GSocketConnectable

GSocketConnectable — Interface for potential socket endpoints

Synopsis

                    GSocketConnectable;
                    GSocketConnectableIface;
GSocketAddressEnumerator * g_socket_connectable_enumerate
                                                        (GSocketConnectable *connectable);
GSocketAddressEnumerator * g_socket_connectable_proxy_enumerate
                                                        (GSocketConnectable *connectable);

                    GSocketAddressEnumerator;
GSocketAddress *    g_socket_address_enumerator_next    (GSocketAddressEnumerator *enumerator,
                                                         GCancellable *cancellable,
                                                         GError **error);
void                g_socket_address_enumerator_next_async
                                                        (GSocketAddressEnumerator *enumerator,
                                                         GCancellable *cancellable,
                                                         GAsyncReadyCallback callback,
                                                         gpointer user_data);
GSocketAddress *    g_socket_address_enumerator_next_finish
                                                        (GSocketAddressEnumerator *enumerator,
                                                         GAsyncResult *result,
                                                         GError **error);

                    GProxyAddressEnumerator;

Object Hierarchy

  GInterface
   +----GSocketConnectable

  GObject
   +----GSocketAddressEnumerator
         +----GProxyAddressEnumerator

  GObject
   +----GSocketAddressEnumerator
         +----GProxyAddressEnumerator

Prerequisites

GSocketConnectable requires GObject.

Known Implementations

GSocketConnectable is implemented by GInetSocketAddress, GNetworkAddress, GNetworkService, GProxyAddress, GSocketAddress and GUnixSocketAddress.

Properties

  "connectable"              GSocketConnectable*   : Read / Write / Construct Only
  "uri"                      gchar*                : Read / Write / Construct Only

Description

Objects that describe one or more potential socket endpoints implement GSocketConnectable. Callers can then use g_socket_connectable_enumerate() to get a GSocketAddressEnumerator to try out each socket address in turn until one succeeds, as shown in the sample code below. 

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MyConnectionType *
connect_to_host (const char    *hostname,
                 guint16        port,
                 GCancellable  *cancellable,
                 GError       **error)
{
  MyConnection *conn = NULL;
  GSocketConnectable *addr;
  GSocketAddressEnumerator *enumerator;
  GSocketAddress *sockaddr;
  GError *conn_error = NULL;

  addr = g_network_address_new ("www.gnome.org", 80);
  enumerator = g_socket_connectable_enumerate (addr);
  g_object_unref (addr);

  /* Try each sockaddr until we succeed. Record the first
   * connection error, but not any further ones (since they'll probably
   * be basically the same as the first).
   */
  while (!conn && (sockaddr = g_socket_address_enumerator_next (enumerator, cancellable, error))
    {
      conn = connect_to_sockaddr (sockaddr, conn_error ? NULL : &conn_error);
      g_object_unref (sockaddr);
    }
  g_object_unref (enumerator);

  if (conn)
    {
      if (conn_error)
        {
          /* We couldn't connect to the first address, but we succeeded
           * in connecting to a later address.
           */
          g_error_free (conn_error);
        }
      return conn;
    }
  else if (error)
    {
      /* Either the initial lookup failed, or else the caller
       * cancelled us.
       */
      if (conn_error)
        g_error_free (conn_error);
      return NULL;
    }
  else
    {
      g_error_propagate (error, conn_error);
      return NULL;
    }
}

Details

GSocketConnectable

typedef struct _GSocketConnectable GSocketConnectable;

Interface for objects that contain or generate GSocketAddresses.

GSocketConnectableIface

typedef struct {
  GTypeInterface g_iface;

  /* Virtual Table */

  GSocketAddressEnumerator * (* enumerate)       (GSocketConnectable *connectable);

  GSocketAddressEnumerator * (* proxy_enumerate) (GSocketConnectable *connectable);
} GSocketConnectableIface;

Provides an interface for returning a GSocketAddressEnumerator and GProxyAddressEnumerator

GTypeInterface g_iface;

 The parent interface.

enumerate ()

 Creates a GSocketAddressEnumerator

proxy_enumerate ()

 Creates a GProxyAddressEnumerator

g_socket_connectable_enumerate ()

GSocketAddressEnumerator * g_socket_connectable_enumerate
                                                        (GSocketConnectable *connectable);

Creates a GSocketAddressEnumerator for connectable.

connectable :

 a GSocketConnectable

Returns :

 a new GSocketAddressEnumerator.

