cpython/Lib/webbrowser.py
Aarni Koskela 0b6acfee04
gh-123494: Improve documentation for `webbrowser` return types (#123495)
Document the return value for ``webbrowser.open*()``.
2024-09-01 06:17:03 +01:00

710 lines
24 KiB
Python

"""Interfaces for launching and remotely controlling web browsers."""
# Maintained by Georg Brandl.
import os
import shlex
import shutil
import sys
import subprocess
import threading
__all__ = ["Error", "open", "open_new", "open_new_tab", "get", "register"]
class Error(Exception):
pass
_lock = threading.RLock()
_browsers = {} # Dictionary of available browser controllers
_tryorder = None # Preference order of available browsers
_os_preferred_browser = None # The preferred browser
def register(name, klass, instance=None, *, preferred=False):
"""Register a browser connector."""
with _lock:
if _tryorder is None:
register_standard_browsers()
_browsers[name.lower()] = [klass, instance]
# Preferred browsers go to the front of the list.
# Need to match to the default browser returned by xdg-settings, which
# may be of the form e.g. "firefox.desktop".
if preferred or (_os_preferred_browser and f'{name}.desktop' == _os_preferred_browser):
_tryorder.insert(0, name)
else:
_tryorder.append(name)
def get(using=None):
"""Return a browser launcher instance appropriate for the environment."""
if _tryorder is None:
with _lock:
if _tryorder is None:
register_standard_browsers()
if using is not None:
alternatives = [using]
else:
alternatives = _tryorder
for browser in alternatives:
if '%s' in browser:
# User gave us a command line, split it into name and args
browser = shlex.split(browser)
if browser[-1] == '&':
return BackgroundBrowser(browser[:-1])
else:
return GenericBrowser(browser)
else:
# User gave us a browser name or path.
try:
command = _browsers[browser.lower()]
except KeyError:
command = _synthesize(browser)
if command[1] is not None:
return command[1]
elif command[0] is not None:
return command[0]()
raise Error("could not locate runnable browser")
# Please note: the following definition hides a builtin function.
# It is recommended one does "import webbrowser" and uses webbrowser.open(url)
# instead of "from webbrowser import *".
def open(url, new=0, autoraise=True):
"""Display url using the default browser.
If possible, open url in a location determined by new.
- 0: the same browser window (the default).
- 1: a new browser window.
- 2: a new browser page ("tab").
If possible, autoraise raises the window (the default) or not.
If opening the browser succeeds, return True.
If there is a problem, return False.
"""
if _tryorder is None:
with _lock:
if _tryorder is None:
register_standard_browsers()
for name in _tryorder:
browser = get(name)
if browser.open(url, new, autoraise):
return True
return False
def open_new(url):
"""Open url in a new window of the default browser.
If not possible, then open url in the only browser window.
"""
return open(url, 1)
def open_new_tab(url):
"""Open url in a new page ("tab") of the default browser.
If not possible, then the behavior becomes equivalent to open_new().
"""
return open(url, 2)
def _synthesize(browser, *, preferred=False):
"""Attempt to synthesize a controller based on existing controllers.
This is useful to create a controller when a user specifies a path to
an entry in the BROWSER environment variable -- we can copy a general
controller to operate using a specific installation of the desired
browser in this way.
If we can't create a controller in this way, or if there is no
executable for the requested browser, return [None, None].
"""
cmd = browser.split()[0]
if not shutil.which(cmd):
return [None, None]
name = os.path.basename(cmd)
try:
command = _browsers[name.lower()]
except KeyError:
return [None, None]
# now attempt to clone to fit the new name:
controller = command[1]
if controller and name.lower() == controller.basename:
import copy
controller = copy.copy(controller)
controller.name = browser
controller.basename = os.path.basename(browser)
register(browser, None, instance=controller, preferred=preferred)
return [None, controller]
return [None, None]
# General parent classes
class BaseBrowser:
"""Parent class for all browsers. Do not use directly."""
