feat: api endpoint to get playlist properties

Iterative approach. Currently only lists mp3 files.

software/src/app.py

@@ -193,3 +193,6 @@ class PlayerApp:
 
     def get_nfc(self):
         return self.nfc
+
+    def get_playlist_db(self):
+        return self.playlist_db

software/src/utils/playlistdb.py

@@ -251,6 +251,16 @@ class BTreeDB(IPlaylistDB):
         if flush:
             self._flush()
 
+    def getPlaylistTags(self):
+        """
+        Get a keys-only dict of all defined playlists. Playlists currently do not have names, but are identified by
+        their tag.
+        """
+        playlist_tags = set()
+        for item in self.db:
+            playlist_tags.add(item.split(b'/')[0])
+        return playlist_tags
+
     def getPlaylistForTag(self, tag: bytes):
         """
         Lookup the playlist for 'tag' and return the Playlist object. Return None if no playlist exists for the given

software/src/webserver.py

@@ -4,6 +4,8 @@ Copyright (c) 2024-2025 Stefan Kratochwil <Kratochwil-LA@gmx.de>
 '''
 
 import asyncio
+import json
+import os
 
 from microdot import Microdot
 
@@ -12,14 +14,15 @@ server = None
 config = None
 app = None
 nfc = None
-
+playlist_db = None
 
 def start_webserver(config_, app_):
-    global server, config, app, nfc
+    global server, config, app, nfc, playlist_db
     server = asyncio.create_task(webapp.start_server(port=80))
     config = config_
     app = app_
     nfc = app.get_nfc()
+    playlist_db = app.get_playlist_db()
 
 
 @webapp.before_request
@@ -72,3 +75,50 @@ async def config_put(request):
 async def last_tag_uid_get(request):
     tag, _ = nfc.get_last_uid()
     return {'tag': tag}
+
+
+@webapp.route('/api/v1/playlists', methods=['GET'])
+async def playlists_get(request):
+    return sorted(playlist_db.getPlaylistTags())
+
+
+def is_hex(s):
+    hex_chars = '0123456789abcdef'
+    return all(c in hex_chars for c in s)
+
+
+fsroot = b'/sd'
+
+
+@webapp.route('/api/v1/playlist/<tag>', methods=['GET'])
+async def playlist_get(request, tag):
+    if not is_hex(tag):
+        return 'invalid tag', 400
+
+    playlist = playlist_db.getPlaylistForTag(tag.encode())
+
+    return {
+            'shuffle': playlist.__dict__.get('shuffle'),
+            'persist': playlist.__dict__.get('persist'),
+            'paths': [(p[len(fsroot):] if p.startswith(fsroot) else p).decode()
+                      for p in playlist.getPaths()],
+    }
+
+@webapp.route('/api/v1/audiofiles', methods=['GET'])
+async def audiofiles_get(request):
+    audiofiles = set()
+    dirstack = [fsroot]
+
+    while dirstack:
+        current_dir = dirstack.pop()
+        for entry in os.ilistdir(current_dir):
+            name = entry[0]
+            type_ = entry[1]
+            current_path = current_dir + '/' + name
+            if type_ == 0x4000:
+                dirstack.append(current_path)
+            elif type_ == 0x8000:
+                if name.lower().endswith('.mp3'):
+                    audiofiles.add(current_path[len(fsroot):])
+
+    return sorted(audiofiles)