Gio.ApplicationCommandLine

g GObject.Object GObject.Object Gio.ApplicationCommandLine Gio.ApplicationCommandLine GObject.Object->Gio.ApplicationCommandLine

Subclasses:None

Methods

Inherited:GObject.Object (37)
Structs:GObject.ObjectClass (5)
  create_file_for_arg (arg)
  get_arguments ()
  get_cwd ()
  get_environ ()
  get_exit_status ()
  get_is_remote ()
  get_options_dict ()
  get_platform_data ()
  get_stdin ()
  getenv (name)
  set_exit_status (exit_status)

Virtual Methods

Inherited:GObject.Object (7)
  do_get_stdin ()
  do_print_literal (message)
  do_printerr_literal (message)

Properties

Name Type Flags Short Description
arguments GLib.Variant w/co The commandline that caused this ::command-line signal emission
is-remote bool r True if this is a remote commandline
options GLib.Variant w/co The options sent along with the commandline
platform-data GLib.Variant w/co Platform-specific data for the commandline

Signals

Inherited:GObject.Object (1)

Fields

Inherited:GObject.Object (1)
Name Type Access Description
parent_instance GObject.Object r  

Class Details

class Gio.ApplicationCommandLine(**kwargs)
Bases:GObject.Object
Abstract:No
Structure:Gio.ApplicationCommandLineClass

Gio.ApplicationCommandLine represents a command-line invocation of an application. It is created by Gio.Application and emitted in the Gio.Application ::command-line signal and virtual function.

The class contains the list of arguments that the program was invoked with. It is also possible to query if the commandline invocation was local (ie: the current process is running in direct response to the invocation) or remote (ie: some other process forwarded the commandline to this process).

The Gio.ApplicationCommandLine object can provide the argc and argv parameters for use with the GLib.OptionContext command-line parsing API, with the Gio.ApplicationCommandLine.get_arguments() function. See ‘gapplication-example-cmdline3.c [gapplication-example-cmdline3]’ for an example.

The exit status of the originally-invoked process may be set and messages can be printed to stdout or stderr of that process. The lifecycle of the originally-invoked process is tied to the lifecycle of this object (ie: the process exits when the last reference is dropped).

The main use for Gio.ApplicationCommandLine (and the Gio.Application ::command-line signal) is ‘Emacs server’ like use cases: You can set the EDITOR environment variable to have e.g. git use your favourite editor to edit commit messages, and if you already have an instance of the editor running, the editing will happen in the running instance, instead of opening a new one. An important aspect of this use case is that the process that gets started by git does not return until the editing is done.

Normally, the commandline is completely handled in the Gio.Application ::command-line handler. The launching instance exits once the signal handler in the primary instance has returned, and the return value of the signal handler becomes the exit status of the launching instance.

static int
command_line (GApplication            *application,
              GApplicationCommandLine *cmdline)
{
  gchar **argv;
  gint argc;
  gint i;

  argv = g_application_command_line_get_arguments (cmdline, &argc);

  g_application_command_line_print (cmdline,
                                    "This text is written back\n"
                                    "to stdout of the caller\n");

  for (i = 0; i < argc; i++)
    g_print ("argument %d: %s\n", i, argv[i]);

  g_strfreev (argv);

  return 0;
}

The complete example can be found here: gapplication-example-cmdline.c

In more complicated cases, the handling of the comandline can be split between the launcher and the primary instance.

static gboolean
 test_local_cmdline (GApplication   *application,
                     gchar        ***arguments,
                     gint           *exit_status)
{
  gint i, j;
  gchar **argv;

  argv = *arguments;

  i = 1;
  while (argv[i])
    {
      if (g_str_has_prefix (argv[i], "--local-"))
        {
          g_print ("handling argument %s locally\n", argv[i]);
          g_free (argv[i]);
          for (j = i; argv[j]; j++)
            argv[j] = argv[j + 1];
        }
      else
        {
          g_print ("not handling argument %s locally\n", argv[i]);
          i++;
        }
    }

  *exit_status = 0;

  return FALSE;
}

static void
test_application_class_init (TestApplicationClass *class)
{
  G_APPLICATION_CLASS (class)->local_command_line = test_local_cmdline;

  ...
}

In this example of split commandline handling, options that start with --local- are handled locally, all other options are passed to the Gio.Application ::command-line handler which runs in the primary instance.