args = ['%s']
def __init__(self, name=""):
self.name = name
self.basename = name
def open(self, url, new=0, autoraise=True):
raise NotImplementedError
def open_new(self, url):
return self.open(url, 1)
def open_new_tab(self, url):
return self.open(url, 2)
class GenericBrowser(BaseBrowser):
"""Class for all browsers started with a command
and without remote functionality."""
def __init__(self, name):
if isinstance(name, str):
self.name = name
self.args = ["%s"]
else:
# name should be a list with arguments
self.name = name[0]
self.args = name[1:]
self.basename = os.path.basename(self.name)
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
cmdline = [self.name] + [arg.replace("%s", url)
for arg in self.args]
try:
if sys.platform[:3] == 'win':
p = subprocess.Popen(cmdline)
else:
p = subprocess.Popen(cmdline, close_fds=True)
return not p.wait()
except OSError:
return False
class BackgroundBrowser(GenericBrowser):
"""Class for all browsers which are to be started in the
background."""
def open(self, url, new=0, autoraise=True):
cmdline = [self.name] + [arg.replace("%s", url)
for arg in self.args]
sys.audit("webbrowser.open", url)
try:
if sys.platform[:3] == 'win':
p = subprocess.Popen(cmdline)
else:
p = subprocess.Popen(cmdline, close_fds=True,
start_new_session=True)
return p.poll() is None
except OSError:
return False
class UnixBrowser(BaseBrowser):
"""Parent class for all Unix browsers with remote functionality."""
raise_opts = None
background = False
redirect_stdout = True
# In remote_args, %s will be replaced with the requested URL. %action will
# be replaced depending on the value of 'new' passed to open.
# remote_action is used for new=0 (open). If newwin is not None, it is
# used for new=1 (open_new). If newtab is not None, it is used for
# new=3 (open_new_tab). After both substitutions are made, any empty
# strings in the transformed remote_args list will be removed.
remote_args = ['%action', '%s']
remote_action = None
remote_action_newwin = None
remote_action_newtab = None
def _invoke(self, args, remote, autoraise, url=None):
raise_opt = []
if remote and self.raise_opts:
# use autoraise argument only for remote invocation
autoraise = int(autoraise)
opt = self.raise_opts[autoraise]
if opt:
raise_opt = [opt]
cmdline = [self.name] + raise_opt + args
if remote or self.background:
inout = subprocess.DEVNULL
else:
# for TTY browsers, we need stdin/out
inout = None
p = subprocess.Popen(cmdline, close_fds=True, stdin=inout,
stdout=(self.redirect_stdout and inout or None),
stderr=inout, start_new_session=True)
if remote:
# wait at most five seconds. If the subprocess is not finished, the
# remote invocation has (hopefully) started a new instance.
try:
rc = p.wait(5)
# if remote call failed, open() will try direct invocation
return not rc
except subprocess.TimeoutExpired:
return True
elif self.background:
if p.poll() is None:
return True
else:
return False
else:
return not p.wait()
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
if new == 0:
action = self.remote_action
elif new == 1:
action = self.remote_action_newwin
elif new == 2:
if self.remote_action_newtab is None:
action = self.remote_action_newwin
else:
action = self.remote_action_newtab
else:
raise Error("Bad 'new' parameter to open(); "
f"expected 0, 1, or 2, got {new}")
args = [arg.replace("%s", url).replace("%action", action)
for arg in self.remote_args]
args = [arg for arg in args if arg]
success = self._invoke(args, True, autoraise, url)
if not success:
# remote invocation failed, try straight way
args = [arg.replace("%s", url) for arg in self.args]
return self._invoke(args, False, False)
else:
return True
class Mozilla(UnixBrowser):
"""Launcher class for Mozilla browsers."""
remote_args = ['%action', '%s']
remote_action = ""
remote_action_newwin = "-new-window"
remote_action_newtab = "-new-tab"
background = True
class Epiphany(UnixBrowser):
"""Launcher class for Epiphany browser."""
