On Monday, March 31, 2003, at 11:42 PM, Stipe Tolj wrote:
I'm looking at WAP-209-MMSEncapsulation-20020105-a.pdf and my hex dump. As an example, I'm looking for the 'Message-Type' field (0x0c according to section 7.3) which should be equal to 'm-send-req' (0x80, according to section 7.2.14.). I would expect to find a sequence of 0x0c 0x80 but it's not there.
NOP!! that's the first gap all of us fall in. The Tabe 8 (sectin 7.3) tells the offset values to 0x80 as defined in WAP-WSP tables.
Hmm. How on earth would I have known that? :) I figured with about 3 documents in front of me I'd have enough but nooooo! I also need the WSP spec (WAP-203-WSP-20000504-a.pdf in WAP 1.2.1 which is WAP-230-WSP-20010705-a.pdf in WAP 2.0)... Luckily that one has some examples on decoding.
Those specs are really hard to work with!
What am I missing? Is there (yet) another encoding going on that I'm forgetting about?
Here's the start of my hex dump:
[MMS]0x8c 140 ? [MMS]0x80 128 ?
yep here you go: 0x8c is 0x80 (dec 128) as a base + 0x0c for the 'Message-Type' field. So these two tokens represent the Header
Message-Type: m-send-req
Right, thanks, at least I have a little head start now.
and so on. These are the "easy" things. It gets harder when you don't have direct two pairs that represent the field name and field value. But as I said, you can do this allmost all with WSP code of Kannel.
I'm not sure what's better: trying to understand it with the specs or by reading the WSP code in Kannel :)
Thanks a bunch, gonna do some more decoding today
BTW, can anyone recommend a good resource on this (besides the specs themselves)? A book maybe or a web page? Better examples sure would help out here!
Bas.
