问题描述
我需要等到用户在默认图形应用程序(Debian 和衍生产品)中编辑完文本文件。
如果我将 xdg-open 与 subprocess.call(通常等待)一起使用,它将在编辑器中打开文件后继续。我假设是因为 xdg-open 本身异步启动编辑器。
通过检索 text/plain mime-type 的启动器并将其与 Gio.DesktopAppInfo.new 一起使用,我终于获得了或多或少的工作代码以获取编辑器的命令。前提是编辑器尚未打开,在这种情况下,编辑器仍处于打开状态时过程结束。
我添加了检查 process.pid 和轮询进程的解决方案。两者都以无限循环结束。
等待过程完成似乎过于复杂。那么,有没有更强大的方法来做到这一点?
#! /usr/bin/env python3
import subprocess
from gi.repository import Gio
import os
from time import sleep
import sys
def open_launcher(my_file):
print('launcher open')
app = subprocess.check_output(['xdg-mime','query','default','text/plain']).decode('utf-8').strip()
print(app)
launcher = Gio.DesktopAppInfo.new(app).get_commandline().split()[0]
print(launcher)
subprocess.call([launcher,my_file])
print('launcher close')
def open_xdg(my_file):
print('xdg open')
subprocess.call(['xdg-open',my_file])
print('xdg close')
def check_pid(pid):
""" Check For the existence of a unix pid. """
try:
os.kill(int(pid),0)
except OSError:
return False
else:
return True
def open_pid(my_file):
pid = subprocess.Popen(['xdg-open',my_file]).pid
while check_pid(pid):
print(pid)
sleep(1)
def open_poll(my_file):
proc = subprocess.Popen(['xdg-open',my_file])
while not proc.poll():
print(proc.poll())
sleep(1)
def open_ps(my_file):
subprocess.call(['xdg-open',my_file])
pid = subprocess.check_output("ps -o pid,cmd -e | grep %s | head -n 1 | awk '{print $1}'" % my_file,shell=True).decode('utf-8')
while check_pid(pid):
print(pid)
sleep(1)
def open_popen(my_file):
print('popen open')
process = subprocess.Popen(['xdg-open',my_file])
process.wait()
print(process.returncode)
print('popen close')
# This will end the open_xdg function while the editor is open.
# However,if the editor is already open,open_launcher will finish while the editor is still open.
#open_launcher('test.txt')
# This solution opens the file but the process terminates before the editor is closed.
#open_xdg('test.txt')
# This will loop indefinately printing the pid even after closing the editor.
# If you check for the pid in another terminal you see the pid with: [xdg-open] <defunct>.
#open_pid('test.txt')
# This will print None once after which 0 is printed indefinately: the subprocess ends immediately.
#open_poll('test.txt')
# This seems to work,even when the editor is already open.
# However,I had to use head -n 1 to prevent returning multiple pids.
#open_ps('test.txt')
# Like open_xdg,this opens the file but the process terminates before the editor is closed.
open_popen('test.txt')
解决方法
您可以简单地等待子进程终止,而不是尝试轮询 PID,使用 subprocess.Popen.wait()
:
等待子进程终止。设置并返回返回码属性。
此外,不能保证获得 get_commandline()
的第一部分就是启动器。 get_commandline()
返回的字符串将匹配 the Exec
key spec,这意味着返回的字符串中的 %u
、%U
、%f
和 %F
字段代码应该替换为正确的值。
以下是一些示例代码,基于您的 xdg-mime
方法:
#!/usr/bin/env python3
import subprocess
import shlex
from gi.repository import Gio
my_file = 'test.txt'
# Get default application
app = subprocess.check_output(['xdg-mime','query','default','text/plain']).decode('utf-8').strip()
# Get command to run
command = Gio.DesktopAppInfo.new(app).get_commandline()
# Handle file paths with spaces by quoting the file path
my_file_quoted = "'" + my_file + "'"
# Replace field codes with the file path
# Also handle special case of the atom editor
command = command.replace('%u',my_file_quoted)\
.replace('%U',my_file_quoted)\
.replace('%f',my_file_quoted)\
.replace('%F',my_file_quoted if app != 'atom.desktop' else '--wait ' + my_file_quoted)
# Run the default application,and wait for it to terminate
process = subprocess.Popen(
shlex.split(command),stdout=subprocess.DEVNULL,stderr=subprocess.DEVNULL)
process.wait()
# Now the exit code of the text editor process is available as process.returncode
我对我的示例代码有几点说明。
备注 1:处理文件路径中的空格
要打开的文件路径用引号括起来很重要,否则 shlex.split(command)
会将文件名分割为空格。
备注 2:转义 %
个字符
文字百分比字符必须转义为 %%。
我对 replace()
的使用可能会替换 %
被转义的字符。为简单起见,我选择忽略这种边缘情况。
备注 3:原子
我假设所需的行为是始终等到图形编辑器关闭。对于 atom 文本编辑器,除非提供 --wait
选项,否则它将在启动窗口时立即终止。因此,如果默认编辑器是 atom,我有条件地添加 --wait
选项。
备注 4:subprocess.DEVNULL
subprocess.DEVNULL
是 python 3.3 中的新内容。对于较旧的 python 版本,可以使用以下内容:
with open(os.devnull,'w') as DEVNULL:
process = subprocess.Popen(
shlex.split(command),stdout=DEVNULL,stderr=DEVNULL)
测试
我使用 GNOME 桌面环境在 Ubuntu 上测试了上面的示例代码。我使用以下图形文本编辑器进行了测试:gedit、mousepad 和 atom。