"webbrowser" --- Convenient web-browser controller
**************************************************

**Source code:** Lib/webbrowser.py

======================================================================

The "webbrowser" module provides a high-level interface to allow
displaying web-based documents to users. Under most circumstances,
simply calling the "open()" function from this module will do the
right thing.

Under Unix, graphical browsers are preferred under X11, but text-mode
browsers will be used if graphical browsers are not available or an
X11 display isn't available.  If text-mode browsers are used, the
calling process will block until the user exits the browser.

If the environment variable "BROWSER" exists, it is interpreted as the
"os.pathsep"-separated list of browsers to try ahead of the platform
defaults.  When the value of a list part contains the string "%s",
then it is interpreted as a literal browser command line to be used
with the argument URL substituted for "%s"; if the value is a single
word that refers to one of the already registered browsers this
browser is added to the front of the search list; if the part does not
contain "%s", it is simply interpreted as the name of the browser to
launch. [1]

Changed in version 3.14: The "BROWSER" variable can now also be used
to reorder the list of platform defaults. This is particularly useful
on macOS where the platform defaults do not refer to command-line
tools on "PATH".

For non-Unix platforms, or when a remote browser is available on Unix,
the controlling process will not wait for the user to finish with the
browser, but allow the remote browser to maintain its own windows on
the display.  If remote browsers are not available on Unix, the
controlling process will launch a new browser and wait.

On iOS, the "BROWSER" environment variable, as well as any arguments
controlling autoraise, browser preference, and new tab/window creation
will be ignored. Web pages will *always* be opened in the user's
preferred browser, in a new tab, with the browser being brought to the
foreground. The use of the "webbrowser" module on iOS requires the
"ctypes" module. If "ctypes" isn't available, calls to "open()" will
fail.


Command-line interface
======================

The script **webbrowser** can be used as a command-line interface for
the module. It accepts a URL as the argument. It accepts the following
optional parameters:

-n, --new-window

   Opens the URL in a new browser window, if possible.

-t, --new-tab

   Opens the URL in a new browser tab.

The options are, naturally, mutually exclusive.  Usage example:

   python -m webbrowser -t "https://www.python.org"

Availability: not WASI, not Android.

The following exception is defined:

exception webbrowser.Error

   Exception raised when a browser control error occurs.

The following functions are defined:

webbrowser.open(url, new=0, autoraise=True)

   Display *url* using the default browser. If *new* is 0, the *url*
   is opened in the same browser window if possible.  If *new* is 1, a
   new browser window is opened if possible.  If *new* is 2, a new
   browser page ("tab") is opened if possible.  If *autoraise* is
   "True", the window is raised if possible (note that under many
   window managers this will occur regardless of the setting of this
   variable).

   Returns "True" if a browser was successfully launched, "False"
   otherwise.

   Note that on some platforms, trying to open a filename using this
   function, may work and start the operating system's associated
   program.  However, this is neither supported nor portable.

   Raises an auditing event "webbrowser.open" with argument "url".

webbrowser.open_new(url)

   Open *url* in a new window of the default browser, if possible,
   otherwise, open *url* in the only browser window.

   Returns "True" if a browser was successfully launched, "False"
   otherwise.

webbrowser.open_new_tab(url)

   Open *url* in a new page ("tab") of the default browser, if
   possible, otherwise equivalent to "open_new()".

   Returns "True" if a browser was successfully launched, "False"
   otherwise.

webbrowser.get(using=None)

   Return a controller object for the browser type *using*.  If
   *using* is "None", return a controller for a default browser
   appropriate to the caller's environment.

webbrowser.register(name, constructor, instance=None, *, preferred=False)

   Register the browser type *name*.  Once a browser type is
   registered, the "get()" function can return a controller for that
   browser type.  If *instance* is not provided, or is "None",
   *constructor* will be called without parameters to create an
   instance when needed.  If *instance* is provided, *constructor*
   will never be called, and may be "None".

   Setting *preferred* to "True" makes this browser a preferred result
   for a "get()" call with no argument.  Otherwise, this entry point
   is only useful if you plan to either set the "BROWSER" variable or
   call "get()" with a nonempty argument matching the name of a
   handler you declare.

   Changed in version 3.7: *preferred* keyword-only parameter was
   added.

A number of browser types are predefined.  This table gives the type
names that may be passed to the "get()" function and the corresponding
instantiations for the controller classes, all defined in this module.

