T("Total %d emails\r\n"), count );

        for( long i = LBound; i <= UBound; i++ )
        {
            _variant_t vtInfo;
            SafeArrayGetElement( psa, &i, &vtInfo );

            IMailInfoPtr pInfo;
            vtInfo.pdispVal->QueryInterface(__uuidof(IMailInfo), (void**)&pInfo);

            TCHAR szFile[MAX_PATH+1];
            memset( szFile, 0, sizeof(szFile));

            // Generate a random file name by current local datetime,
            // You can use your method to generate the filename if you do not like it
            SYSTEMTIME curtm;
            ::GetLocalTime( &curtm );
            ::wsprintf( szFile, _T("%s\\%04d%02d%02d%02d%02d%02d%03d%d.eml"),
                szMailBox,
                curtm.wYear,
                curtm.wMonth,
                curtm.wDay,
                curtm.wHour,
                curtm.wMinute,
                curtm.wSecond,
                curtm.wMilliseconds,
                i );

            // Receive email from IMAP4 server
            IMailPtr oMail = oClient->GetMail(pInfo);

            // Save email to local disk
            oMail->SaveAs( szFile, VARIANT_TRUE );

            // Mark email as deleted from IMAP4 server.
            oClient->Delete( pInfo );
        }

        // Delete method just mark the email as deleted,
        // Quit method purge the emails from server exactly.
        infos.Clear();
        oClient->Quit();
    }
    catch( _com_error &ep )
    {
        _tprintf( _T("Error: %s"), (const TCHAR*)ep.Description());
    }

    return 0;
}

Next Section

At next section I will introduce how to download emails from Gmail account.

Appendix

Comments

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