Grab the music file from your chrome cache.

gsong.py

#!/usr/bin/env python2
#encoding=utf8
#first, you should go some online music website, like xiami, to listen music until the cache download finish. #Then run this command, input the artist name and song name.
import pyid3lib
import glob
import os
#cacheDir= os.environ['HOME'] + '/.cache/google-chrome/Default/Cache/'
cacheDir= os.environ['HOME'] + '/.cache/chromium/Default/Cache/'
#make a list sort by time inversely
fl = sorted(glob.glob(cacheDir + 'f*'), key=lambda f:os.stat(f).st_mtime, reverse=True)
mf=''
for f in fl:
	#find the first one whose size > 1MB
	if os.stat(f).st_size > 1024*1024:
		mf=f
		break;
artistName=raw_input("Please input artist's name:")
songName=raw_input("Please input song's name:")
targetDir=os.environ['HOME'] + "/music/" + artistName;
targetFile=targetDir + "/"  + songName + ".mp3"
print targetDir
print targetFile
os.system("mkdir -p " + targetDir)
os.system("cp " + f + " " + targetFile)
#add Tag
cmd="mid3v2 " + targetFile + " -a " + artistName
os.system("mid3v2 " + targetFile + " -a " + artistName)
os.system("mid3v2 " + targetFile + " -t " + songName)
os.system("mid3v2 " + targetFile)