Add fetching lyrics in the JSON api

docs/json-api.md

@@ -798,6 +798,7 @@ curl -X PUT "http://localhost:3689/api/queue/items/2"
 | GET       | [/api/library/tracks/{id}/playlists](#list-playlists-for-a-track) | Get list of playlists for a track |
 | PUT       | [/api/library/tracks](#update-track-properties)             | Update multiple track properties     |
 | PUT       | [/api/library/tracks/{id}](#update-track-properties)        | Update single track properties       |
+| GET       | [/api/library/lyrics/{id}](#get-lyrics-for-track)           | Fetch lyrics for a track             |
 | GET       | [/api/library/genres](#list-genres)                         | Get list of genres                   |
 | GET       | [/api/library/count](#get-count-of-tracks-artists-and-albums) | Get count of tracks, artists and albums |
 | GET       | [/api/library/files](#list-local-directories)               | Get list of directories in the local library    |
@@ -1544,10 +1545,47 @@ curl -X GET "http://localhost:3689/api/library/tracks/1"
   "data_kind": "file",
   "path": "/music/srv/Incubus/Make Yourself/12 Pardon Me.mp3",
   "uri": "library:track:1",
-  "artwork_url": "/artwork/item/1"
+  "artwork_url": "/artwork/item/1",
+  "lyrics": 1
 }
 ```
 
+### Get lyrics for track
+
+Get lyrics for a specific track in your library
+
+**Endpoint**
+
+```http
+GET /api/library/lyrics/{id}
+```
+
+**Path parameters**
+
+| Parameter       | Value                |
+| --------------- | -------------------- |
+| id              | Track id             |
+
+**Response**
+
+On success returns the HTTP `200 OK` success status response code. With the response body holding the **[`lyrics`](#lyrics-object) object**.
+
+
+**Example**
+
+```shell
+curl -X GET "http://localhost:3689/api/library/lyrics/1"
+```
+
+```json
+{
+  "lyrics": "[00:01:12] Pardon Me 
+             [00:01:14] Oh now",
+  "length_ms": 223170,
+}
+```
+
+
 
 ### List playlists for a track
 
@@ -2624,6 +2662,14 @@ curl --include \
 | usermark           | integer  | User review marking of track (ranges from 0) |
 
 
+### `lyrics` object
+
+| Key                | Type     | Value                                     |
+| ------------------ | -------- | ----------------------------------------- |
+| lyrics             | string   | Lyrics in LRC or plain text               |
+| length_ms          | integer  | Track length in milliseconds              |
+
+
 ### `paging` object
 
 | Key             | Type     | Value                                     |

src/db.c

@@ -230,6 +230,7 @@ static const struct col_type_map mfi_cols_map[] =
     { "channels",           mfi_offsetof(channels),           DB_TYPE_INT },
     { "usermark",           mfi_offsetof(usermark),           DB_TYPE_INT },
     { "scan_kind",          mfi_offsetof(scan_kind),          DB_TYPE_INT },
+    { "lyrics",             mfi_offsetof(lyrics),             DB_TYPE_STRING },
   };
 
 /* This list must be kept in sync with
@@ -371,6 +372,7 @@ static const ssize_t dbmfi_cols_map[] =
     dbmfi_offsetof(channels),
     dbmfi_offsetof(usermark),
     dbmfi_offsetof(scan_kind),
+    dbmfi_offsetof(lyrics),
   };
 
 /* This list must be kept in sync with

src/db.h

@@ -423,6 +423,7 @@ struct db_media_file_info {
   char *channels;
   char *usermark;
   char *scan_kind;
+  char *lyrics;
 };
 
 #define dbmfi_offsetof(field) offsetof(struct db_media_file_info, field)

src/httpd_jsonapi.c

@@ -83,6 +83,13 @@ safe_json_add_string(json_object *obj, const char *key, const char *value)
     json_object_object_add(obj, key, json_object_new_string(value));
 }
 
+static inline void
+safe_json_add_int(json_object *obj, const char *key, int value)
+{
