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/home/tetron/hack/vos/apps/tutorials/vostut3server.cc

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/* Third VOS tutorial.  Local and Remote Vobjects and Messages.

   This tutorial file covers:
   - Setting up a message handler for messages
   - Accessing message fields

   This file (vostut3server.cc) is released into the public domain.  No
   restrictions are placed on its use, distribution or inclusion into
   other works.
*/

#include <vos/vos/vos.hh>

using namespace VUtil;
using namespace VOS;

#ifdef WIN32
#define sleep _sleep
#endif

// You must run this program before running vostut3client.


/* This tutorial demonstrates how to handle incoming messages.  The
   following class provides a method to be called when a message is
   received.  Message handler objects must derive from the MetaObject (discussed later)
   or VobjectExtension class.
 */
class TutorialMessageHandler : public VobjectExtension
{
private:
    vRef<Vobject> primus;
public:
    TutorialMessageHandler(Vobject* p);
    void handleSampleMessage(Message* msg);
};


int main(int argc, char** argv)
{
    std::cout << "VOS Tutorial 3 Server\n\n";

    Site localsite;
    localsite.addSiteExtension(new LocalVipSiteExtension());
    localsite.setDefaultPolicy("core:accept-all");

    vRef<Vobject> primus = localsite.createVobjectA("primus");

    /* Since primus was created on localsite, calling getSite() on
       primus just gives us back localsite.  Compare the output of
       following to the output of the same code on the client.
     */
    vRef<Site> site = primus->getSite();
    std::cout << "vostut3server: Vobject site name is: " << primus->getSiteName() << "\n";
    std::cout << "vostut3server: Vobject URL is: " << primus->getURLstr() << "\n";
    std::cout << "vostut3server: Vobject site is: " << site->getURLstr() << "\n";
    std::cout << "vostut3server: Our local site is: " << localsite.getURLstr() << "\n";

    // The difference between local and remote objects is discussed in
    // vostut3client.
    std::cout << "vostut3server: Primus is local? " << (primus->isLocal() ? "yes" : "no") << "\n";
    std::cout << "vostut3server: Primus is remote? " << (primus->isRemote() ? "yes" : "no") << "\n";

    /* Create our message handler object, passing it a pointer to
       primus.
    */
    TutorialMessageHandler* tmh = new TutorialMessageHandler(primus);

    /* Register a message handler for primus by adding the message handler
       as an extension to this vobject.  In this case, when a message
       with method "tutorial:hello" is delivered to primus, it will
       call the handleSampleMessage() method on the object "tmh" that
       we have created.
     */
    primus->getVobjectBase()->addVobjectExtension(tmh);

    /* Now idle.  When we receive a message, the message handlers will
       called in a separate thread. */
    while(true) sleep(1000);
}


TutorialMessageHandler::TutorialMessageHandler(Vobject* p)
{
    /* When assigning a bare pointer to a smart pointer, you must tell
       it whether to increment the reference count or not.  A true
       value for the second parameter means increment, a false value
       means do not increment.  Either way the reference count is
       still decremented as normal when the smart pointer goes away.
       Generally you want it to increment the count (with one common
       exception described in vostut3client.cc).
    */
    primus.assign(p, true);

    /* We only want this code to run once, so we surround it with the "init" guards.
       This adds an entry in the message handler table that indicates that message
       with the "tutorial:hello" method are passed to the TutorialMessageHandler::handleSampleMessage
       method if the target vobject has a VobjectExtension or MetaObject of type
       "TutorialMessageHandler".
     */
    static bool init = true;
    if(init) {
        init = false;
        VobjectBase::addMessageHandler("tutorial:hello", &TutorialMessageHandler::handleSampleMessage);
    }
}

void TutorialMessageHandler::handleSampleMessage(Message* msg)
{
    // First print out the message
    std::cout << "vostut3server: "
              << primus->getSiteName()
              << " received a message:\n"
              << msg->getFormattedString() << "\n";

    // Messages have a number of standard fields.  The "method"
    // field indicates the action the sender is expressing.
    std::cout << "Method is: " << msg->getMethod() << "\n";

    // Another standard field is "from".  There is of
    // course a "to" field as well :-)
    std::cout << "vostut3server: The object " << msg->getFrom() << " said hello to us!  Isn't that nice.\n";

    try {
        /* We can access a particular field using its name.  If no
           field by that name is present, then a NoSuchFieldError
           exception will be thrown.  You cannot access the fixed to,
           from, method, etc fields this way (use getTo(), getFrom(),
           getMethod() instead). */

        std::cout << "vostut3server: The word of the day is \""
             << msg->getField("word")->value << "\"\n";

    } catch(NoSuchFieldError) {
        // If we ask for a certain field on a message and it is not present,
        // this exception will be thrown
        std::cout << "vostut3server: Oops, no \"word\" field is present, no word of the day for us.\n";
    }

    std::cout << "vostut3server: The fields in this message are:\n";

    /* The fields in a message are also ordered and so we can iterate
       over them:
    */
    for(int i = 0; i < msg->numFields(); i++) {
        std::cout << " " << i << "  " << msg->getField(i)->key
                  << "=\""
                  << msg->getField(i)->value
                  << "\"\n";
    }
}