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Net::DBus::Exporter(3pm) - phpMan

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Net::DBus::Exporter(3pm)       User Contributed Perl Documentation       Net::DBus::Exporter(3pm)



NAME
       Net::DBus::Exporter - Export object methods and signals to the bus

SYNOPSIS
         # Define a new package for the object we're going
         # to export
         package Demo::HelloWorld;

         # Specify the main interface provided by our object
         use Net::DBus::Exporter qw(org.example.demo.Greeter);

         # We're going to be a DBus object
         use base qw(Net::DBus::Object);

         # Ensure only explicitly exported methods can be invoked
         dbus_strict_exports;

         # Export a 'Greeting' signal taking a stringl string parameter
         dbus_signal("Greeting", ["string"]);

         # Export 'Hello' as a method accepting a single string
         # parameter, and returning a single string value
         dbus_method("Hello", ["string"], ["string"]);

         # Export 'Goodbye' as a method accepting a single string
         # parameter, and returning a single string, but put it
         # in the 'org.exaple.demo.Farewell' interface
         dbus_method("Goodbye", ["string"], ["string"], "org.example.demo.Farewell");

DESCRIPTION
       The "Net::DBus::Exporter" module is used to export methods and signals defined in an
       object to the message bus. Since Perl is a loosely typed language it is not possible to
       automatically determine correct type information for methods to be exported.  Thus when
       sub-classing Net::DBus::Object, this package will provide the type information for methods
       and signals.

       When importing this package, an optional argument can be supplied to specify the default
       interface name to associate with methods and signals, for which an explicit interface is
       not specified.  Thus in the common case of objects only providing a single interface, this
       removes the need to repeat the interface name against each method exported.

SCALAR TYPES
       When specifying scalar data types for parameters and return values, the following string
       constants must be used to denote the data type. When values corresponding to these types
       are (un)marshalled they are represented as the Perl SCALAR data type (see perldata).

       "string"
           A UTF-8 string of characters

       "int16"
           A 16-bit signed integer

       "uint16"
           A 16-bit unsigned integer

       "int32"
           A 32-bit signed integer

       "uint32"
           A 32-bit unsigned integer

       "int64"
           A 64-bit signed integer. NB, this type is not supported by many builds of Perl on
           32-bit platforms, so if used, your data is liable to be truncated at 32-bits.

       "uint64"
           A 64-bit unsigned integer. NB, this type is not supported by many builds of Perl on
           32-bit platforms, so if used, your data is liable to be truncated at 32-bits.

       "byte"
           A single 8-bit byte

       "bool"
           A boolean value

       "double"
           An IEEE double-precision floating point

COMPOUND TYPES
       When specifying compound data types for parameters and return values, an array reference
       must be used, with the first element being the name of the compound type.

       ["array", ARRAY-TYPE]
           An array of values, whose type os "ARRAY-TYPE". The "ARRAY-TYPE" can be either a
           scalar type name, or a nested compound type. When values corresponding to the array
           type are (un)marshalled, they are represented as the Perl ARRAY data type (see
           perldata). If, for example, a method was declared to have a single parameter with the
           type, ["array", "string"], then when calling the method one would provide a array
           reference of strings:

               $object->hello(["John", "Doe"])

       ["dict", KEY-TYPE, VALUE-TYPE]
           A dictionary of values, more commonly known as a hash table. The "KEY-TYPE" is the
           name of the scalar data type used for the dictionary keys. The "VALUE-TYPE" is the
           name of the scalar, or compound data type used for the dictionary values. When values
           corresponding to the dict type are (un)marshalled, they are represented as the Perl
           HASH data type (see perldata). If, for example, a method was declared to have a single
           parameter with the type ["dict", "string", "string"], then when calling the method one
           would provide a hash reference of strings,

              $object->hello({forename => "John", surname => "Doe"});

       ["struct", VALUE-TYPE-1, VALUE-TYPE-2]
           A structure of values, best thought of as a variation on the array type where the
           elements can vary. Many languages have an explicit name associated with each value,
           but since Perl does not have a native representation of structures, they are
           represented by the LIST data type. If, for exaple, a method was declared to have a
           single parameter with the type ["struct", "string", "string"], corresponding to the C
           structure

               struct {
                 char *forename;
                 char *surname;
               } name;

           then, when calling the method one would provide an array refernce with the values
           orded to match the structure

              $object->hello(["John", "Doe"]);

MAGIC TYPES
       When specifying introspection data for an exported service, there are a couple of so
       called "magic" types. Parameters declared as magic types are not visible to clients, but
       instead their values are provided automatically by the server side bindings. One use of
       magic types is to get an extra parameter passed with the unique name of the caller
       invoking the method.

