Saving spotify playlist using HTTP

Hey there,

I am trying to save changes to a spotify playlist over HTTP. All I get when I make a request is null. I am able to create and delete playlists. Here is the JSON that I am sending over. What am I missing?

 {
      "jsonrpc": "2.0",
      "id": "1",
      "method": "core.playlists.save",
      "params": {
        "playlist": 
          {
            "__model__": "Playlist",
            "name": "wtf playlist",
            "uri": "spotify:user:121445141:playlist:4J0X6aMgUoKCRpOp88bJPn",
            "tracks": [
              {
                "album": {
                  "date": "2015",
                  "__model__": "Album",
                  "artists": [
                    {
                      "__model__": "Artist",
                      "name": "Drake",
                      "uri": "spotify:artist:3TVXtAsR1Inumwj472S9r4"
                    }
                  ],
                  "name": "Hotline Bling",
                  "uri": "spotify:album:19YQ10twgD5djBaBDUpH7o"
                },
                "__model__": "Track",
                "name": "Hotline Bling",
                "disc_no": 0,
                "uri": "spotify:track:6nmz4imkDcmtwMjocAzFSx",
                "length": 267000,
                "track_no": 1,
                "artists": [
                  {
                    "__model__": "Artist",
                    "name": "Drake",
                    "uri": "spotify:artist:3TVXtAsR1Inumwj472S9r4"
                  }
                ],
                "date": "2015",
                "bitrate": 160
              },
              {
                "album": {
                  "date": "1975",
                  "__model__": "Album",
                  "artists": [
                    {
                      "__model__": "Artist",
                      "name": "Queen",
                      "uri": "spotify:artist:1dfeR4HaWDbWqFHLkxsg1d"
                    }
                  ],
                  "name": "A Night At The Opera (Deluxe Remastered Version)",
                  "uri": "spotify:album:6X9k3hSsvQck2OfKYdBbXr"
                },
                "__model__": "Track",
                "name": "Bohemian Rhapsody",
                "disc_no": 0,
                "uri": "spotify:track:7tFiyTwD0nx5a1eklYtX2J",
                "length": 354000,
                "track_no": 11,
                "artists": [
                  {
                    "__model__": "Artist",
                    "name": "Queen",
                    "uri": "spotify:artist:1dfeR4HaWDbWqFHLkxsg1d"
                  }
                ],
                "date": "1975",
                "bitrate": 160
              },
              {
                "album": {
                  "date": "1978",
                  "__model__": "Album",
                  "artists": [
                    {
                      "__model__": "Artist",
                      "name": "Queen",
                      "uri": "spotify:artist:1dfeR4HaWDbWqFHLkxsg1d"
                    }
                  ],
                  "name": "Jazz (Deluxe Remastered Version)",
                  "uri": "spotify:album:21HMAUrbbYSj9NiPPlGumy"
                },
                "__model__": "Track",
                "name": "Don't Stop Me Now",
                "disc_no": 0,
                "uri": "spotify:track:7hQJA50XrCWABAu5v6QZ4i",
                "length": 209000,
                "track_no": 12,
                "artists": [
                  {
                    "__model__": "Artist",
                    "name": "Queen",
                    "uri": "spotify:artist:1dfeR4HaWDbWqFHLkxsg1d"
                  }
                ],
                "date": "1978",
                "bitrate": 160
              },
              {
                "album": {
                  "date": "2010",
                  "__model__": "Album",
                  "artists": [
                    {
                      "__model__": "Artist",
                      "name": "Frédéric Chopin",
                      "uri": "spotify:artist:7y97mc3bZRFXzT2szRM4L4"
                    }
                  ],
                  "name": "Chopin: Nocturnes (Volume 1)",
                  "uri": "spotify:album:3RePY8Fh1liHgQQ2X8CjYH"
                },
                "__model__": "Track",
                "name": "Nocturne en mi bémol majeur opus 9 n°2: Ballade en Sol Mineur No.1",
                "disc_no": 0,
                "uri": "spotify:track:7n92QzQomRCLlciO14X0kd",
                "length": 268000,
                "track_no": 1,
                "artists": [
                  {
                    "__model__": "Artist",
                    "name": "Luis Fernando Perez",
                    "uri": "spotify:artist:2MDkMAXgLEGJFogdR000Au"
                  },
                  {
                    "__model__": "Artist",
                    "name": "Frédéric Chopin",
                    "uri": "spotify:artist:7y97mc3bZRFXzT2szRM4L4"
                  }
                ],
                "date": "2010",
                "bitrate": 160
              }
            ]
          }
        
      }
    }

It looks like Mopidy can save other playlists, just not Spotify playlists.

mopidy-spotify doesn’t have playlist editing support just yet as far as I can remember.