src/main/java/de/b00tload/tools/lastfmtospotifyplaylist/LastFMToSpotify.java

@@ -110,7 +110,9 @@ public class LastFMToSpotify {
                 }
             }
             api.addItemsToPlaylist(list.getId(), adders.toArray(String[]::new)).build().execute();
-            if(configuration.containsKey(configuration.get("playlist.cover"))) api.uploadCustomPlaylistCoverImage(list.getId()).image_data(configuration.get("playlist.cover")).build().execute();
+            if(configuration.containsKey("playlist.cover")){
+                logLn("Check for \"null\" if setting cover was successful: " + api.uploadCustomPlaylistCoverImage(list.getId()).image_data(configuration.get("playlist.cover")).setHeader("User-Agent", configuration.get("requests.useragent")).build().execute(),3);
+            }
             logLn("Done.", 1);
 //        } catch (IOException | ParseException | SpotifyWebApiException e) {
         } catch (Exception e) {

src/main/java/de/b00tload/tools/lastfmtospotifyplaylist/arguments/ArgumentHandler.java

@@ -1,10 +1,16 @@
 package de.b00tload.tools.lastfmtospotifyplaylist.arguments;
 
+import de.b00tload.tools.lastfmtospotifyplaylist.util.FileHelper;
 import de.umass.lastfm.Period;
 import org.jetbrains.annotations.Nullable;
 
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
 import static de.b00tload.tools.lastfmtospotifyplaylist.LastFMToSpotify.LINE_SEPERATOR;
 import static de.b00tload.tools.lastfmtospotifyplaylist.LastFMToSpotify.configuration;
+import static de.b00tload.tools.lastfmtospotifyplaylist.util.Logger.logLn;
 
 public class ArgumentHandler {
 
@@ -21,6 +27,7 @@ public class ArgumentHandler {
             case QUARTERLY -> period(Period.THREE_MONTHS);
             case BIANNUALLY -> period(Period.SIX_MONTHS);
             case YEARLY -> period(Period.TWELVE_MONTHS);
+            case COVER -> cover(value);
         }
     }
 
@@ -111,4 +118,13 @@ public class ArgumentHandler {
     private static void period(Period value) {
         configuration.put("lastfm.period", value.getString());
     }
+
+    private static void cover(String value) {
+        if (value == null || value.equalsIgnoreCase("") || !Files.exists(Path.of(value.replace("\\", "//")))) {
+            System.out.println("--coverart must be provided with a path to a png file. Check usage: " + Arguments.COVER.getUsage());
+            System.exit(500);
+        }
+        String base64 = FileHelper.encodeFileToBase64(new File(value.replace("\\", "//")));
+        configuration.put("playlist.cover", base64);
+    }
 }

src/main/java/de/b00tload/tools/lastfmtospotifyplaylist/arguments/Arguments.java

@@ -33,7 +33,9 @@ public enum Arguments {
     BIANNUALLY("biannually", "[Optional]" + LINE_SEPERATOR
                                         + "Creates a playlist from your top tracks from last half-year.", "--biannualy", "B"),
     YEARLY("yearly", "[Optional]" + LINE_SEPERATOR
-                                        + "Creates a playlist from your top tracks from last year.", "--anually", "A");;
+                                        + "Creates a playlist from your top tracks from last year.", "--anually", "A"),
+    COVER("coverart", "[Optional]" + LINE_SEPERATOR
+                                        + "Will set a cover art for the playlist. Must be jpeg/jpg.", "--coverart <path/to/coverart.jpg>", "ca", "cover");
 
     private final String name;
     private final String description;

src/main/java/de/b00tload/tools/lastfmtospotifyplaylist/util/FileHelper.java

@@ -0,0 +1,23 @@
+package de.b00tload.tools.lastfmtospotifyplaylist.util;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.Base64;
+
+public class FileHelper {
+
+    public static String encodeFileToBase64(File file){
+        String encodedfile = null;
+        try (FileInputStream fileInputStreamReader = new FileInputStream(file)){
+            byte[] bytes = new byte[(int)file.length()];
+            fileInputStreamReader.read(bytes);
+            encodedfile = Base64.getEncoder().encodeToString(bytes);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        return encodedfile;
+    }
+
+}