sway-launcher-desktop

sway-launcher-desktop.sh

#!/usr/bin/env bash
# terminal application launcher for sway, using fzf
# Based on: https://gitlab.com/FlyingWombat/my-scripts/blob/master/sway-launcher

shopt -s nullglob
if [[ "$1" == 'describe' ]]; then
  shift
  if [[ $2 == 'command' ]]; then
    title=$1
    readarray arr < <(whatis -l "$1" 2>/dev/null)
    description="${arr[0]}"
    description="${description%*-}"
  else
    title=$(sed -ne '/^Name=/{s/^Name=//;p;q}' "$1")
    description=$(sed -ne '/^Comment=/{s/^Comment=//;p;q}' "$1")
  fi
  echo -e "\033[33m$title\033[0m"
  echo "${description:-No description}"
  exit
fi

HIST_FILE="${XDG_CACHE_HOME:-$HOME/.cache}/${0##*/}-history.txt"

DIRS=(
  /usr/share/applications
  "$HOME/.local/share/applications"
  /usr/local/share/applications
)

GLYPH_COMMAND="  "
GLYPH_DESKTOP="  "

touch "$HIST_FILE"
readarray HIST_LINES <"$HIST_FILE"
FZFPIPE=$(mktemp)
PIDFILE=$(mktemp)
trap 'rm "$FZFPIPE" "$PIDFILE"' EXIT INT

# Append Launcher History, removing usage count
(printf '%s' "${HIST_LINES[@]#* }" >>"$FZFPIPE") &

# Load and append Desktop entries
(
  for dir in "${DIRS[@]}"; do
    [[ -d "$dir" ]] || continue
    awk -v pre="$GLYPH_DESKTOP" -F= '
                BEGINFILE{application=0;block="";a=0}
                /^\[Desktop Entry\]/{block="entry"}
                /^Type=Application/{application=1}
                /^\[Desktop Action/{
                  sub("^\\[Desktop Action ", "");
                  sub("\\]$", "");
                  block="action";
                  a++;
                  actions[a,"key"]=$0
                }
                /^Name=/{
                if(block=="action") {
                    actions[a,"name"]=$2;
                } else {
                    name=$2
                }
                }
                ENDFILE{
                  if (application){
                      print FILENAME "\034desktop\034\033[33m" pre name "\033[0m";
                      if (a>0)
                          for (i=1; i<=a; i++)
                              print FILENAME "\034desktop\034\033[33m" pre name "\033[0m (" actions[i, "name"] ")\034" actions[i, "key"]
                  }
                }' \
      "$dir/"*.desktop </dev/null >>"$FZFPIPE"
    # the empty stdin is needed in case no *.desktop files
  done
) &

# Load and append command list
(
  IFS=:
  read -ra path <<<"$PATH"
  for dir in "${path[@]}"; do
    printf '%s\n' "$dir/"* |
      awk -F / -v pre="$GLYPH_COMMAND" '{print $NF "\034command\034\033[31m" pre "\033[0m" $NF;}'
  done | sort -u >>"$FZFPIPE"
) &

COMMAND_STR=$(
  (
    tail -n +0 -f "$FZFPIPE" &
    echo $! >"$PIDFILE"
  ) |
    fzf +s -x -d '\034' --nth ..3 --with-nth 3 \
      --preview "$0 describe {1} {2}" \
      --preview-window=up:3:wrap --ansi
  kill -9 "$(<"$PIDFILE")" | tail -n1
) || exit 1

[ -z "$COMMAND_STR" ] && exit 1

# update history
for i in "${!HIST_LINES[@]}"; do
  if [[ "${HIST_LINES[i]}" == *" $COMMAND_STR"$'\n' ]]; then
    HIST_COUNT=${HIST_LINES[i]%% *}
    HIST_LINES[$i]="$((HIST_COUNT + 1)) $COMMAND_STR"$'\n'
    match=1
    break
  fi
done
if ! ((match)); then
  HIST_LINES+=("1 $COMMAND_STR"$'\n')
fi

printf '%s' "${HIST_LINES[@]}" | sort -nr >"$HIST_FILE"

command='echo "nope"'
# shellcheck disable=SC2086
readarray -d $'\034' -t PARAMS <<<${COMMAND_STR}
# COMMAND_STR is "<string>\034<type>"
case ${PARAMS[1]} in
desktop)
  # Define the search pattern that specifies the block to search for within the .desktop file
  PATTERN="^\\\\[Desktop Entry\\\\]"
  if [[ -n ${PARAMS[3]} ]]; then
    PATTERN="^\\\\[Desktop Action ${PARAMS[3]%?}\\\\]"
  fi
  # 1. We see a line starting [Desktop, but we're already searching: deactivate search again
  # 2. We see the specified pattern: start search
  # 3. We see an Exec= line during search: remove field codes and set variable
  # 3. We see a Path= line during search: set variable
  # 4. Finally, build command line
  command=$(awk -v pattern="${PATTERN}" -F= '
                BEGIN{a=0;exec=0; path=0}
                   /^\[Desktop/{
                    if(a){
                      a=0
                    }
                   }
                  $0 ~ pattern{
                   a=1
                  }
                  /^Exec=/{
                    if(a && !exec){
                      sub("^Exec=", "");
                      gsub(" ?%[cDdFfikmNnUuv]", "");
                      exec=$0;
                    }
                  }
                  /^Path=/{
                    if(a && !path){
                      path=$2
                    }
                   }

                END{
                  if(path){
                    print "cd " path " &&"
                  }
                  print exec
                }' "${PARAMS[0]}")
  ;;
command)
  command="${PARAMS[0]}"
  ;;
esac
swaymsg -t command exec "$command"

I have also pushed a small update which made the error disappear once I was able to reproduce it.