raise_opts = ["-noraise", ""]
remote_args = ['%action', '%s']
remote_action = "-n"
remote_action_newwin = "-w"
background = True
class Chrome(UnixBrowser):
"""Launcher class for Google Chrome browser."""
remote_args = ['%action', '%s']
remote_action = ""
remote_action_newwin = "--new-window"
remote_action_newtab = ""
background = True
Chromium = Chrome
class Opera(UnixBrowser):
"""Launcher class for Opera browser."""
remote_args = ['%action', '%s']
remote_action = ""
remote_action_newwin = "--new-window"
remote_action_newtab = ""
background = True
class Elinks(UnixBrowser):
"""Launcher class for Elinks browsers."""
remote_args = ['-remote', 'openURL(%s%action)']
remote_action = ""
remote_action_newwin = ",new-window"
remote_action_newtab = ",new-tab"
background = False
# elinks doesn't like its stdout to be redirected -
# it uses redirected stdout as a signal to do -dump
redirect_stdout = False
class Konqueror(BaseBrowser):
"""Controller for the KDE File Manager (kfm, or Konqueror).
See the output of ``kfmclient --commands``
for more information on the Konqueror remote-control interface.
"""
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
# XXX Currently I know no way to prevent KFM from opening a new win.
if new == 2:
action = "newTab"
else:
action = "openURL"
devnull = subprocess.DEVNULL
try:
p = subprocess.Popen(["kfmclient", action, url],
close_fds=True, stdin=devnull,
stdout=devnull, stderr=devnull)
except OSError:
# fall through to next variant
pass
else:
p.wait()
# kfmclient's return code unfortunately has no meaning as it seems
return True
try:
p = subprocess.Popen(["konqueror", "--silent", url],
close_fds=True, stdin=devnull,
stdout=devnull, stderr=devnull,
start_new_session=True)
except OSError:
# fall through to next variant
pass
else:
if p.poll() is None:
# Should be running now.
return True
try:
p = subprocess.Popen(["kfm", "-d", url],
close_fds=True, stdin=devnull,
stdout=devnull, stderr=devnull,
start_new_session=True)
except OSError:
return False
else:
return p.poll() is None
class Edge(UnixBrowser):
"""Launcher class for Microsoft Edge browser."""
remote_args = ['%action', '%s']
remote_action = ""
remote_action_newwin = "--new-window"
remote_action_newtab = ""
background = True
#
# Platform support for Unix
#
# These are the right tests because all these Unix browsers require either
# a console terminal or an X display to run.
def register_X_browsers():
# use xdg-open if around
if shutil.which("xdg-open"):
register("xdg-open", None, BackgroundBrowser("xdg-open"))
# Opens an appropriate browser for the URL scheme according to
# freedesktop.org settings (GNOME, KDE, XFCE, etc.)
if shutil.which("gio"):
register("gio", None, BackgroundBrowser(["gio", "open", "--", "%s"]))
xdg_desktop = os.getenv("XDG_CURRENT_DESKTOP", "").split(":")
# The default GNOME3 browser
if (("GNOME" in xdg_desktop or
"GNOME_DESKTOP_SESSION_ID" in os.environ) and
shutil.which("gvfs-open")):
register("gvfs-open", None, BackgroundBrowser("gvfs-open"))
# The default KDE browser
if (("KDE" in xdg_desktop or
"KDE_FULL_SESSION" in os.environ) and
shutil.which("kfmclient")):
register("kfmclient", Konqueror, Konqueror("kfmclient"))
# Common symbolic link for the default X11 browser
if shutil.which("x-www-browser"):
register("x-www-browser", None, BackgroundBrowser("x-www-browser"))
# The Mozilla browsers
for browser in ("firefox", "iceweasel", "seamonkey", "mozilla-firefox",
"mozilla"):
if shutil.which(browser):
register(browser, None, Mozilla(browser))
