Mt. Molelog

DAAP notes mark 1

As you know Bob, Apple today introduced iTunes 4, with two significant enhancements: Music Sharing via Rendezvous, and an online Music Store.

I suspect lots of people will be looking at how the store works, to enable non-Maccies to take advantage of it, but I want to look at the Music Sharing first.

My iBook is still unhappy, but Ken was kind enough to send me some dumps to look over.

Discovery is via zeroconf/mDNS/Rendezvous queries for the _daap._tcp service. After that, communication is via the DAAP on TCP port 3689. DAAP is essentially HTTP.

A typical request header looks like

GET /server-info HTTP/1.1
Host: 10.0.1.7
Accept: */*
User-Agent: iTunes/4.0 (Macintosh; N; PPC)
Client-DAAP-Version: 1.0
Accept-Encoding: gzip

with the matching response

HTTP/1.1 200 OK
Date: Tue, 29 Apr 2003 04:02:29 GMT
DAAP-Server: iTunes/4.0 (Mac OS X)
Content-Type: application/x-dmap-tagged
Content-Length: 118
Content-Encoding: gzip

Some things to note it sure looks like HTTP; until the actual streaming, all the responses are Content-Type application/x-dmap-tagged and Content-Encoded gzip; "dmap" will appear later also. There's a DMAP that's the DECT Multimedia Access Profile that's at least in the same ballpark, but doesn't seem to be related.

The x-dmap-tagged data looks a lot like the iPod/iTunes database format, unsurprisingly.

The actual pre-streaming requests are

• /server-info
• /content-codes
• /login
• /update?session-id=4409&revision-number=1
• /databases?session-id=4409&revision-number=3
• /databases/32/items?type=music&meta=dmap.itemid, dmap.itemname, dmap.itemkind, dmap.persistentid, daap.songalbum, daap.songartist, daap.songbitrate, daap.songbeatsperminute, daap.songcomment, daap.songcompilation, daap.songcomposer, daap.songdateadded, daap.songdatemodified, daap.songdisccount, daap.songdiscnumber, daap.songdisabled, daap.songeqpreset, daap.songformat, daap.songgenre, daap.songdescription, daap.songrelativevolume, daap.songsamplerap.songsize, daap.songstarttime, daap.songstoptime, daap.songtime, daap.songtrackcount, daap.songtracknumber, daap.songuserrating, daap.songyear, daap.songdatakind, daap.songdataurl, com.apple.itunes.norm-volume&session-id=4409&revision-number=3
• /databases/32/containers?meta=dmap.itemid, dmap.itemname, dmap.persistentid, com.apple.itunes.smart-playlist&session-id=4409&revision-number=3
• /databases/32/containers/1861/items?type=music&meta=dmap.itemkind, dmap.itemid, dmap.containeritemid&session-id=4409&revision-number=3
• /databases/32/containers/3692/items?type=music&meta=dmap.itemkind, dmap.itemid, dmap.containeritemid&session-id=4409&revision-number=3
• /databases/32/containers/3894/items?type=music&meta=dmap.itemkind, dmap.itemid, dmap.containeritemid&session-id=4409&revision-number=3
• /databases/32/containers/3897/items?type=music&meta=dmap.itemkind, dmap.itemid, dmap.containeritemid&session-id=4409&revision-number=3
• /databases/32/containers/3925/items?type=music&meta=dmap.itemkind, dmap.itemid, dmap.containeritemid&session-id=4409&revision-number=3
• /update?session-id=4409&revision-number=3&delta=3

the final stream request looks like

GET /databases/32/items/1553.mp3?session-id=4409 HTTP/1.1
Host: 10.0.1.7
Cache-Control: no-cache
Accept: */*
x-audiocast-udpport:49154
icy-metadata:1
User-Agent: iTunes/4.0 (Macintosh; N; PPC)
connection: close

Note the audiocast and icecast headers. The stream response is somewhat puzzling.

HTTP/1.1 200 OK
Date: Tue, 29 Apr 2003 04:02:59 GMT
DAAP-Server: iTunes/4.0 (Mac OS X)
Content-Type: application/x-dmap-tagged
Content-Length: 1696740
Accept-Ranges: bytes

It still claims to be x-dmap-tagged, but the content this time is clearly just the mp3 stream

More detailed dumps are available.

2003-04-28 22:36:00 | Comments (3) | TrackBack (0) | Computers::Macintosh