通过 Mpris 接口 `Metadata::xesam:asText` 提供歌词 about netease-cloud-music-gtk

[gmg137]

没有使用mpris的歌词接口是为了减少网络请求次数，将歌词缓存在本地，当再次需要时可以直接从本地读取。缓存lrc和使用asText功能上是重复的，如果只实现一个的话缓存lrc性价比会更高一些。

[tuberry]

上面的 patch 只是在更新 PlayListLyricsPage 的歌词时顺便更一下 Mpris，获取歌词的方式根本没变。更新 Mpris 也需要网络请求吗？

[gmg137]

我的意思是，更新Mpris歌词与缓存歌词文件在目的上是重复的，如果二选一选择mpris的asText传送歌词，会造成每次都要请求网络。

另外如果只在打开播放列表页面时才触发更新mpris歌词，这样该操作是没有意义的。

[tuberry]

另外如果只在打开播放列表页面时才触发更新mpris歌词，这样该操作是没有意义的。

在打开判定之前更新的。

这里启用桌面歌词支持时每次都会下载/读取本地歌词，顺便更新一下 Mpris 不好吗？读了不能传，要传不能存（读），苦涩的选择。目前如果本地有文件，扩展那边要多读一次，否则就多一次注定失败的网络请求，也算重复吧。既然如此，你可能要按需读取。

谢谢回答。

[tuberry]

另外发现在这每250ms更新进度条时 Mpris 会发Seeked信号，同时更新Mpris::Position。这似乎都没有必要。

建议在自动更新进度条时不要发Seeked，至于Position之前就建议参考Lollypop按需直接从Gst.Player读取不用更新。

谢谢。

[gmg137]

如果不更新 position 你的歌词插件该如何确定当前播放位置? 特别是反复前后拖拉进度条后，会不会有影响。
你说的按需直接从Gst.Player读取我没太明白，这里是谁来读取?

更新 seeked 是为了让别的 mpris 播放插件同步播放条进度。

我上次测试gnome-music 在反复前后拖拉进度条时好像会卡住，具体情况忘了，反正就是做了取舍才弄成现在这样。

最近在忙装修，可以把你的建议先说下，我等闲了再研究研究看怎么弄。

[tuberry]

如果不更新 position 你的歌词插件该如何确定当前播放位置? 特别是反复前后拖拉进度条后，会不会有影响。

客户端维护有 timer，获取当前 position 一般为初始化而非同步。拖动进度条结束发一次Seeked就行，客户端不关心怎么拖的。

你说的按需直接从Gst.Player读取我没太明白，这里是谁来读取?

服务端Position不像Volume之类的会同步到客户端，客户端通过 org.freedesktop.DBus.Properties.Get 接口来获取 Position，所以服务端在实现此接口时，对Position直接返回 Gst.Player 的位置即可，而非定期set_position缓存一个随时过期的值待用。

我上次测试gnome-music 在反复前后拖拉进度条时好像会卡住，具体情况忘了，反正就是做了取舍才弄成现在这样。

gnome-music 的实现有问题，表现为拖动过程中 PlaybackStatus 在 Playing 和 Paused 间反复横跳，与客户端无关。

更新 seeked 是为了让别的 mpris 播放插件同步播放条进度。

这听起来有点像某软件每秒截30次屏来实现屏幕共享。尤其结合上文，为某进度条每250ms发一次信号，却不愿为歌词更一次元数据，就显得很有意思:) 总之，这信号据说 indicates that the track position has changed in a way that is inconsistant with the current playing state，用于同步不失为另辟蹊径吧。

最近在忙装修，可以把你的建议先说下，我等闲了再研究研究看怎么弄。

祝好。建议先前有一些了，刚打开播放列表没找到移除歌曲的办法，不确定这是 Feature 还是 Bug。

就这样吧。

[gmg137]

你好，我在尝试使用 asText 提供歌词时，desktop-lyrics 没有正常工作，问题如下：

1、播放歌曲时，在使用asText推送歌词的情况下，desktop-lyrics 依然会自动下载歌词，测试应该是没有使用我用asText提供的歌词;

