Fix a lot of error handling issues and other code cleanup

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	spotifydl "github.com/BharatKalluri/spotifydl/src"
 	"github.com/spf13/cobra"
@@ -11,17 +12,38 @@ import (
 func main() {
 	var playlistid string
 	var albumid string
+	var spotifyURL string
 
 	var rootCmd = &cobra.Command{
 		Use:   "spotifydl",
 		Short: "spotifydl is a awesome music downloader",
-		Long: `Spotifydl lets you download albums and playlists and tags them for you
+		Long: `Spotifydl lets you download albums and playlists and tags them for you.
 Pass Either album ID or Playlist ID to start downloading`,
 		Run: func(cmd *cobra.Command, args []string) {
-			if len(playlistid) > 0 && len(albumid) > 0 {
-				fmt.Println("Either album ID or playlist ID")
-				cmd.Help()
-			} else if len(albumid) > 0 {
+
+			if len(spotifyURL) > 0 {
+				splitURL := strings.Split(spotifyURL, "/")
+
+				if len(splitURL) < 2 {
+					fmt.Println("Please enter the url copied from the spotify client")
+					os.Exit(1)
+				}
+
+				spotifyID := splitURL[len(splitURL)-1]
+				if strings.Contains(spotifyID, "?") {
+					fmt.Println("Please remove the part of the url after the question mark (?) and try again")
+					fmt.Println("For example, https://open.spotify.com/playlist/randomID?si=otherRandomID should just be https://open.spotify.com/playlist/randomID ")
+					os.Exit(1)
+				}
+
+				if strings.Contains(spotifyURL, "album") {
+					albumid = spotifyID
+				} else if strings.Contains(spotifyURL, "playlist") {
+					playlistid = spotifyID
+				}
+			}
+
+			if len(albumid) > 0 {
 				// Download album with the given album ID
 				spotifydl.DownloadAlbum(albumid)
 			} else if len(playlistid) > 0 {
@@ -36,6 +58,7 @@ Pass Either album ID or Playlist ID to start downloading`,
 
 	rootCmd.Flags().StringVarP(&playlistid, "playlistid", "p", "", "Album ID found on spotify")
 	rootCmd.Flags().StringVarP(&albumid, "albumid", "a", "", "Album ID found on spotify")
+	rootCmd.Flags().StringVarP(&spotifyURL, "spotifyurl", "u", "", "URL copied on spotify")
 
 	if err := rootCmd.Execute(); err != nil {
 		fmt.Println(err)

src/downloader.go

@@ -2,6 +2,7 @@ package spotifydl
 
 import (
 	"fmt"
+	"os"
 	"os/exec"
 
 	"github.com/zmb3/spotify"
@@ -17,7 +18,10 @@ func Downloader(url string, track spotify.FullTrack) {
 		"-o", track.Name+".%(ext)s", "--audio-quality", "0", url)
 	_, err := ytdlCmd.Output()
 	if err != nil {
-		panic(err)
+		fmt.Println("=> An error occured while trying to download using youtube-dl")
+		fmt.Println("Make sure you have youtube-dl and ffmpeg installed on this system. This was the command we tried to run:")
+		fmt.Println(ytdlCmd.String())
+		os.Exit(1)
 	}
 
 	// Tag the file with metadata

src/start.go

@@ -2,6 +2,7 @@ package spotifydl
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/zmb3/spotify"
 )
@@ -13,8 +14,11 @@ func DownloadPlaylist(pid string) {
 		UserClient: user,
 	}
 	playlistID := spotify.ID(pid)
-	// TODO: Exit gracefully if the playlist is not found
-	trackListJSON, _ := cli.UserClient.GetPlaylistTracks(playlistID)
+	trackListJSON, err := cli.UserClient.GetPlaylistTracks(playlistID)
+	if err != nil {
+		fmt.Println("Playlist not found!")
+		os.Exit(1)
+	}
 	for _, val := range trackListJSON.Tracks {
 		cli.TrackList = append(cli.TrackList, val.Track)
 	}
@@ -28,8 +32,11 @@ func DownloadAlbum(aid string) {
 		UserClient: user,
 	}
 	albumid := spotify.ID(aid)
-	// TODO: Exit gracefully if album is not found
-	album, _ := user.GetAlbum(albumid)
+	album, err := user.GetAlbum(albumid)
+	if err != nil {
+		fmt.Println("Album not found!")
+		os.Exit(1)
+	}
 	for _, val := range album.Tracks.Tracks {
 		cli.TrackList = append(cli.TrackList, spotify.FullTrack{
 			SimpleTrack: val,

src/utils/generic_utils.go

@@ -1,17 +1,22 @@
 package utils
 
 import (
+	"fmt"
 	"io/ioutil"
 	"net/http"
 )
 
 // DownloadFile will get a url and return bytes
-func DownloadFile(url string) []byte {
+func DownloadFile(url string) ([]byte, error) {
 	resp, err := http.Get(url)
 	if err != nil {
 		panic(err)
 	}
 	defer resp.Body.Close()
-	buffer, _ := ioutil.ReadAll(resp.Body)
-	return buffer
+	buffer, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		fmt.Println("Failed to download album art!")
+		return nil, err
+	}
+	return buffer, nil
 }

src/utils/tagger.go

@@ -21,9 +21,7 @@ func TagFileWithSpotifyMetadata(fileName string, trackData spotify.FullTrack) {
 	artistTag := strings.Join(trackArtist[:], ",")
 	dateObject, _ := time.Parse("2006-01-02", trackData.Album.ReleaseDate)
 	yearTag := dateObject.Year()
-	// TODO: Check images is not null
-	albumArtURL := trackData.Album.Images[0].URL
-	albumArt := DownloadFile(albumArtURL)
+	albumArtImages := trackData.Album.Images
 
 	mp3File, err := id3v2.Open(fileName, id3v2.Options{Parse: true})
 	if err != nil {
@@ -35,14 +33,21 @@ func TagFileWithSpotifyMetadata(fileName string, trackData spotify.FullTrack) {
 	mp3File.SetArtist(artistTag)
 	mp3File.SetAlbum(albumTag)
 	mp3File.SetYear(strconv.Itoa(yearTag))
-	pic := id3v2.PictureFrame{
-		Encoding:    id3v2.EncodingUTF8,
-		MimeType:    "image/jpeg",
-		PictureType: id3v2.PTFrontCover,
-		Description: "Front cover",
-		Picture:     albumArt,
+
+	if len(albumArtImages) > 0 {
+		albumArtURL := albumArtImages[0].URL
+		albumArt, albumArtDownloadErr := DownloadFile(albumArtURL)
+		if albumArtDownloadErr != nil {
+			pic := id3v2.PictureFrame{
+				Encoding:    id3v2.EncodingUTF8,
+				MimeType:    "image/jpeg",
+				PictureType: id3v2.PTFrontCover,
+				Description: "Front cover",
+				Picture:     albumArt,
+			}
+			mp3File.AddAttachedPicture(pic)
+		}
 	}
-	mp3File.AddAttachedPicture(pic)
 
 	if err = mp3File.Save(); err != nil {
 		log.Fatal("Error while saving a tag: ", err)