# Konqueror/kfm, the KDE browser.
if shutil.which("kfm"):
register("kfm", Konqueror, Konqueror("kfm"))
elif shutil.which("konqueror"):
register("konqueror", Konqueror, Konqueror("konqueror"))
# Gnome's Epiphany
if shutil.which("epiphany"):
register("epiphany", None, Epiphany("epiphany"))
# Google Chrome/Chromium browsers
for browser in ("google-chrome", "chrome", "chromium", "chromium-browser"):
if shutil.which(browser):
register(browser, None, Chrome(browser))
# Opera, quite popular
if shutil.which("opera"):
register("opera", None, Opera("opera"))
if shutil.which("microsoft-edge"):
register("microsoft-edge", None, Edge("microsoft-edge"))
def register_standard_browsers():
global _tryorder
_tryorder = []
if sys.platform == 'darwin':
register("MacOSX", None, MacOSXOSAScript('default'))
register("chrome", None, MacOSXOSAScript('chrome'))
register("firefox", None, MacOSXOSAScript('firefox'))
register("safari", None, MacOSXOSAScript('safari'))
# OS X can use below Unix support (but we prefer using the OS X
# specific stuff)
if sys.platform == "ios":
register("iosbrowser", None, IOSBrowser(), preferred=True)
if sys.platform == "serenityos":
# SerenityOS webbrowser, simply called "Browser".
register("Browser", None, BackgroundBrowser("Browser"))
if sys.platform[:3] == "win":
# First try to use the default Windows browser
register("windows-default", WindowsDefault)
# Detect some common Windows browsers, fallback to Microsoft Edge
# location in 64-bit Windows
edge64 = os.path.join(os.environ.get("PROGRAMFILES(x86)", "C:\\Program Files (x86)"),
"Microsoft\\Edge\\Application\\msedge.exe")
# location in 32-bit Windows
edge32 = os.path.join(os.environ.get("PROGRAMFILES", "C:\\Program Files"),
"Microsoft\\Edge\\Application\\msedge.exe")
for browser in ("firefox", "seamonkey", "mozilla", "chrome",
"opera", edge64, edge32):
if shutil.which(browser):
register(browser, None, BackgroundBrowser(browser))
if shutil.which("MicrosoftEdge.exe"):
register("microsoft-edge", None, Edge("MicrosoftEdge.exe"))
else:
# Prefer X browsers if present
#
# NOTE: Do not check for X11 browser on macOS,
# XQuartz installation sets a DISPLAY environment variable and will
# autostart when someone tries to access the display. Mac users in
# general don't need an X11 browser.
if sys.platform != "darwin" and (os.environ.get("DISPLAY") or os.environ.get("WAYLAND_DISPLAY")):
try:
cmd = "xdg-settings get default-web-browser".split()
raw_result = subprocess.check_output(cmd, stderr=subprocess.DEVNULL)
result = raw_result.decode().strip()
except (FileNotFoundError, subprocess.CalledProcessError,
PermissionError, NotADirectoryError):
pass
else:
global _os_preferred_browser
_os_preferred_browser = result
register_X_browsers()
# Also try console browsers
if os.environ.get("TERM"):
# Common symbolic link for the default text-based browser
if shutil.which("www-browser"):
register("www-browser", None, GenericBrowser("www-browser"))
# The Links/elinks browsers <http://links.twibright.com/>
if shutil.which("links"):
register("links", None, GenericBrowser("links"))
if shutil.which("elinks"):
register("elinks", None, Elinks("elinks"))
# The Lynx browser <https://lynx.invisible-island.net/>, <http://lynx.browser.org/>
if shutil.which("lynx"):
register("lynx", None, GenericBrowser("lynx"))
# The w3m browser <http://w3m.sourceforge.net/>
if shutil.which("w3m"):
register("w3m", None, GenericBrowser("w3m"))
# OK, now that we know what the default preference orders for each
# platform are, allow user to override them with the BROWSER variable.
if "BROWSER" in os.environ:
userchoices = os.environ["BROWSER"].split(os.pathsep)
userchoices.reverse()
# Treat choices in same way as if passed into get() but do register
# and prepend to _tryorder
for cmdline in userchoices:
if cmdline != '':
cmd = _synthesize(cmdline, preferred=True)
if cmd[1] is None:
register(cmdline, None, GenericBrowser(cmdline), preferred=True)