2、当播放下面的歌曲时，没有任何反应，也没有自动下载歌词。

https://music.163.com/song?id=2021437775
歌曲:My Stupid Heart (Kids Version)
歌手:Walk off the Earth

歌词如下(已测试去掉换行符问题依旧)：

"[00:00.000] 作曲 : Gianni Luminati Nicassio/Jake Torrey/Lostboy/Michael Matosic/Sarah Blackwood/Tokyo Speirs\n[00:00.112]Hey, everybody\n[00:00.514]My mom 'n dad made this new song called \"My Stupid Heart\"\n[00:03.547]I'm gonna play it with my brothers\n[00:05.187]Let's gooooooo!!\n[00:07.074]\n[00:07.337]My stupid heart\n[00:08.881]Don't know\n[00:09.983]I've tried to let you go\n[00:11.850]So many times before\n[00:13.938]Then wound up at your door\n[00:15.765]My stupid\n[00:16.149]\n[00:16.524]Can't believe that I haven't figured out by now\n[00:19.634]Every time I call you up\n[00:21.842]All you do is let me down (Let's Go!)\n[00:24.487]\n[00:24.833]Shoulda known there was nothing about us I could change\n[00:28.105]Everytime we try to be friends\n[00:30.112]It always ends the same\n[00:32.207]\n[00:32.368]But when I try to remember\n[00:36.376]All the pain that we've been through\n[00:40.596]Something in me says whatever\n[00:44.781]And it brings me back to you\n[00:48.172]\n[00:48.869]My stupid heart\n[00:50.638]Don't know\n[00:51.631]I've tried to let you go\n[00:53.583]So many times before\n[00:55.604]Then wound up at your door\n[00:57.482]My stupid heart\n[00:58.854]Too late\n[00:59.796]Already on my way\n[01:01.920]If we go down in flames\n[01:04.123]Again then you can blame my stupid heart\n[01:09.832](Okay!)\n[01:11.917](Okay!)\n[01:13.068]You can blame my stupid heart\n[01:18.386](Okay!)\n[01:20.658](Okay!)\n[01:21.279]You can blame my stupid heart\n[01:23.518]\n[01:23.737]Every now and then I get inside my head\n[01:26.555]Try to leave your text unread\n[01:28.357]But I wind up here instead\n[01:30.968]\n[01:31.676]I shoulda bit my tongue while we were still ahead\n[01:34.787]Yeah always had to be right\n[01:36.800]Til we had nothing left\n[01:39.079]\n[01:39.238]But when I try to remember\n[01:43.129]All the pain that we've been through\n[01:47.364]Something in me says whatever\n[01:51.615]And it brings me back to you\n[01:55.052]\n[01:55.613]My stupid heart\n[01:57.328]Don't know\n[01:58.440]I've tried to let you go\n[02:00.248]So many times before\n[02:02.418]Then wound up at your door\n[02:04.002]My stupid heart\n[02:05.665]Too late\n[02:06.822]Already on my way\n[02:08.590]If we go down in flames\n[02:10.830]Again then you can blame my stupid heart (Let's Go!)\n[02:16.703](Okay!)\n[02:18.945](Okay!)\n[02:19.437]\n[02:19.607]You can blame my stupid heart\n[02:23.868]I've tried to let you go\n[02:25.389]So many times before\n[02:29.064]You can blame my stupid heart\n[02:30.832]Too late\n[02:32.142]Already on my way\n[02:33.964]If we go down in flames\n[02:35.902]Again then you can blame my stupid heart\n[02:39.253]Too late\n[02:40.317]Already on my way\n[02:42.139]If we go down in flames\n[02:44.276]Again then you can blame my stupid heart"

[tuberry]

GNOME45及以后的版本才支持，如果版本没问题看看Metadata是否提供了歌词：

gdbus call --session --dest org.mpris.MediaPlayer2.NeteaseCloudMusicGtk4 --object-path /org/mpris/MediaPlayer2 --method org.freedesktop.DBus.Properties.Get org.mpris.MediaPlayer2.Player Metadata

