XOAUTH2 authentication (GMail)

It’s been a while! Today, XOAUTH2 authentication mechanism was implemented into VMime, thanks to Kevin Xi. This SASL authentication mechanism is used by Google GMail.

Here is a brief and simple example of how to use it:

// Indicate that we want to use XOAUTH2 SASL mechanism
    registerMechanism <vmime::security::sasl::XOAuth2SASLMechanism>("XOAUTH2");

// Create a new session
vmime::shared_ptr <vmime::net::session> sess = vmime::net::session::create();

// Use a custom authenticator to force using XOAUTH2 mechanism
vmime::shared_ptr <vmime::security::authenticator> xoauth2Auth =
    vmime::make_shared <vmime::security::sasl::XOAuth2SASLAuthenticator>

// Create a new SMTPS service to GMail
vmime::shared_ptr <vmime::net::transport> tr = sess->getTransport(
    vmime::utility::url("smtps://smtp.gmail.com:465"), xoauth2Auth

tr->setProperty("options.need-authentication", true);
tr->setProperty("auth.username", "your-email@gmail.com");
tr->setProperty("auth.accesstoken", "ya29.5MEMlacTJifpYHHGn3V...your-access-token...kIOWy3wft5Rs");


// Do whatever you want with 'tr' here!

In the previous example, if the XOAUTH2 authentication fails, no other authentication mechanism will be tried. If you want to fall back on basic username/password authentication mechanism if XOAUTH2 fails, simply replace MODE_EXCLUSIVE with MODE_SUGGEST. And don’t forget to also set the auth.password property!

For more information about XOAUTH2, see OAuth 2.0 mechanism on Google Developers page.

How to use the new logging facility?

Last week, logging facility has been added to VMime messaging services. This will allow the developer to trace what is sent and received on the connection between client and server, and may help debugging. We will see in this post how to use this feature, which is supported for IMAP, POP3 and SMTP protocols.

First, you have to create your own tracer, which must implement the vmime::net::tracer interface:

class myTracer : public vmime::net::tracer

    myTracer(const vmime::string& proto, const int connectionId)
        : m_proto(proto), m_connectionId(connectionId)

    // Called by VMime to trace what is sent on the socket
    void traceSend(const vmime::string& line)
        std::cout << "[" << m_proto << ":" << m_connectionId
                  << "] C: " << line << std::endl;

    // Called by VMime to trace what is received from the socket
    void traceReceive(const vmime::string& line)
        std::cout << "[" < < m_proto << ":" << m_connectionId
                  << "] S: " << line << std::endl;


    const vmime::string m_proto;
    const int m_connectionId;

Also create a factory class, used to instanciate your tracer objects:

class myTracerFactory : public vmime::net::tracerFactory

    vmime::shared_ptr <vmime::net::tracer> create
        (vmime::shared_ptr <vmime::net::service> serv,
         const int connectionId)
        return vmime::make_shared <myTracer>
               (serv->getProtocolName(), connectionId);

Next, we have to tell VMime to use it. When you create your service (either store or transport), simply call the setTracerFactory on the service and pass an instance of your factory class:

 vmime::shared_ptr <vmime::net::transport> store =

 // Enable tracing communication between client and server
 store->setTracerFactory(vmime::make_shared <myTracerFactory>());

That’s all! Now, everything which is sent on/received from the socket will be logged using your tracer object. Here is an example of a trace session for IMAP:

