Amazon Prime Music Download Bookmarklet

amznMusic.js

javascript:(() => {
    function download(uid) {
        var url = "";
        var metadata = null;
        
        return new Promise((resolve, reject) => {
            amznMusic.data.getServerSongForPlayer(result => {
                if (!result) {
                    reject();
                    return;
                }
                
                metadata = result.metadata;
                resolve();
            }, { objectId: uid });
        }).then(() => {
            return new Promise((resolve, reject) => {
                amznMusic.dmls.getStreamUrlByAsin(metadata.asin).then(result => {
                    url = result;
                    resolve();
                }, err => {
                    reject(err);
                });
            });
        }).then(() => {
            var filename = metadata.name.replace(/\..+?$/, ".m4a").replace(/"/g, "\\\"");
            
            var objMeta = {
                title: metadata.title,
                author: metadata.artistName,
                album_artist: metadata.albumArtistName,
                album: metadata.albumName,
                track: metadata.trackNum,
                genre: metadata.primaryGenre
            };
            
            var strMeta = Object.keys(objMeta).map(key => {
                return `-metadata ${key}="${objMeta[key].replace(/"/g, "\\\"")}"`;
            }).join(" ");
            
            
            prompt(metadata.title, `ffmpeg -i "${url}" -acodec copy -bsf aac_adtstoasc ${strMeta} "${filename}"`);
        });
    }
    
    var list = Array.from(document.querySelectorAll(".selectable"));
    
    list.forEach(elem => {
        var uid = elem.getAttribute("uid");
        
        var td = document.createElement("td");
        var a = document.createElement("a");
        
        a.textContent = "DL";
        a.addEventListener("click", () => {
            download(uid);
        });
        
        td.appendChild(a);
        elem.appendChild(td);
    });
})();