+--------------------------+-------------------------------------------+---------+
| Type Name                | Class Name                                | Notes   |
|==========================|===========================================|=========|
| "'mozilla'"              | "Mozilla('mozilla')"                      |         |
+--------------------------+-------------------------------------------+---------+
| "'firefox'"              | "Mozilla('mozilla')"                      |         |
+--------------------------+-------------------------------------------+---------+
| "'epiphany'"             | "Epiphany('epiphany')"                    |         |
+--------------------------+-------------------------------------------+---------+
| "'kfmclient'"            | "Konqueror()"                             | (1)     |
+--------------------------+-------------------------------------------+---------+
| "'konqueror'"            | "Konqueror()"                             | (1)     |
+--------------------------+-------------------------------------------+---------+
| "'kfm'"                  | "Konqueror()"                             | (1)     |
+--------------------------+-------------------------------------------+---------+
| "'opera'"                | "Opera()"                                 |         |
+--------------------------+-------------------------------------------+---------+
| "'links'"                | "GenericBrowser('links')"                 |         |
+--------------------------+-------------------------------------------+---------+
| "'elinks'"               | "Elinks('elinks')"                        |         |
+--------------------------+-------------------------------------------+---------+
| "'lynx'"                 | "GenericBrowser('lynx')"                  |         |
+--------------------------+-------------------------------------------+---------+
| "'w3m'"                  | "GenericBrowser('w3m')"                   |         |
+--------------------------+-------------------------------------------+---------+
| "'windows-default'"      | "WindowsDefault"                          | (2)     |
+--------------------------+-------------------------------------------+---------+
| "'macosx'"               | "MacOSXOSAScript('default')"              | (3)     |
+--------------------------+-------------------------------------------+---------+
| "'safari'"               | "MacOSXOSAScript('safari')"               | (3)     |
+--------------------------+-------------------------------------------+---------+
| "'google-chrome'"        | "Chrome('google-chrome')"                 |         |
+--------------------------+-------------------------------------------+---------+
| "'chrome'"               | "Chrome('chrome')"                        |         |
+--------------------------+-------------------------------------------+---------+
| "'chromium'"             | "Chromium('chromium')"                    |         |
+--------------------------+-------------------------------------------+---------+
| "'chromium-browser'"     | "Chromium('chromium-browser')"            |         |
+--------------------------+-------------------------------------------+---------+
| "'iosbrowser'"           | "IOSBrowser"                              | (4)     |
+--------------------------+-------------------------------------------+---------+

Notes:

1. "Konqueror" is the file manager for the KDE desktop environment for
   Unix, and only makes sense to use if KDE is running.  Some way of
   reliably detecting KDE would be nice; the "KDEDIR" variable is not
   sufficient.  Note also that the name "kfm" is used even when using
   the **konqueror** command with KDE 2 --- the implementation selects
   the best strategy for running Konqueror.

2. Only on Windows platforms.

3. Only on macOS.

4. Only on iOS.

Added in version 3.2: A new "MacOSXOSAScript" class has been added and
is used on Mac instead of the previous "MacOSX" class. This adds
support for opening browsers not currently set as the OS default.

Added in version 3.3: Support for Chrome/Chromium has been added.

Changed in version 3.12: Support for several obsolete browsers has
been removed. Removed browsers include Grail, Mosaic, Netscape,
Galeon, Skipstone, Iceape, and Firefox versions 35 and below.

Changed in version 3.13: Support for iOS has been added.

Here are some simple examples:

   url = 'https://docs.python.org/'

   # Open URL in a new tab, if a browser window is already open.
   webbrowser.open_new_tab(url)

   # Open URL in new window, raising the window if possible.
   webbrowser.open_new(url)


Browser controller objects
==========================

Browser controllers provide the "name" attribute, and the following
three methods which parallel module-level convenience functions:

controller.name

   System-dependent name for the browser.

controller.open(url, new=0, autoraise=True)

   Display *url* using the browser handled by this controller. If
   *new* is 1, a new browser window is opened if possible. If *new* is
   2, a new browser page ("tab") is opened if possible.

controller.open_new(url)

   Open *url* in a new window of the browser handled by this
   controller, if possible, otherwise, open *url* in the only browser
   window.  Alias "open_new()".

controller.open_new_tab(url)

   Open *url* in a new page ("tab") of the browser handled by this
   controller, if possible, otherwise equivalent to "open_new()".

-[ Footnotes ]-

[1] Executables named here without a full path will be searched in the
    directories given in the "PATH" environment variable.