       "caller"
           The value passed in is the unique name of the caller of the method.  Unique names are
           strings automatically assigned to client connections by the bus daemon, for example
           ':1.15'

       "serial"
           The value passed in is an integer within the scope of a caller, which increments on
           every method call.

ANNOTATIONS
       When exporting methods, signals & properties, in addition to the core data typing
       information, a number of metadata annotations are possible.  These are specified by
       passing a hash reference with the desired keys as the last parameter when defining the
       export. The following annotations are currently supported

       no_return
           Indicate that this method does not return any value, and thus no reply message should
           be sent over the wire, likewise informing the clients not to expect / wait for a reply
           message

       deprecated
           Indicate that use of this method/signal/property is discouraged, and it may disappear
           altogether in a future release. Clients will typically print out a warning message
           when a deprecated method/signal/property is used.

       param_names
           An array of strings specifying names for the input parameters of the method or signal.
           If omitted, no names will be assigned.

       return_names
           An array of strings specifying names for the return parameters of the method. If
           omitted, no names will be assigned.

METHODS
       dbus_method($name, $params, $returns, [\%annotations]);
       dbus_method($name, $params, $returns, $interface, [\%annotations]);
           Exports a method called $name, having parameters whose types are defined by $params,
           and returning values whose types are defined by $returns. If the $interface parameter
           is provided, then the method is associated with that interface, otherwise the default
           interface for the calling package is used. The value for the $params parameter should
           be an array reference with each element defining the data type of a parameter to the
           method. Likewise, the $returns parameter should be an array reference with each
           element defining the data type of a return value. If it not possible to export a
           method which accepts a variable number of parameters, or returns a variable number of
           values.

       dbus_no_strict_exports();
           If a object is using the Exporter to generate DBus introspection data, the default
           behaviour is to only allow invocation of methods which have been explicitly exported.

           To allow clients to access methods which have not been explicitly exported, call
           "dbus_no_strict_exports". NB, doing this may be a security risk if you have methods
           considered to be "private" for internal use only. As such this method should not
           normally be used.  It is here only to allow switching export behaviour to match
           earlier releases.

       dbus_property($name, $type, $access, [\%attributes]);
       dbus_property($name, $type, $access, $interface, [\%attributes]);
           Exports a property called $name, whose data type is $type.  If the $interface
           parameter is provided, then the property is associated with that interface, otherwise
           the default interface for the calling package is used.

       dbus_signal($name, $params, [\%attributes]);
       dbus_signal($name, $params, $interface, [\%attributes]);
           Exports a signal called $name, having parameters whose types are defined by $params.
           If the $interface parameter is provided, then the signal is associated with that
           interface, otherwise the default interface for the calling package is used. The value
           for the $params parameter should be an array reference with each element defining the
           data type of a parameter to the signal. Signals do not have return values. It not
           possible to export a signal which has a variable number of parameters.

EXAMPLES
       No parameters, no return values
           A method which simply prints "Hello World" each time its called

              sub Hello {
                  my $self = shift;
                  print "Hello World\n";
              }

              dbus_method("Hello", [], []);

       One string parameter, returning an boolean value
           A method which accepts a process name, issues the killall command on it, and returns a
           boolean value to indicate whether it was successful.

              sub KillAll {
                  my $self = shift;
                  my $processname = shift;
                  my $ret  = system("killall $processname");
                  return $ret == 0 ? 1 : 0;
              }

              dbus_method("KillAll", ["string"], ["bool"]);

       One list of strings parameter, returning a dictionary
           A method which accepts a list of files names, stats them, and returns a dictionary
           containing the last modification times.

               sub LastModified {
                  my $self = shift;
                  my $files = shift;

                  my %mods;
                  foreach my $file (@{$files}) {
                     $mods{$file} = (stat $file)[9];
                  }
                  return \%mods;
               }

               dbus_method("LastModified", ["array", "string"], ["dict", "string", "int32"]);

       Annotating methods with metdata
           A method which is targeted for removal, and also does not return any value

               sub PlayMP3 {
                   my $self = shift;
                   my $track = shift;

                   system "mpg123 $track &";
               }

               dbus_method("PlayMP3", ["string"], [], { deprecated => 1, no_return => 1 });

           Or giving names to input parameters:

               sub PlayMP3 {
                   my $self = shift;
                   my $track = shift;

                   system "mpg123 $track &";
               }

               dbus_method("PlayMP3", ["string"], [], { param_names => ["track"] });

AUTHOR
       Daniel P. Berrange <dan AT berrange.com>

COPYRIGHT
       Copright (C) 2004-2011, Daniel Berrange.

SEE ALSO
       Net::DBus::Object, Net::DBus::Binding::Introspector



perl v5.20.0                                2014-08-15                   Net::DBus::Exporter(3pm)


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