The complete example can be found here: gapplication-example-cmdline2.c

If handling the commandline requires a lot of work, it may be better to defer it.

static gboolean
my_cmdline_handler (gpointer data)
{
  GApplicationCommandLine *cmdline = data;

  // do the heavy lifting in an idle

  g_application_command_line_set_exit_status (cmdline, 0);
  g_object_unref (cmdline); // this releases the application

  return G_SOURCE_REMOVE;
}

static int
command_line (GApplication            *application,
              GApplicationCommandLine *cmdline)
{
  // keep the application running until we are done with this commandline
  g_application_hold (application);

  g_object_set_data_full (G_OBJECT (cmdline),
                          "application", application,
                          (GDestroyNotify)g_application_release);

  g_object_ref (cmdline);
  g_idle_add (my_cmdline_handler, cmdline);

  return 0;
}

In this example the commandline is not completely handled before the Gio.Application ::command-line handler returns. Instead, we keep a reference to the Gio.ApplicationCommandLine object and handle it later (in this example, in an idle). Note that it is necessary to hold the application until you are done with the commandline.

The complete example can be found here: gapplication-example-cmdline3.c

create_file_for_arg(arg)[source]
Parameters:arg (str) – an argument from self
Returns:a new Gio.File
Return type:Gio.File

Creates a Gio.File corresponding to a filename that was given as part of the invocation of self.

This differs from Gio.File.new_for_commandline_arg() in that it resolves relative pathnames using the current working directory of the invoking process rather than the local process.

New in version 2.36.

get_arguments()[source]
Returns:the string array containing the arguments (the argv)
Return type:[str]

Gets the list of arguments that was passed on the command line.

The strings in the array may contain non-UTF-8 data on UNIX (such as filenames or arguments given in the system locale) but are always in UTF-8 on Windows.

If you wish to use the return value with GLib.OptionContext, you must use GLib.OptionContext.parse_strv().

The return value is None-terminated and should be freed using GLib.strfreev().

New in version 2.28.

get_cwd()[source]
Returns:the current directory, or None
Return type:str or None

Gets the working directory of the command line invocation. The string may contain non-utf8 data.

It is possible that the remote application did not send a working directory, so this may be None.

The return value should not be modified or freed and is valid for as long as self exists.

New in version 2.28.

get_environ()[source]
Returns:the environment strings, or None if they were not sent
Return type:[str]

Gets the contents of the ‘environ’ variable of the command line invocation, as would be returned by GLib.get_environ(), ie as a None-terminated list of strings in the form ‘NAME=VALUE’. The strings may contain non-utf8 data.

The remote application usually does not send an environment. Use Gio.ApplicationFlags.SEND_ENVIRONMENT to affect that. Even with this flag set it is possible that the environment is still not available (due to invocation messages from other applications).

The return value should not be modified or freed and is valid for as long as self exists.

See Gio.ApplicationCommandLine.getenv() if you are only interested in the value of a single environment variable.

New in version 2.28.

get_exit_status()[source]
Returns:the exit status
Return type:int

Gets the exit status of self. See Gio.ApplicationCommandLine.set_exit_status() for more information.

New in version 2.28.

get_is_remote()[source]
Returns:True if the invocation was remote
Return type:bool

Determines if self represents a remote invocation.

New in version 2.28.

get_options_dict()[source]
Returns:a GLib.VariantDict with the options
Return type:GLib.VariantDict

Gets the options there were passed to g_application_command_line().

