Wt::WServer Class Reference

A class encapsulating an application server. More...

#include <Wt/WServer>

List of all members.

Public Member Functions

 WServer (const std::string &wtApplicationPath=std::string(), const std::string &wtConfigurationFile=std::string())
 Creates a new server instance.
 ~WServer ()
 Destructor.
void setServerConfiguration (int argc, char *argv[], const std::string &serverConfigurationFile=std::string())
 Configures the HTTP(S) server or FastCGI process.
void addEntryPoint (EntryPointType type, ApplicationCreator callback, const std::string &path=std::string(), const std::string &favicon=std::string())
 Binds an entry-point to a callback function to create a new application.
void addResource (WResource *resource, const std::string &path)
 Binds a resource to a fixed path.
bool start ()
 Starts the server in the background.
void stop ()
 Stops the server.
bool isRunning () const
 Returns whether the server is running.
int httpPort () const
 Returns the server http port number.

Static Public Member Functions

static int waitForShutdown (const char *restartWatchFile=0)
 Waits for a shutdown signal.
static void restart (int argc, char **argv, char **envp)
 A utility method to restart.

Related Functions

(Note that these are not member functions.)

int WRun (int argc, char **argv, ApplicationCreator createApplication=0)
 Runs the Wt application server.

Classes

class  Exception
 Server Exception class. More...


Detailed Description

A class encapsulating an application server.

This server class represents an instance of an application server.

It offers support for multiple application entry points and control over starting and stopping the server (the latter functionality is only for supported for the built-in httpd). This may be used as an alternative to using WRun() when you wish to support multiple application entry points, or for integrating a Wt (stand-alone httpd) server application into an existing application, when you want to and start and stop the server as appropriate.

As an example usage, consider the implementation of WRun(), which starts the server until a Ctrl-C is pressed or a termination signal has been received, or a restart is indicated using SIGHUP or a changed binary (argv[0]):

int WRun(int argc, char *argv[], ApplicationCreator createApplication)
{
  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)
    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(WServer::Application, createApplication);
    if (server.start()) {
      int sig = WServer::waitForShutdown(argv[0]);

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

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

Note:
Currently, only a single server instance may be created. We plan to remove this limiation in the future.

Constructor & Destructor Documentation

Wt::WServer::WServer ( const std::string &  wtApplicationPath = std::string(),
const std::string &  wtConfigurationFile = std::string() 
)

Creates a new server instance.

The wtApplicationPath is used to match specific application-settings in the Wt configuration file. If no specific match could be found, the general settings are used (corresponding to the '*' selector).

The Wt application configuration is read from the wtConfigurationFile. If empty, this defaults to the value configured at build time.

For more information on configuring Wt applications, see Configuration.

Exceptions:
Exception : indicates a configuration problem.
See also:
setServerConfiguration()

Wt::WServer::~WServer (  ) 

Destructor.

If the server was still running, it is stopped first by calling stop(). It is probably safer to call stop() first yourself, since this allows exceptions to be caught.

See also:
isRunning(), stop()


Member Function Documentation

void Wt::WServer::setServerConfiguration ( int  argc,
char *  argv[],
const std::string &  serverConfigurationFile = std::string() 
)

Configures the HTTP(S) server or FastCGI process.

Configures the HTTP(S) server using command-line arguments, a configuration file, or both. The valid options are described in Built-in httpd configuration.

The applications themselves are configured using the configuration file passed to the constructor.

The server configuration must be set before any other functionality can be used.

In case of FastCGI deployment, the serverConfigurationFile argument is ignored, and depending on the command-line arguments, this process may become a FastCGI protocol relay process which never returning from this call but directs the FastCGI stream to the correct session, rather than a Wt application server.

Exceptions:
Exception : indicates a configuration problem.

void Wt::WServer::addEntryPoint ( EntryPointType  type,
ApplicationCreator  callback,
const std::string &  path = std::string(),
const std::string &  favicon = std::string() 
)

Binds an entry-point to a callback function to create a new application.

The path is the local URL at which the application is deployed: when a user visits this URL, the callback will be called to create a new application. If empty, the URL is inferred from the server configuration's deploy-path (see also Built-in httpd configuration).

The path must start with a '/'.

The optional favicon is a URL path (which should not contain the host part!) to a favicon, which is the icon displayed in the browser for your application. Alternatively, you may specify a favicon using the "favicon" property in the configuration file (see als Application settings (wt_config.xml)").

void Wt::WServer::addResource ( WResource resource,
const std::string &  path 
)

Binds a resource to a fixed path.

Resources may either be private to a single session or public. Use this method to add a public resource with a fixed path.

bool Wt::WServer::start (  ) 

Starts the server in the background.

Returns whether the server could be successfully started.

Exceptions:
Exception : indicates a problem starting the server.
See also:
isRunning(), stop()

void Wt::WServer::stop (  ) 

Stops the server.

All active application sessions are terminated cleanly, and the HTTP(S) server is shut down.

Exceptions:
Exception : indicates a problem while stopping the server.
See also:
isRunning(), start()

static int Wt::WServer::waitForShutdown ( const char *  restartWatchFile = 0  )  [static]

Waits for a shutdown signal.

This static method blocks the current thread, waiting for a shutdown signal. The implementation and details are platform dependent, but this is usually Ctrl-C (SIGINT), SIGKILL, or SIGHUP.

This method is convenient if you want to customize how the server is started (by instantiating a WServer object yourself, instead of using Wt::Wrun()), but still want to use Wt as a standalone server that cleanly terminates on interruption.

The optional restartWatchFile parameter can be used to let the server watch for changes to a particular file (usually the binary itself, argv[0]) which it will also interpret as SIGHUP. This may be convenient to start the new binary after cleanly shutting down, using restart(). (Experimental, UNIX only)

static void Wt::WServer::restart ( int  argc,
char **  argv,
char **  envp 
) [static]

A utility method to restart.

This will result the application with the new image (argv[0]), effectively loading a newly deployed version. (Experimental, UNIX only)

bool Wt::WServer::isRunning (  )  const

Returns whether the server is running.

See also:
start(), stop()

int Wt::WServer::httpPort (  )  const

Returns the server http port number.

Returns -1 if the port is not known (i.e. because the connector is not aware of how the http server is configured).


Friends And Related Function Documentation

int WRun ( int  argc,
char **  argv,
ApplicationCreator  createApplication = 0 
) [related]

Runs the Wt application server.

This function runs the application server, and should be called only once (e.g. from within your main function).

The createApplication argument is a function pointer to create new application instances for each new user surfing to your application.

When using the built-in httpd, the implementation listens for POSIX termination signals (or console CTRL-C) event. You can use the WServer class for more flexible control on starting and stopping the server.

See also:
WApplication


Generated on Fri Mar 26 17:12:07 2010 for Wt by doxygen 1.5.6