Since 2.22

g_socket_connectable_proxy_enumerate ()

GSocketAddressEnumerator * g_socket_connectable_proxy_enumerate
                                                        (GSocketConnectable *connectable);

Creates a GSocketAddressEnumerator for connectable that will return GProxyAddresses for addresses that you must connect to via a proxy.

If connectable does not implement g_socket_connectable_proxy_enumerate(), this will fall back to calling g_socket_connectable_enumerate().

connectable :

 a GSocketConnectable

Returns :

 a new GSocketAddressEnumerator.

Since 2.26

GSocketAddressEnumerator

typedef struct _GSocketAddressEnumerator GSocketAddressEnumerator;

Enumerator type for objects that contain or generate GSocketAddresses.

g_socket_address_enumerator_next ()

GSocketAddress *    g_socket_address_enumerator_next    (GSocketAddressEnumerator *enumerator,
                                                         GCancellable *cancellable,
                                                         GError **error);

Retrieves the next GSocketAddress from enumerator. Note that this may block for some amount of time. (Eg, a GNetworkAddress may need to do a DNS lookup before it can return an address.) Use g_socket_address_enumerator_next_async() if you need to avoid blocking.

If enumerator is expected to yield addresses, but for some reason is unable to (eg, because of a DNS error), then the first call to g_socket_address_enumerator_next() will return an appropriate error in *error. However, if the first call to g_socket_address_enumerator_next() succeeds, then any further internal errors (other than cancellable being triggered) will be ignored.

enumerator :

 a GSocketAddressEnumerator

cancellable :

 optional GCancellable object, NULL to ignore.

error :

 a GError.

Returns :

 a GSocketAddress (owned by the caller), or NULL on error (in which case *error will be set) or if there are no more addresses.

g_socket_address_enumerator_next_async ()

void                g_socket_address_enumerator_next_async
                                                        (GSocketAddressEnumerator *enumerator,
                                                         GCancellable *cancellable,
                                                         GAsyncReadyCallback callback,
                                                         gpointer user_data);

Asynchronously retrieves the next GSocketAddress from enumerator and then calls callback, which must call g_socket_address_enumerator_next_finish() to get the result.

enumerator :

 a GSocketAddressEnumerator

cancellable :

 optional GCancellable object, NULL to ignore.

callback :

 a GAsyncReadyCallback to call when the request is satisfied

user_data :

 the data to pass to callback function

g_socket_address_enumerator_next_finish ()

GSocketAddress *    g_socket_address_enumerator_next_finish
                                                        (GSocketAddressEnumerator *enumerator,
                                                         GAsyncResult *result,
                                                         GError **error);

Retrieves the result of a completed call to g_socket_address_enumerator_next_async(). See g_socket_address_enumerator_next() for more information about error handling.

enumerator :

 a GSocketAddressEnumerator

result :

 a GAsyncResult

error :

 a GError

Returns :

 a GSocketAddress (owned by the caller), or NULL on error (in which case *error will be set) or if there are no more addresses.

GProxyAddressEnumerator

typedef struct _GProxyAddressEnumerator GProxyAddressEnumerator;

A subclass of GSocketAddressEnumerator that takes another address enumerator and wraps its results in GProxyAddresses as directed by the default GProxyResolver.

Property Details

The "connectable" property

  "connectable"              GSocketConnectable*   : Read / Write / Construct Only

The connectable being enumerated.

The "uri" property

  "uri"                      gchar*                : Read / Write / Construct Only

The destination URI, use none:// for generic socket.

Default value: NULL

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