Using urllib.urlretrieve to download files over HTTP not working

Question

I'm still working on my mp3 downloader but now I'm having trouble with the files being downloaded. I have two versions of the part that's tripping me up. The first gives me a proper file but causes an error. The second gives me a file that is way too small but no error. I've tried opening the file in binary mode but that didn't help. I'm pretty new to doing any work with html so any help would be apprecitaed.

import urllib
import urllib2

def milk():
    SongList = []
    SongStrings = []
    SongNames = []
    earmilk = urllib.urlopen("http://www.earmilk.com/category/pop")
    reader = earmilk.read()
    #gets the position of the playlist
    PlaylistPos = reader.find("var newPlaylistTracks = ")
    #finds the number of songs in the playlist
    NumberSongs = reader[reader.find("var newPlaylistIds = " ): PlaylistPos].count(",") + 1
    initPos = PlaylistPos

    #goes though the playlist and records the html address and name of the song

    for song in range(0, NumberSongs):
        songPos = reader[initPos:].find("http:") + initPos
        namePos = reader[songPos:].find("name") + songPos
        namePos += reader[namePos:].find(">")
        nameEndPos = reader[namePos:].find("<") + namePos
        SongStrings.append(reader[songPos: reader[songPos:].find('"') + songPos])
        SongNames.append(reader[namePos + 1: nameEndPos])
        initPos = nameEndPos

    for correction in range(0, NumberSongs):
        SongStrings[correction] = SongStrings[correction].replace('\\/', "/")

    #downloading songs

    fileName = ''.join([a.isalnum() and a or '_' for a in SongNames[0]])
    fileName = fileName.replace("_", " ") + ".mp3"


#         This version writes a file that can be played but gives an error saying: "TypeError: expected a character buffer object"
##    songDL = open(fileName, "wb")
##    songDL.write(urllib.urlretrieve(SongStrings[0], fileName))


#         This version creates the file but it cannot be played (file size is much smaller than it should be)
##    url = urllib.urlretrieve(SongStrings[0], fileName)
##    url = str(url)
##    songDL = open(fileName, "wb")
##    songDL.write(url)


    songDL.close()

    earmilk.close()

Answer 1

Re-read the documentation for urllib.urlretrieve:

Return a tuple (filename, headers) where filename is the local file name under which the object can be found, and headers is whatever the info() method of the object returned by urlopen() returned (for a remote object, possibly cached).

You appear to be expecting it to return the bytes of the file itself. The point of urlretrieve is that it handles writing to a file for you, and returns the filename it was written to (which will generally be the same thing as your second argument to the function if you provided one).