+  json_object_object_add(obj, key, json_object_new_int(value));
+}
+
+
 static inline void
 safe_json_add_string_from_int64(json_object *obj, const char *key, int64_t value)
 {
@@ -322,17 +329,35 @@ track_to_json(struct db_media_file_info *dbmfi)
 
   safe_json_add_string(item, "path", dbmfi->path);
 
-  ret = snprintf(uri, sizeof(uri), "%s:%s:%s", "library", "track", dbmfi->id);
+  ret = snprintf(uri, sizeof(uri), "library:track:%s", dbmfi->id);
   if (ret < sizeof(uri))
     json_object_object_add(item, "uri", json_object_new_string(uri));
 
   ret = snprintf(artwork_url, sizeof(artwork_url), "/artwork/item/%s", dbmfi->id);
   if (ret < sizeof(artwork_url))
     json_object_object_add(item, "artwork_url", json_object_new_string(artwork_url));
 
+  if (dbmfi->lyrics != NULL)
+    safe_json_add_int(item, "lyrics", 1);
   return item;
 }
 
+static json_object *
+lyrics_to_json(struct db_media_file_info *dbmfi)
+{
+  json_object *item;
+
+  item = json_object_new_object();
+
+  if (dbmfi->lyrics != NULL)
+    {
+      safe_json_add_string(item, "lyrics", dbmfi->lyrics);
+      safe_json_add_int_from_string(item, "length_ms", dbmfi->song_length);
+    }
+  return item;
+}
+
+
 // TODO Only partially implemented. A full implementation should use a mapping
 // table, which should also be used above in track_to_json(). It should also
 // return errors if there are incorrect/mispelled fields, but not sure how to
@@ -3311,6 +3336,59 @@ jsonapi_reply_library_tracks_get_byid(struct httpd_request *hreq)
   return HTTP_OK;
 }
 
+static int
+jsonapi_reply_library_lyrics_get_byid(struct httpd_request *hreq)
+{
+  struct query_params query_params;
+  const char *track_id;
+  struct db_media_file_info dbmfi;
+  json_object *reply = NULL;
+  int ret = 0;
+  bool notfound = false;
+
+  if (!is_modified(hreq, DB_ADMIN_DB_MODIFIED))
+    return HTTP_NOTMODIFIED;
+
+  track_id = hreq->path_parts[3];
+
+  memset(&query_params, 0, sizeof(struct query_params));
+
+  query_params.type = Q_ITEMS;
+  query_params.filter = db_mprintf("(f.id = %q)", track_id);
+
+  ret = db_query_start(&query_params);
+  if (ret < 0)
+    goto error;
+
+  ret = db_query_fetch_file(&dbmfi, &query_params);
+  if (ret < 0)
+    goto error;
+  else if (ret == 1)
+    {
+      DPRINTF(E_LOG, L_WEB, "Track with id '%s' not found.\n", track_id);
+      ret = -1;
+      notfound = true;
+      goto error;
+    }
+
+  reply = lyrics_to_json(&dbmfi);
+
+  ret = evbuffer_add_printf(hreq->out_body, "%s", json_object_to_json_string(reply));
+  if (ret < 0)
+    DPRINTF(E_LOG, L_WEB, "browse: Couldn't add track to response buffer.\n");
+
+ error:
+  db_query_end(&query_params);
+  free(query_params.filter);
+  jparse_free(reply);
+
+  if (ret < 0)
+    return notfound ? HTTP_NOTFOUND : HTTP_INTERNAL;
+
+  return HTTP_OK;
+}
+
+
 static int
 jsonapi_reply_library_tracks_put(struct httpd_request *hreq)
 {
@@ -4688,6 +4766,7 @@ static struct httpd_uri_map adm_handlers[] =
     { HTTPD_METHOD_GET,    "^/api/library/tracks/[[:digit:]]+/playlists$", jsonapi_reply_library_track_playlists },
     { HTTPD_METHOD_GET,    "^/api/library/(genres|composers)$",            jsonapi_reply_library_browse },
     { HTTPD_METHOD_GET,    "^/api/library/(genres|composers)/.*$",         jsonapi_reply_library_browseitem },
+    { HTTPD_METHOD_GET,    "^/api/library/lyrics/[[:digit:]]+$",           jsonapi_reply_library_lyrics_get_byid },
     { HTTPD_METHOD_GET,    "^/api/library/count$",                         jsonapi_reply_library_count },
     { HTTPD_METHOD_GET,    "^/api/library/files$",                         jsonapi_reply_library_files },
     { HTTPD_METHOD_POST,   "^/api/library/add$",                           jsonapi_reply_library_add },