Can multiple WT applications run on same port?

Question

Update 1: I have recently found out that WT communicates using TCP (HTTP), if that helps anyone.

The title says it all, is it possible to run 2 different WT applications or projects on the same port? I know WT has come control over how the application is hosted with its start up parameters as follows. I am using Visual Studio 2010 and the parameters below are entered in the debugging->command arguments box as follows:

--http-address=0.0.0.0 --http-port=8080 --deploy-path=/hello --docroot=.

The above parameters will require that the user opens a web page at

http://127.0.0.1:8080/hello

So I though, hey what if I host another project with the below parameters

--http-address=0.0.0.0 --http-port=8080 --deploy-path=/world --docroot=.

so then I would need to connect to

http://127.0.0.1:8080/world

The above actually does not work, it only hosts the first application that connects, and the second will not connect until the first shuts down. So this brings me here. Are there any other ways to run multiple WT applications on the same port?

Thank you in advance for any help!

Answer 1

Yes, you can achieve that but you will need to create your own WRun and use addEntryPoint. This is actually mentioned in the tutorial and goes as follows:

Inside WRun()

WRun() is actually a convenience function which creates and configures a WServer instance. If you want more control, for example if you have multiple “entry points”, or want to control the server starting and stopping, you can use the WServer API directly instead.

Here you have an example, both applications are the Hello World application, but notice that they have different titles and different messages on the buttons and when you press them. You can find another implementation of WRun on src/http/Serve.C and src/Wt/WServer.

two_helloworlds.cc

#include <Wt/WApplication>
#include <Wt/WBreak>
#include <Wt/WContainerWidget>
#include <Wt/WLineEdit>
#include <Wt/WPushButton>
#include <Wt/WText>
#include <Wt/WException>
#include <Wt/WLogger>
#include <Wt/WServer>

class HelloApplication : public Wt::WApplication
{
public:
    HelloApplication(const Wt::WEnvironment& env, const std::string& title);

private:
    Wt::WLineEdit *nameEdit_;
    Wt::WText *greeting_;

    void greet();
};

HelloApplication::HelloApplication(const Wt::WEnvironment& env, const std::string& title)
    : Wt::WApplication(env)
{
    setTitle(title);

    root()->addWidget(new Wt::WText("Your name, please ? "));
    nameEdit_ = new Wt::WLineEdit(root());
    Wt::WPushButton *button = new Wt::WPushButton("Greet me.", root());
    root()->addWidget(new Wt::WBreak());
    greeting_ = new Wt::WText(root());
    button->clicked().connect(this, &HelloApplication::greet);
}

void HelloApplication::greet()
{    greeting_->setText("Hello there, " + nameEdit_->text());
}
class GoodbyeApplication : public Wt::WApplication{
public:
    GoodbyeApplication(const Wt::WEnvironment& env, const std::string& title);

private:    Wt::WLineEdit *nameEdit_;
    Wt::WText *greeting_;


    void greet();
};

GoodbyeApplication::GoodbyeApplication(const Wt::WEnvironment& env, const std::string& title)
    : Wt::WApplication(env)
{
    setTitle(title);

    root()->addWidget(new Wt::WText("Your name, please ? "));
    nameEdit_ = new Wt::WLineEdit(root());
    Wt::WPushButton *button = new Wt::WPushButton("Say goodbye.", root());
    root()->addWidget(new Wt::WBreak());
    greeting_ = new Wt::WText(root());
    button->clicked().connect(this, &GoodbyeApplication::greet);
}

void GoodbyeApplication::greet()
{
    greeting_->setText("Goodbye, " + nameEdit_->text());
}

Wt::WApplication *createApplication(const Wt::WEnvironment& env)
{
    return new HelloApplication(env, "First app");
}

Wt::WApplication *createSecondApplication(const Wt::WEnvironment& env)
{
    return new GoodbyeApplication(env, "Second app");
}

int YourWRun(int argc, char *argv[], Wt::ApplicationCreator createApplication, Wt::ApplicationCreator createSecondApplication)
{
  try {
    // use argv[0] as the application name to match a suitable entry
    // in the Wt configuration file, and use the default configuration
    // file (which defaults to /etc/wt/wt_config.xml unless the environment
    // variable WT_CONFIG_XML is set)
    Wt::WServer server(argv[0],"");

    // WTHTTP_CONFIGURATION is e.g. "/etc/wt/wthttpd"
    server.setServerConfiguration(argc, argv, WTHTTP_CONFIGURATION);

    // add a single entry point, at the default location (as determined
    // by the server configuration's deploy-path)
    server.addEntryPoint(Wt::Application, createApplication);
    server.addEntryPoint(Wt::Application, createSecondApplication,"/second");
    if (server.start()) {
      int sig = Wt::WServer::waitForShutdown(argv[0]);

      std::cerr << "Shutdown (signal = " << sig << ")" << std::endl;
      server.stop();

      /*
      if (sig == SIGHUP)
        WServer::restart(argc, argv, environ);
      */
      }
  } catch (Wt::WServer::Exception& e) {
    std::cerr << e.what() << "\n";
    return 1;
  } catch (std::exception& e) {
    std::cerr << "exception: " << e.what() << "\n";
    return 1;
  }
}

int main(int argc, char **argv)
{
    return YourWRun(argc, argv, &createApplication, &createSecondApplication);
}

Compile it with

g++ -g -o two_helloworlds two_helloworlds.cc -I/usr/local/include -L/usr/local/lib -lwthttp -lwt -lboost_random -lboost_regex -lboost_signals -lboost_system -lboost_thread -lboost_filesystem -lboost_program_options -lboost_date_time

and execute with

./two_helloworlds --docroot . --http-address 0.0.0.0 --http-port 8080

on localhost:8080 you will access one of the applications and on localhost:8080/second you will access the other.