## gupnp-binding-tool

gupnp-binding-tool — creates C convenience wrappers for UPnP services

## Synopsis

`gupnp-binding-tool` [--prefix {PREFIX}] [--mode {client|server}] {SCPD file}

## Description

gupnp-binding-tool takes a SCPD file and generates convenience C functions which call the actual GUPnP functions. The client-side bindings can be seen as a service-specific version of the GUPnPServiceProxy API and the service-side bindings are the same for GUPnPService.

These generated functions are less verbose and also safer as function call parameters are correctly typed. Action, variable and query names are easier to get correct with bindings (or at least the errors will be compile-time errors instead of run-time), and are also available in editor autocompletion.

## Client side bindings

As an example, this action:

    <action>
      <name>DeletePortMapping</name>
      <argumentList>
        <argument>
          <name>NewRemoteHost</name>
          <direction>in</direction>
          <relatedStateVariable>RemoteHost</relatedStateVariable>
        </argument>
        <argument>
          <name>NewExternalPort</name>
          <direction>in</direction>
          <relatedStateVariable>ExternalPort</relatedStateVariable>
        </argument>
        <argument>
          <name>NewProtocol</name>
          <direction>in</direction>
          <relatedStateVariable>PortMappingProtocol</relatedStateVariable>
        </argument>
      </argumentList>
    </action>

Will generate the following synchronous client-side (control point) function:

    static inline gboolean
    igd_delete_port_mapping (GUPnPServiceProxy *proxy,
                             const gchar *in_new_remote_host,
                             const guint in_new_external_port,
                             const gchar *in_new_protocol,
                             GError **error);

As can be seen, the arguments have the correct types and are prefixed with the argument direction.

gupnp-binding-tool generates both synchronous and asynchronous wrappers. The `igd_delete_port_mapping` example above is the synchronous form, the asynchronous form is as follows:

    typedef void (*igd_delete_port_mapping_reply) (GUPnPServiceProxy *proxy,
                                                   GError *error,
                                                   gpointer userdata);

    static inline GUPnPServiceProxyAction *
    igd_delete_port_mapping_async (GUPnPServiceProxy *proxy,
                                   const gchar *in_new_remote_host,
                                   const guint in_new_external_port,
                                   const gchar *in_new_protocol,
                                   igd_delete_port_mapping_reply callback,
                                   gpointer userdata);

The asynchronous form (implemented using `gupnp_service_proxy_begin_action()` and `gupnp_service_proxy_end_action()`) will return without blocking and later invoke the callback from the main loop when the reply is received.

The tool also creates bindings for state variable notifications. This state variable definition:

    <stateVariable sendEvents="yes">
      <name>ExternalIPAddress</name>
      <dataType>string</dataType>
    </stateVariable>

will create this client binding that can be used to get notifications on "ExternalIPAddress" changes:

    typedef void
    (*igd_external_ip_address_changed_callback) (GUPnPServiceProxy *proxy,
                                                 const gchar *external_ip_address,
                                                 gpointer userdata);

    static inline gboolean
    igd_external_ip_address_add_notify (GUPnPServiceProxy *proxy,
                                        igd_external_ip_address_changed_callback callback,
                                        gpointer userdata);

All of the examples were produced with `gupnp-binding-tool --prefix igd --mode client WANIPConnection.xml`.

## Server side bindings

The corresponding server bindings for the same UPnP action (DeletePortMapping) look like this:

    void
    igd_delete_port_mapping_action_get (GUPnPServiceAction *action,
                                        gchar **in_new_remote_host,
                                        guint *in_new_external_port,
                                        gchar **in_new_protocol);

    gulong
    igd_delete_port_mapping_action_connect (GUPnPService *service,
                                            GCallback callback,
                                            gpointer userdata);

The generated *_action_connect() function can be used to connect the action handler. The *_action_get() and *_action_set() functions can then be used inside the action handler to get/set action variables. If notified variables are modified, the *_variable_notify() should be used to send the notifications (see below).

    typedef gchar *(*igd_external_ip_address_query_callback) (GUPnPService *service,
                                                              gpointer userdata);

    gulong
    igd_external_ip_address_query_connect (GUPnPService *service,
                                           igd_external_ip_address_query_callback callback,
                                           gpointer userdata);
    void
    igd_external_ip_address_variable_notify (GUPnPService *service,
                                             const gchar *external_ip_address);

The *_query_connect() function can be used to connect the service-specific query handler. The return value of the handler is the returned state variable value.

All of the examples were produced with `gupnp-binding-tool --prefix igd --mode server WANIPConnection.xml`.