The new life of command interfaces

g/christensen · September 1, 2019

Enso Launcher   Python

Command interfaces - an integral part of life in the 1980s - gain a new breath with the advent of Enso Launcher and iShell Extension. Although graphical user interfaces have opened a new world in the computer industry, in certain domains text commands still offer advantages in usability and accessibility. With the tools mentioned above, you can create powerful commands that will free you from routine GUI interactions.

An example of a custom command

Let’s assume that you have a large random dump of music videos that you want to sort to watch on your media-center PC. Normally, to sort files you open a video in a player, assess it, stop playback, close the video, and navigate to the file explorer to move the video into the corresponding destination directory. Obviously, this takes a fair amount of manual actions.

Enso Launcher (v0.4.5+) allows you to make a command, let’s call it mv, that will automatically move a file opened in Media Player Classic to the directory specified as a command argument. Moreover, by using Enso mediaprobes you can populate MPC playlist from the filesystem with no more than one command.

To be more specific, let’s assume that you have made the following directory tree of the destination music video categories:

D:/music
    ├───live
    │   ├───classical
    │   ├───heavy metal
    │   └───pop music
    └───music videos
        ├───classical
        ├───heavy metal
        └───pop music

Below we create the mv command that will help us to move files currently displayed in MPC to the directories shown above. It will have the following syntax: mv category.

We will also be able to open the resulting directories in MPC with commands that correspond to the top-level folders (live and music videos), for example, in the form: live classical.

The commands in action are displayed on the video below.

You may explore the code in the Enso command editor. The commands are completely data-driven - the result will change whenever you modify the directory tree.

Obtaining the music directories as command arguments

Since there are two levels of video categories, we need to pack both into a single argument name. Let’s take the first letter of the first level (for example ‘l’ for ‘live) and prepend it to the full name of the second level, so we get ‘lclassical’, ‘mclassical’, etc. as command arguments. The same approach is applicable if there are more levels, but it may utilize some separator character.

import os

MEDIA_ROOT = "d:/music"
 
def generate_category_args():  
    # Get 'live', 'music videos' and any other folders.
    supercats = os.listdir(MEDIA_ROOT)
    
    result = []
    
    for supercat in supercats:
        # Get 'classical', 'heavy metal' and any other folders.
        cats = os.listdir(os.path.join(MEDIA_ROOT, supercat))

        # The resulting argument names will consist of the first letter of
        # a super-category and the full sub-category name.
        # If some super-categories begin with the same letter, add more   
        # starting letters to the argument name.
        for cat in cats:
            result += [supercat[0] + cat]

    return result

Creating the ‘mv’ command

It is possible to install Enso with a set of MPC-related commands bundled with mpcapi library. We will use it in our ‘mv’ command below. You also need to enable Web UI in MPC settings.

import re, requests, shutil, time
import mpcapi # You need to install Enso with MPC option enabled.

MPC_HOST = "127.0.0.1"
MPC_PORT = "13579"

def cmd_mv(ensoapi, cat):
    # Map the first letter of all super-categories to their full names.
    supercats = dict(((sc[0], sc) for sc in os.listdir(MEDIA_ROOT)))
    
    # Get super-category of argument.
    supercat = supercats[cat[0]]
    # Compose destination directory path from the argument name.
    dest = os.path.join(MEDIA_ROOT, supercat, cat[1:])
    
    # Get the full path of the file currently opened in MPC.
    page = requests.get("http://" + MPC_HOST + ":" + MPC_PORT + "/variables.html")
    file = re.search("id=\"filepath\">([^<]*)<", page.text).group(1)
    # The full destination path with file name.
    dest_file = os.path.join(dest, os.path.basename(file))
    
    # Instantiate the MPC client.
    mpc = mpcapi.MpcAPI(host=MPC_HOST, port=MPC_PORT)
    
    if not os.path.exists(dest_file):
        mpc.close()      # Stop playback and close the current file.
        time.sleep(1)
        shutil.move(file, dest)
        mpc.play()       # Play the next file.

cmd_mv.valid_args = generate_category_args()

# A little helper command which lists available video categories.
def cmd_wheremv(ensoapi):
    ensoapi.display_message(", ".join(cmd_mv.valid_args))

# MPC is also able to delete videos, so here is 'rm' command.
def cmd_rm(ensoapi):
    mpcapi.MpcAPI(host=MPC_HOST, port=MPC_PORT).move_to_recycle_bin()

Creating mediaprobes for ‘d:/music’ subfolders

In the snippet below we create two commands named: ‘live’ and ‘music videos’. These commands automatically obtain subcategories from the corresponding folders as their own arguments and pass them to MPC. There will be as many probe commands as subdirectories in ‘d:/music’. See the Enso tutorial and API documentation for more details.

from enso.user import mediaprobe

# The full path to the MPC executable may be different on your system.
PLAYER = "C:/Program Files (x86)/MPC-HC64/mpc-hc64.exe"

mkcat = lambda c: os.path.join(MEDIA_ROOT, c)

for supercat in os.listdir(MEDIA_ROOT):
    cmdname = "cmd_" + supercat.replace(" ", "_")
    globals()[cmdname] = mediaprobe.directory_probe("cat", mkcat(supercat), PLAYER)

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