# what to do if _tryorder is now empty?
#
# Platform support for Windows
#
if sys.platform[:3] == "win":
class WindowsDefault(BaseBrowser):
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
try:
os.startfile(url)
except OSError:
# [Error 22] No application is associated with the specified
# file for this operation: '<URL>'
return False
else:
return True
#
# Platform support for macOS
#
if sys.platform == 'darwin':
class MacOSXOSAScript(BaseBrowser):
def __init__(self, name='default'):
super().__init__(name)
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
url = url.replace('"', '%22')
if self.name == 'default':
script = f'open location "{url}"' # opens in default browser
else:
script = f'''
tell application "{self.name}"
activate
open location "{url}"
end
'''
osapipe = os.popen("osascript", "w")
if osapipe is None:
return False
osapipe.write(script)
rc = osapipe.close()
return not rc
#
# Platform support for iOS
#
if sys.platform == "ios":
from _ios_support import objc
if objc:
# If objc exists, we know ctypes is also importable.
from ctypes import c_void_p, c_char_p, c_ulong
class IOSBrowser(BaseBrowser):
def open(self, url, new=0, autoraise=True):
sys.audit("webbrowser.open", url)
# If ctypes isn't available, we can't open a browser
if objc is None:
return False
# All the messages in this call return object references.
objc.objc_msgSend.restype = c_void_p
# This is the equivalent of:
# NSString url_string =
# [NSString stringWithCString:url.encode("utf-8")
# encoding:NSUTF8StringEncoding];
NSString = objc.objc_getClass(b"NSString")
constructor = objc.sel_registerName(b"stringWithCString:encoding:")
objc.objc_msgSend.argtypes = [c_void_p, c_void_p, c_char_p, c_ulong]
url_string = objc.objc_msgSend(
NSString,
constructor,
url.encode("utf-8"),
4, # NSUTF8StringEncoding = 4
)
# Create an NSURL object representing the URL
# This is the equivalent of:
# NSURL *nsurl = [NSURL URLWithString:url];
NSURL = objc.objc_getClass(b"NSURL")
urlWithString_ = objc.sel_registerName(b"URLWithString:")
objc.objc_msgSend.argtypes = [c_void_p, c_void_p, c_void_p]
ns_url = objc.objc_msgSend(NSURL, urlWithString_, url_string)
# Get the shared UIApplication instance
# This code is the equivalent of:
# UIApplication shared_app = [UIApplication sharedApplication]
UIApplication = objc.objc_getClass(b"UIApplication")
sharedApplication = objc.sel_registerName(b"sharedApplication")
objc.objc_msgSend.argtypes = [c_void_p, c_void_p]
shared_app = objc.objc_msgSend(UIApplication, sharedApplication)
# Open the URL on the shared application
# This code is the equivalent of:
# [shared_app openURL:ns_url
# options:NIL
# completionHandler:NIL];
openURL_ = objc.sel_registerName(b"openURL:options:completionHandler:")
objc.objc_msgSend.argtypes = [
c_void_p, c_void_p, c_void_p, c_void_p, c_void_p
]
# Method returns void
objc.objc_msgSend.restype = None
objc.objc_msgSend(shared_app, openURL_, ns_url, None, None)
return True
def parse_args(arg_list: list[str] | None):
import argparse
parser = argparse.ArgumentParser(description="Open URL in a web browser.")
parser.add_argument("url", help="URL to open")
group = parser.add_mutually_exclusive_group()
group.add_argument("-n", "--new-window", action="store_const",
const=1, default=0, dest="new_win",
help="open new window")
group.add_argument("-t", "--new-tab", action="store_const",
const=2, default=0, dest="new_win",
help="open new tab")
args = parser.parse_args(arg_list)
return args
def main(arg_list: list[str] | None = None):
args = parse_args(arg_list)
open(args.url, args.new_win)
print("\a")
if __name__ == "__main__":
main()