另外无asText字段时会尝试下载，所以初始化暂无歌词时需设置asText为空（字符串），有歌词再更新即可。

[gmg137]

GNOME 版本是 45.3, Metadata 中可以正常获取歌词：
(<{'mpris:artUrl': <'file:///home/gmg/.cache/netease-cloud-music-gtk4/159843058-songlist.jpg'>, 'mpris:length': <int64 168112000>, 'mpris:trackid': <objectpath '/com/gitee/gmg137/NeteaseCloudMusicGtk4/2021437775'>, 'xesam:album': <'My Stupid Heart (Kids Version)'>, 'xesam:artist': <['Walk off the Earth']>, 'xesam:asText': <"[00:00.000] 作词 : Kim Taylor\n[00:00.000] 作曲 : Kim Taylor\n[00:00.000]La di da di da da\n[00:03.860]La di da di da da\n[00:08.110]La di da di da da\n[00:12.000]La da da\n[00:14.760]\n[00:16.510]I am tied by truth like an anchor\n[00:25.440]Anchored to a bottomless sea\n[00:32.340]I am floating freely in the heavens\n[00:41.440]Held in by your heart's gravity\n[00:46.160]\n[00:48.920]All because of love\n[00:53.040]All because of love\n[00:57.410]Even though sometimes\n[00:59.999]You don't know who I am\n[01:03.259]\n[01:05.239]I am you..\n[01:09.290]Everything you do\n[01:13.168]Anything you say,\n[01:17.319]You want me to be\n[01:21.328]You and me..\n[01:25.290]We're charms on a chain\n[01:29.790]Linked eternally one we can't undo\n[01:37.110]And I am you\n[01:40.790]\n[01:41.890]La di da di da da\n[01:45.840]La di da di da da\n[01:49.799]La da da\n[01:52.099]\n[01:53.920]All my senses awaken to the changes yeah\n[02:02.209]And I feel alive inside my own skin\n[02:10.159]All my reasons tell me just how strange it is\n[02:18.409]Coming home to a place I've always been\n[02:24.199]\n[02:26.439]And it's all for love\n[02:30.530]And it's all for love\n[02:34.739]Even though sometimes,\n[02:37.429]I don't know who I am\n[02:40.639]\n[02:42.629]I am you..\n[02:46.699]Everything you do\n[02:50.360]Anything you say,\n[02:54.549]You want me to be\n[02:58.810]You and me..\n[03:02.739]We're charms on a chain\n[03:07.109]Linked eternally one we can't undo, ohhh\n[03:14.829]I am you...\n[03:18.979]La di da di da da\n[03:22.869]La di da di da da (anything you say)\n[03:27.069]La da da (everything you do)\n[03:30.970]La di da di da da (I am you...)\n[03:35.129]La di da di da da\n[03:39.169]La di da di da da (anything you say)\n[03:43.160]La da da (everything you do)\n[03:47.209]I am you... (La di da di da da)\n[03:51.190]I am you... (La di da di da da)\n[03:55.119]I am you... (La di da di da da)\n[03:59.049]I am you... (La di da di da da)\n[04:01.639]\n[04:03.199]I am you... (La di da di da da)\n[04:07.139]I am you... (La di da di da da)\n[04:11.379]Everything you do....\n[04:18.069]\n[04:20.459]Fading away...\n[04:28.379]">, 'xesam:title': <'My Stupid Heart (Kids Version)'>}>,)

下面是我编译好的程序你可以测试下，如果不能运行我再把源代码打包了发你。
netease-cloud-music-gtk4.zip

[tuberry]

用此提交（对应扩展网站上的版本19）在GNOME46上测试发现你编译的 grsource 文件路径硬编码为本地，不过我用软连接解决了。
随机播放歌曲均显示为你上方提供的歌词，扩展本身并未下载/保存任何文件：

[gmg137]

已经可以正常显示了，不过osdlyrics 貌似不支持 xesam:asText 接口，这样的话还是要保留从歌词文件读取歌词的功能。