[imaps:1] C: a001 AUTHENTICATE PLAIN
[imaps:1] S: + 
[imaps:1] C: {...SASL exchange: 52 bytes of data...}
[imaps:1] C: a002 LIST "" ""
[imaps:1] S: * LIST (\Noselect) "." ""
[imaps:1] S: a002 OK List completed.
[imaps:1] C: a003 CAPABILITY
[imaps:1] S: a003 OK Capability completed.
[imaps:1] C: a003 SELECT INBOX (CONDSTORE)
[imaps:1] S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft $NotJunk NonJunk JunkRecorded $MDNSent NotJunk $Forwarded Junk $Junk Forwarded $MailFlagBit1)
[imaps:1] S: * OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft $NotJunk NonJunk JunkRecorded $MDNSent NotJunk $Forwarded Junk $Junk Forwarded $MailFlagBit1 \*)] Flags permitted.
[imaps:1] S: * 104 EXISTS
[imaps:1] S: * 0 RECENT
[imaps:1] S: * OK [UNSEEN 6] First unseen.
[imaps:1] S: * OK [UIDVALIDITY 1268127585] UIDs valid
[imaps:1] S: * OK [UIDNEXT 32716] Predicted next UID
[imaps:1] S: * OK [HIGHESTMODSEQ 148020] Highest
[imaps:1] S: a003 OK [READ-WRITE] Select completed.

Please note that no sensitive data (ie. login or password) will be traced. Same, “blob” data such as message content or SASL exchanges will be logged as a marker which indicates how many bytes were sent/received (eg. “{…SASL exchange: 52 bytes of data…}”).

New feature: simultaneously get and fetch messages

We have released a new feature for IMAP stores: get and fetch messages in a single operation. This will avoid one round-trip to the server.

Let’s say we want to get the flags for the messages UID 2 to 6. Until today, we used to write the following code:

vmime::shared_ptr <vmime::net::folder> f = /* ... */;

vmime::net::messageSet mset(vmime::net::messageSet::byUID(2, 6));

vmime::net::fetchAttributes attribs;

std::vector <vmime::shared_ptr <vmime::net::message> >
    msgs = f->getMessages(mset);

f->fetchMessages(msgs, attribs);

// ...do something with msg[n]->getFlags()...

This resulted into the following IMAP client-server dialog, with two FETCH commands in sequence:

C: a005 UID FETCH 2:6 UID                <-- getMessages()
S: * 1 FETCH (UID 2 MODSEQ (1268172))
S: * 2 FETCH (UID 3 MODSEQ (1268417))
S: * 3 FETCH (UID 4 MODSEQ (1268417))
S: * 4 FETCH (UID 5 MODSEQ (1268312))
S: * 5 FETCH (UID 6 MODSEQ (1268417))
S: a005 OK Success
C: a006 FETCH 1:5 (FLAGS)                <-- fetchMessages()
S: * 1 FETCH (MODSEQ (1268172) FLAGS (NotJunk $NotJunk \Seen))
S: * 2 FETCH (MODSEQ (1268417) FLAGS (NotJunk $NotJunk \Seen))
S: * 3 FETCH (MODSEQ (1268417) FLAGS (NotJunk $NotJunk \Seen))
S: * 4 FETCH (MODSEQ (1268312) FLAGS (NotJunk $NotJunk \Seen))
S: * 5 FETCH (MODSEQ (1268417) FLAGS (NotJunk $NotJunk \Seen))
S: a006 OK Success

With the new getAndFetchMessages() method, we can now write:

vmime::shared_ptr <vmime::net::folder> f = /* ... */;

vmime::net::messageSet mset(vmime::net::messageSet::byUID(2, 6));

vmime::net::fetchAttributes attribs;

std::vector <vmime::shared_ptr <vmime::net::message> >
    msgs = f->getAndFetchMessages(mset, attribs);

// ...do something with msg[n]->getFlags()...

Here is now the dialog between the client and the server:

S: * 1 FETCH (UID 2 MODSEQ (1268172) FLAGS (NotJunk $NotJunk \Seen))
S: * 2 FETCH (UID 3 MODSEQ (1268417) FLAGS (NotJunk $NotJunk \Seen))
S: * 3 FETCH (UID 4 MODSEQ (1268417) FLAGS (NotJunk $NotJunk \Seen))
S: * 4 FETCH (UID 5 MODSEQ (1268312) FLAGS (NotJunk $NotJunk \Seen))
S: * 5 FETCH (UID 6 MODSEQ (1268417) FLAGS (NotJunk $NotJunk \Seen))
S: a006 OK Success

That is, one round-trip to the server saved. Please note that this will work with any fetch attribute, and should also work with any IMAP-compliant server!

