获取 gphoto2 的当前状态

Question

我有 gphoto 运行一个 --wait-event-and-download 参数，这样我用红外遥控器拍摄的照片就会保存到电脑上。

我设置了第二个脚本来中断等待过程并以编程方式拍照，如下所示：

#!/bin/sh
# shootnow.sh - stop the current gphoto2 process (if it exists),
# shoot a new image, then start a new wait-event process.

pkill -INT gphoto2     #send interrupt (i.e. ctrl+c) to gphoto2
sleep 0.1              #avoid the process ownership error
gphoto2 --capture-image-and-download  #take a picture now
gphoto2 --wait-event-and-download   #start a new wait-event process

但我想确保第一个等待事件进程当前没有在我中断它之前下载图像（这会导致图像填满相机内存的混乱情况，从而阻止进一步的操作）。所以第二个脚本应该更像这样：

#!/bin/sh
# shootnow-with-check.sh - stop the current gphoto2 process (if it exists 
# and isn't currently downloading an image), shoot a new image, then start 
# a new wait-event process.

shootnow() {  # same as previously, but now in a function
    pkill -INT gphoto2
    sleep 0.1
    gphoto2 --capture-image-and-download
    gphoto2 --wait-event-and-download
}

if [ ***current output line of gphoto2 process doesnt start with "Downloading"*** ] then
    shootnow
else
    echo "Capture aborted - a picture was just taken and is being saved."
fi

任何人都可以帮我解决 if 语句吗？我可以读取运行 gphoto 进程的当前输出行吗？

Answer 1

我最终用这样的脚本解决了这个问题：

#!/bin/bash
# gphoto2-expect.sh
# use expect to monitor gphoto2 during --capture-image-and-download with
# --interval=-1, adding in SIGUSR1 functionality except during a
# download event.

echo "Prepping system for camera"
killall PTPCamera
expect << 'EOS'
puts "Starting capture..."
if [catch "spawn gphoto2 --capture-image-and-download --interval=-1" gp_pid] {
  Log $ERROR "Unable to start gphoto2.\n$gp_pid\n"
  return 0
}

trap {exec kill -SIGUSR1 $gp_pid} SIGUSR1
set timeout -1
expect {
  -i $spawn_id
  "Downloading" {
    trap {send_user "\n Ignoring request as currently downloading"} SIGUSR1 ; exp_continue
  }
  "Saving file as" {
    sleep 0.1
    trap {exec kill -SIGUSR1 $gp_pid} SIGUSR1 ; exp_continue
  }
}

EOS

可以用另一个脚本触发：

#!/bin/bash
# trigger.sh - trigger an immediate capture
var=$(pidof expect)
kill -SIGUSR1 "$var"

Answer 2

gphoto2 有一个选项 --hook-script FILENAME。 FILENAME 必须是一个可执行的脚本，并且在某些 gphoto2 事件中被调用。然后该脚本有一个环境变量 ACTION，您可以将其用于您的目的。例如：你用

调用 gphoto2

gphoto2 --capture-image-and-download --hook-script myhook.sh

和myhook.sh看起来像

#! /bin/bash
echo $ACTION

那么myhook.sh会被调用4次。它的输出是

init
start
download
stop

有关详细信息，请参阅 man gphoto2。

获取 gphoto2 的当前状态

get current status of gphoto2

macos

sh

libgphoto2