Generate access_token from client_id and client_secret; cache it with timestamp; comment code

.env.template

@@ -1,7 +1,8 @@
 # Authentification
 sp_id=""
 sp_password=""
-sp_token=""
+sp_client_id=""
+sp_client_secret=""
 
 # Tracks format and location
 output="$HOME/music"

.gitignore

@@ -1,2 +1,3 @@
 lib/
 .env
+.token_cache

README.md

@@ -5,8 +5,8 @@ This is not a youtube scrapper. This is a real Spotify music downloader, to mp3
 
 **You will need a premium account to Spotify and set your ids in `.env` file,** and configure your tracks output format and custom location.
 
-If you want to use keywords search, you will also need a developer token, set to the same file (TODO: bypass this token).
-You can get this token here: https://developer.spotify.com/console/get-search-item/, but this one expire after one hour...
+If you want to use keywords search, you will also need `client_id` and `client_secret`, set to the same file (TODO: bypass this ids).
+You can get this ids here: https://developer.spotify.com/dashboard/applications
 
 ### Installation
 

install.sh

@@ -1,5 +1,9 @@
 #!/bin/bash
 
+MP="`dirname \"$0\"`"           # relative
+MP="`( cd \"$MP\" && pwd )`"    # absolutized and normalized
+cd $MP
+
 if [[ ! $(which python) ]]; then
 	if [[ ! $(which pyenv) ]]; then
 		echo "pyenv installation..."
@@ -12,7 +16,7 @@ if [[ ! $(which python) ]]; then
 	pyenv global 3.9.6
 fi
 
-sudo apt install lame build-essential libffi-dev
+sudo apt install lame build-essential libffi-dev jq curl
 wget -q -O - https://apt.mopidy.com/mopidy.gpg | sudo apt-key add - #add mopidy's libspotify repository
 sudo wget -q -O /etc/apt/sources.list.d/mopidy.list https://apt.mopidy.com/stretch.list   #valid for Debian Stretch.
 sudo apt update && sudo apt install libspotify12 libspotify-dev python-spotify #install libspotify from mopidy's repository

spotify-dl.sh

@@ -1,16 +1,40 @@
 #!/bin/bash
 
+MP="`dirname \"$0\"`"		# relative
+MP="`( cd \"$MP\" && pwd )`"	# absolutized and normalized
+cd $MP
+
 [[ ! $1 ]] && echo "Please give a search" && exit 1
+
+## Get user variables and credentials
 source .env
 mkdir -p "$output"
 
+## Get search or link from arguments
 track=$(echo "$@" | sed 's/ /%20/g ')
 
+## Check if we have a direct spotify link, or search words
 if [[ $(echo "$track" | grep "open.spotify.com") ]]; then
 	link="$track"
 	[[ $(echo "$link" | grep "open.spotify.com/album") ]] && format="{artist} - {album}/{track_name}.{ext}"
 else
+	## Check if we have a non expired token in cache, or get it
+	if [[ -f .token_cache ]]; then
+		cached_timestamp=$(cat .token_cache | jq .expires_time)
+		timestamp=$(date +%s)
+		if [[ $timestamp -lt $cached_timestamp ]]; then
+			sp_token=$(cat .token_cache | jq -r .token)
+		fi
+	fi
+	if [[ ! $sp_token ]]; then
+		base64_id="$(echo -n $sp_client_id:$sp_client_secret | base64 -w 0)"
+		sp_token=$(curl -s --location --request POST 'https://accounts.spotify.com/api/token' --header "Authorization: Basic $base64_id" --data-urlencode 'grant_type=client_credentials' | jq -r .access_token)
+		timestamp=$(date +%s)
+		((timestamp=timestamp+3600))
+		echo -e "{\n\"token\": \"$sp_token\",\n\"expires_time\": $timestamp\n}" | jq . > .token_cache
+	fi
 	link=$(curl -sX "GET" "https://api.spotify.com/v1/search?q=$track&type=track" -H "Accept: application/json" -H "Content-Type: application/json" -H "Authorization: Bearer $sp_token" | jq -r '.[].items[0].external_urls.spotify')
 fi
 
+## Start download
 SPOTIPY_CLIENT_ID="" SPOTIPY_CLIENT_SECRET="" SPOTIPY_REDIRECT_URI="" python lib/spotify_ripper/spotify_ripper/main.py -k .spotify_appkey.key -u "$sp_id" -p "$sp_password" $link -f "$output/$format"