New supported SMTP extensions

Hello VMime users,

In the last weeks, we added support for the following SMTP extensions :

  • RFC-6531: SMTP Extension for Internationalized Email (this is the continuation for the work that has been done for Internationalized Email Support)
  • RFC-3030: CHUNKING extension, for transmission of large messages
  • RFC-3030: SMTP Service Extension for Message Size Declaration

For now, few SMTP servers claim to support these features, but this is changing and we have to be ready for that. We are working on adding more features to VMime, keep on touch with us!

Internationalized Email Support

Hi there!

Today, we committed a big change into VMime codebase. We implemented preliminary support for RFC-6532 (Internationalized Email Headers), which is the (future) replacement for RFC-2047. We added support for IDN (Internationalized Domain Name) and EAI (Email Address Internationalization).

As a lot of MUAs and MSAs do not support this yet, the feature is not enabled by default (and, to be honest, we need to test this thoroughly in VMime before using it in production code). To enable it from your code, just configure the default generation context:


In the meantime, we also added message generation/parsing context and charset conversion options, to provide a better control to the user on how the messages are parsed/generated. Have a look at Doxygen-generated documentation to know more about this.

CMake and OpenSSL support!

Hi, here are some news from the front!

We migrated the build system to CMake. SCons is still usable, but should be used only for development purposes. Please note that autotools scripts should now be generated with CMake, as it has been removed from SCons script.

Thanks to the help of Mehmet Bozkurt, VMime now supports OpenSSL for SSL/TLS features, in addition to the existing support for GnuTLS.

We hope these new features will make deployment of VMime easier.

Connection time out

By popular demand, it is now possible to handle time out during connection to IMAP, POP3 and SMTP servers.

There is nothing to change in your code to enjoy this new feature, at least if you already set a time out handler on the store (vmime::net::store::setTimeoutHandler). The same time out handler is used for connection and for data exchange after the connection has been opened.

Please note: for now, this is only available in VMime SVN, revision 559, and for POSIX platforms (this feature is not yet supported on Windows).

New feature: get parsed message from store

Hi VMime users!

Let’s focus today on a new feature in VMime 0.9. Until now, when you wanted to “explore” the contents of a vmime::net::message (that is, a message hosted on a IMAP or a POP3 store), you had to extract it entirely, or to use low-level fetch() and extract() functions on the message object.

Since the current development release of May 18th, there is a new helper function that will let you access the remote message like a “normal” vmime::message, and actually download the message data only when it is required (this only works for IMAP).

// Connect to the IMAP store
vmime::ref <vmime::net::session> sess = vmime::net::session::create();

vmime::utility::url storeURL("imap://username:password@imap.example.com");

vmime::ref <vmime::net::store> store = sess->getStore(storeURL);

// Open the INBOX
vmime::ref <vmime::net::folder> folder = store->getDefaultFolder();

// Get the first message in the INBOX
vmime::ref <vmime::net::message> msg = f->getMessage(1);

// Construct the parsed message (a few data, header and structure,
// is actually downloaded from the IMAP server)
vmime::ref <vmime::message> parsedMsg = msg->getParsedMessage();

// Here, extract() will actually download message data from the server
vmime::utility::outputStreamAdapter out(std::cout);

That’s all folks! Update your source tree to the latest SVN head to enjoy this new feature.

Major bug fixes

Hello VMime users!

Thanks to László Vadócz, a possible segfault in stringUtils::countASCIIchars() has been fixed. A patch is available.

There was another major issue with body contents not generating when using streamContentHandler: EOF condition was not reset correctly when stream::reset() was called. The patch is available here.