terminanting bash script from background job

[fzwd]

Was having problems getting to play mp3 off the web right so thought to make a shell program do that........ here's part of it

function download ()
{
  WGETLOG="playmp3.wget-log"
  MEDIAFILE=~/Download/`echo $URI | sed 's:^.*/:: ; s:[^a-zA-Z0-9\.]+:-:g'`
  
  #run wget in background
  ( wget  -O $MEDIAFILE -o $WGETLOG $URI 
    if [ $? ] ; then echo "ERROR: wget ... $URI" ; exit 1; fi ) &
}


#.................................
case $1 in
*m3u)
  URI=`cat $1`
  download

  #wait for something to be buffered
  sleep 20
  #convert to wav whatever is downloaded so far & play
  play
  ;;

so my problem here is if wget doesn't connect how to stop it from try to play the file.... as this doesn't work as written

[atreyu]

well, there are things i'd do differently, but here is a quick fix you can try:

#!/bin/bash

function download() {

  WGETLOG="playmp3.wget-log"
  MEDIAFILE=~/Download/`echo $URI | sed 's:^.*/:: ; s:[^a-zA-Z0-9\.]+:-:g'`
  
  #run wget in background
  wget --background -O $MEDIAFILE -o $WGETLOG $URI

  # it is good practice to return an exit value from functions,
  # instead of simply exiting
  return $?
}

#.................................
case $1 in
*m3u)
  URI=`cat $1`
  # now when we call this function, exit if it did not return successfully
  download
  rc=$?
  if [ $rc -ne 0 ]; then
    echo "wget returned exit code $rc -aborting"
    exit $rc
  fi

  #wait for something to be buffered
  sleep 20
  #convert to wav whatever is downloaded so far & play
  play
  ;;
esac

[fzwd]

thanks for the reply atreyu.

As I understand $? that only works on foreground tasks. And I had seen the --background switch but the problem is wget didn't show up jobs as I do kill `jobs -p` to stop all the background tasks at the end of the script.....

[atreyu]

thanks for the reply atreyu.

As I understand $? that only works on foreground tasks. And I had seen the --background switch but the problem is wget didn't show up jobs as I do kill `jobs -p` to stop all the background tasks at the end of the script.....

okay, so maybe you should explain what kind errors you are expecting from wget. there may be better ways to determine if there is a problem with it (like examining the wget-log, for one).

also, what process(es) are you trying to kill? wget? why, if I may ask? you can use pidof to get the pid of wget (or whatever) and kill it that way. or you can get the pid of the last executed command using the $! variable, and use that.

[fzwd]

okay, so maybe you should explain what kind errors you are expecting from wget. there may be better ways to determine if there is a problem with it (like examining the wget-log, for one).

also, what process(es) are you trying to kill? wget? why, if I may ask? you can use pidof to get the pid of wget (or whatever) and kill it that way. or you can get the pid of the last executed command using the $! variable, and use that.

( wget  -O $MEDIAFILE -o $WGETLOG $URI 
    if [ $? ] ; then echo "ERROR WGET"; kill $$;  fi ) &

I had found that kills the script but your idea to search wget-log is better. tried another site it retrieve an html page instead....

the other running processes would( wget, lame, aplay ) basically the Im listening the song just enough to see if its something I could do something with. Totem I guess would have been rebuilt, since I cant adjust the buffer, and wouldnt allow replaying without restarting the streaming. and also if was something I could do something with it would already downloaded.

[atreyu]

( wget  -O $MEDIAFILE -o $WGETLOG $URI 
    if [ $? ] ; then echo "ERROR WGET"; kill $$;  fi ) &

I had found that kills the script but your idea to search wget-log is better.

that is because $$ is the pid of the current process. you'd want $!, which is the pid of the last executed process.

tried another site it retrieve an html page instead....

what do you mean? that sounds like you had an incorrect URL...or maybe you just have to parse the log and look for a specific error?

the other running processes would( wget, lame, aplay ) basically the Im listening the song just enough to see if its something I could do something with. Totem I guess would have been rebuilt, since I cant adjust the buffer, and wouldnt allow replaying without restarting the streaming. and also if was something I could do something with it would already downloaded.

okay, now that I understand better, this is what I'd recommend: create a separate script that does the converting/playing, and have your URL downloading script call it.

what is your main problem, though: is it that you want to kill wget in mid-download, after you've played the partially downloaded file? or is it that if wget has a problem, correctly detect that problem and quit the d/l script? or something else?