I'm not sure how to deal with the multiple desktop actions though. I guess the safe thing would be to extract multiple starter items instead of attempting to sport the right one.

That is what things like i3-dmenu-desktop and alike do. If I can be as bold as to suggest something. I would personally go for something like Firefox (New Window) so that would be <application name> (<action name>). I'm no AWK expert in the slightest. but that might be a hard task to accomplish, but this is gearing more and more towards full fledged ini parsing, which might not be a bad idea after all, but is probably not the best fit for a shell only solution.
I must admit. I kinda feel inspired to do build something in Rust or C if I can find the time in a couple of weeks.

Okay I might have gotten a little excited. I'm terrible at AWK and learned quite a bit writing this, but this might be an okay start. If it's crap, feel free to ignore it ;)

awk -v pre="$GLYPH_DESKTOP" -F= '
            BEGINFILE{application=0;block="";application_name=""}
            /^\[Desktop Entry\]/{block="entry"}
            /^Type=Application/{application=1}
            /^\[Desktop Action/{block="action";a++}
            /^Name=/{
            if(block=="action") {
                actions[a,"name"]=$2;
            } else {
                name=$2
            }
            }
            ENDFILE{
            if (application)
                if (a>0)
                    for (i=1; i<=a; i++)
                        print FILENAME "|desktop|\033[33m" pre name " (" actions[i, "name"] ")\033[0m"
                else
                    print FILENAME "|desktop|\033[33m" pre name "\033[0m";}' \

Awesome, thank you very much! This is pretty much what I had in mind, but I too have a lot to learn using awk. You still need to reset a in BEGINFILE and as far as I can tell the application_name is unused. But this works great as far as extracting the launcher items goes.
We still need to filter out the correct Exec= command when the item is actually run though.

I have just pushed a large update inspired by your post. However, I had to make quite a few changes:

• For executing a specific entry, we need a machine-friendly way to pass that information, so I added a new column in the line structure
• This column contains the action specifier (instead of the human-friendly Name= field)
• Fields are now separated by the non-printable \034 character. This ensures fzf will not print the delimiter
• It also prevents any potential problems from the previous | character appearing in Exec= statements
• Using the new action specifier, we can craft a specific pattern for awk to search, falling back to /^\[Desktop Entry if it's not present
• Then command and working dir are extracted and poof: I can now open a new private tab in Firefox

cc @DanielVoogsgerd @nstickney

Legend! This is working incredibly well. I'll test it out and see what happens. Again, thanks for all the hard work. This was precisely what I was looking for!

EDIT: Now I'm thinking for it. Maybe listing the GenericName and or Categories in the describe might be a fun extra.

@DanielVoogsgerd
Absolutely. I just did not work on that part yet because it's low-hanging fruit. But I realized that there is more useful info to find in those desktop files and in most cases, there is free space where we can put it.

Other things I am thinking about:

• Think about how this script could use and benefit from external configuration
• Implement file search and pass paths to xdg-open. I usually hate when launchers include a file search, but if it's optional and fully configurable (->by passing), I might use it myself.
• Come up with fun usages of fzf keybindings
• Implement a function that can be called externally and decrements all history usage entries and deletes a line if it reaches 0. Users could put the command in a cron/systemd-timer and then is would gradually phase out entries that you only rarely need and prevent your history from becoming a mess over time
• If the above proves to be a useful addition, you might then want to be able to select favourites that never get cleaned up ( and are probably are excluded from the history anyway )

We'll see how much time and motivation I find for these things. If things get serious, this gist should turn into a proper repository, though.

Wow, this started out good and got way, way good.... Thanks @Biont (and @DanielVoogsgerd)!

Maybe it's an idea to create a repository from this snippets so issues can be multi-threaded and contributions can be made more easily. Also I'm curious as to which license you want to use to publish to code.
Edit: Whoops, I missed your last remark about the repository.

So, I've found another issue, and I believe I have a solution, but I'm a n00b here, so check me.

PROBLEM:
Some *.desktop files include not just the command, but also environment variables, in the Exec line, i.e. "Exec=env GDK_BACKEND=x11 /opt/minecraft-launcher/minecraft-launcher". This is apparently a standard pattern, but swaymsg -t command "$command" leads to Error: Unknown/invalid command 'env'. I tried changing the Exec line to /usr/bin/env, but I get a similar message: Error: Unknown/invalid command '/usr/bin/env'.

SOLUTION:
I changed the way the $command variable is formatted by removing the line break and replacing it with a space. Then, when running the command, I cut out env using bash string substitution.

EDIT:
Note, I also changed the ordering of the $DIRS hoping to make the ~/.local entry override the others, but I don't believe it has any effect.

@Biont I updated the script to handle Terminal=true in desktop files so they open in a terminal (my original use case for this was opening ranger). Seems like this could be useful in the core script, but it's currently hardcoded to use termite. I could extract it into an environment variable for now, probably the simplest way to solve the problem without having to search for different terminals. Seems like +1 use case for configuration.

@nstickney @joefiorini Thank you both! I have created an actual repository for this project so we can use issues and PRs in the future: https://github.com/Biont/sway-launcher-desktop/tree/master

I will look at your suggestions asap.

@Biont I just updated mine to make the terminal command an env var so it's easier to change. I'll send a PR with this update to make it easier for you to review and pull in if you want it.

is there any way i can make it look into /opt? adding it to DIRS doesn't seem to do the trick... or read .desktop files, that would work as well.

Hi @Emaleth Can you please open an issue over here?

This script has evolved into its own repo and I should probably delete this gist..