View source for Nintendo CDN Files

For information on the server itself, see [https://wiibrew.org/wiki/NUS NUS on WiiBrew].

== Files on the Nintendo CDN ==
On the Nintendo CDN, there are a few kinds of files for each game/title:
* Metadata (tmd)
* Ticket (cetk)
* Content files ('''00000000''' and up)

== Server File ID ==
Note that "we" refers to [[User:Hiccup|Hiccup]] and [[User:zedseven|zedseven]].<!-- Feel free to remove this bit - I'm not sure what the best format is for this information, hence the way it is at the moment. -->

In addition to the expected files (tmd, cetk, game content), there are a number of other files accessible by the same content ID system as is used to access game content.

If you try to access a non-existent file, the server gives you an error - for instance, with http://nus.cdn.t.shop.nintendowifi.net/ccs/download/0000000000000000/00000000 you get something akin to the following:

[[File:NUS-Screenshot-0000000000000000-00000000.png]]

(response header has 404 in status code, with Last-Modified field indicating that this page is generated on the fly)


The text in the square brackets appears to be some kind of server file id. Note that if you request a nonexistent cetk, it's server file id is reported as 4294967293 (0xFFFFFFFD).

[[File:NUS-Screenshot-0000000000000000-cetk.png]]

(with http://nus.cdn.t.shop.nintendowifi.net/ccs/download/0000000000000000/cetk)


Through this, we guessed that cetks do in fact have content IDs, and it turns out tmds also do, although if you request a tmd (either as "tmd" or "tmd.[version]", the server file ID is not reported by the error message (see [[#Special Content IDs]] for more info).

[[File:NUS-Screenshot-0000000000000000-tmd.png]]

(with http://nus.cdn.t.shop.nintendowifi.net/ccs/download/0000000000000000/tmd)


The function used for the server file ID is as follows:
<!-- LaTeX: f_{serverId}\left(t,c\right) = t \cdot \texttt{0x100000000} + c -->

[[File:Server-File-ID-Equation.png]]

Where '''t''' is the title ID, and '''c''' is the content ID.


== Special Content IDs ==
{| class="wikitable" 
|-
! 
! Wii
! DSi
! 3DS
! Wii U
|-
! FFFD0000
| ✓?
| ✓
| ✗?
| ✗?
|-
! FFFEFFFF
| ✓?
| ✓
| ✓?
| ✓?
|-
! FFFFFFFD
| ✓?
| ✓
| ✓?
| ✓?
|-
! FFFFFFFE
| ?
| ✓
| ?
| ✗?
|}

a ? mark in the table means not all known titles have been checked for this file, and maybe none have been checked

=== FFFD0000 ===
DSi Shop content starts at '''FFFD0000''' and increments up. This content is often icons and screenshots, (typically GIF or BMP interchangeably), with some ZIP file manuals for system titles mixed in as well.

=== FFFEFFFF ===
tmd content is stored at this content ID. The very first version is '''FFFEFFFF''', and subsequent versions decrement the value (second version is '''FFFEFFFE''', third is '''FFFEFFFD''', etc.).
Because tmd versions aren't sequential, this sequential versioning allows us to check if any versions have been deleted from the CDN.
No titles were found to have deleted versions.

=== FFFFFFFD ===
This is the content ID of cetk, if it exists for a given title.

=== FFFFFFFE ===
This is a file that exists for every existing title, however it is always 0 bytes in size.
We suspect it is used as a way of checking if a title exists on the CDN, since no other files have unchanging, consistent names (tmd kind of does, but we suspect it's auto-generated as the latest version - the file "tmd" probably doesn't exist on the server).