If you did not override local_command_line() then these are the same options that were parsed according to the GLib.OptionEntrys added to the application with Gio.Application.add_main_option_entries() and possibly modified from your Gio.Application ::handle-local-options handler.

If no options were sent then an empty dictionary is returned so that you don’t need to check for None.

New in version 2.40.

get_platform_data()[source]
Returns:the platform data, or None
Return type:GLib.Variant or None

Gets the platform data associated with the invocation of self.

This is a GLib.Variant dictionary containing information about the context in which the invocation occurred. It typically contains information like the current working directory and the startup notification ID.

For local invocation, it will be None.

New in version 2.28.

get_stdin()[source]
Returns:a Gio.InputStream for stdin
Return type:Gio.InputStream

Gets the stdin of the invoking process.

The Gio.InputStream can be used to read data passed to the standard input of the invoking process. This doesn’t work on all platforms. Presently, it is only available on UNIX when using a DBus daemon capable of passing file descriptors. If stdin is not available then None will be returned. In the future, support may be expanded to other platforms.

You must only call this function once per commandline invocation.

New in version 2.34.

getenv(name)[source]
Parameters:name (str) – the environment variable to get
Returns:the value of the variable, or None if unset or unsent
Return type:str

Gets the value of a particular environment variable of the command line invocation, as would be returned by GLib.getenv(). The strings may contain non-utf8 data.

The remote application usually does not send an environment. Use Gio.ApplicationFlags.SEND_ENVIRONMENT to affect that. Even with this flag set it is possible that the environment is still not available (due to invocation messages from other applications).

The return value should not be modified or freed and is valid for as long as self exists.

New in version 2.28.

set_exit_status(exit_status)[source]
Parameters:exit_status (int) – the exit status

Sets the exit status that will be used when the invoking process exits.

The return value of the Gio.Application ::command-line signal is passed to this function when the handler returns. This is the usual way of setting the exit status.

In the event that you want the remote invocation to continue running and want to decide on the exit status in the future, you can use this call. For the case of a remote invocation, the remote process will typically exit when the last reference is dropped on self. The exit status of the remote process will be equal to the last value that was set with this function.

In the case that the commandline invocation is local, the situation is slightly more complicated. If the commandline invocation results in the mainloop running (ie: because the use-count of the application increased to a non-zero value) then the application is considered to have been ‘successful’ in a certain sense, and the exit status is always zero. If the application use count is zero, though, the exit status of the local Gio.ApplicationCommandLine is used.

New in version 2.28.

do_get_stdin() virtual
Returns:a Gio.InputStream for stdin
Return type:Gio.InputStream

Gets the stdin of the invoking process.

The Gio.InputStream can be used to read data passed to the standard input of the invoking process. This doesn’t work on all platforms. Presently, it is only available on UNIX when using a DBus daemon capable of passing file descriptors. If stdin is not available then None will be returned. In the future, support may be expanded to other platforms.

You must only call this function once per commandline invocation.

New in version 2.34.

do_print_literal(message) virtual
Parameters:message (str) –
do_printerr_literal(message) virtual
Parameters:message (str) –

Property Details

Gio.ApplicationCommandLine.props.arguments
Name:arguments
Type:GLib.Variant
Default Value:None
Flags:WRITABLE, CONSTRUCT_ONLY

The commandline that caused this ::command-line signal emission

Gio.ApplicationCommandLine.props.is_remote
Name:is-remote
Type:bool
Default Value:False
Flags:READABLE

True if this is a remote commandline

Gio.ApplicationCommandLine.props.options
Name:options
Type:GLib.Variant
Default Value:None
Flags:WRITABLE, CONSTRUCT_ONLY

The options sent along with the commandline

Gio.ApplicationCommandLine.props.platform_data
Name:platform-data
Type:GLib.Variant
Default Value:None
Flags:WRITABLE, CONSTRUCT_ONLY

Platform-specific data for the commandline