[Zope] WAP/WML for Cell Phone Wireless Web?

[Duncan Booth]

> Has anyone looked at using Zope to serve WML (wireless markup
> language) pages that can be read by cell-phones.  I'm here in
> Washington DC, and it seems as if Sprint PCS will have this
> service soon.  It sounds pretty good.
See http://www.rcp.co.uk/distributed/wapdemo for a demonstration 
WAP application written using Zope (HTML pages with screenshots, 
and also a link to the actual demo for those with WAP browsers).
You need a Nokia toolkit to run the demo, there are issues using a 
real 7110, or a non-Nokia browser.

> So all a zope site would have to do is add a new mime type
> (not sure what it is), and serve up the wml rather than html.
Setting the mime type is the easy bit. Actually my 
standard_wap_header checks the browser and sets the mime type 
to text/plain if it is begins with Mozilla, and WAP otherwise. This is 
useful for debugging.

standard_wap_header:
<?xml version="1.0"?> 
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" 
"http://www.wapforum.org/DTD/wml_1.1.xml">
<!-- content-type set in footer -->
<wml>

standard_wap_footer:
</wml>
<dtml-if "HTTP_USER_AGENT[:7]!='Mozilla'">
<dtml-call "RESPONSE.setHeader('Content-Type', 
'text/vnd.wap.wml')">
<dtml-else>
<dtml-call "RESPONSE.setHeader('Content-Type', 'text/plain')">
</dtml-if>

Harder bits include:
POST doesn't work with some browsers (I am told the authors on at 
least one browser claim that the standard makes it perfectly legal to 
use a page from cache instead of rerequesting a page even if it was 
originally returned as a result of a POST with different field values.)
I also hear that the 7110 limits URLs to 127 characters, so that kind 
of messes up storing session information in the request string, 
although that is what my demo currently does).
The phone variables may be cleared on a least recently used basis 
at any time, so you cannot reliably store session information there 
either. Cookies are not supported by any of the existing gateways, 
(apparently this is because privacy issues preclude the identity of 
the phone being made available to the gateway).

Decks are limited to 1400 bytes after compilation. Compilation 
normally makes pages smaller, but can make them larger. (A python 
WML compiler would be really useful here.) A lot of my zope code 
was to do with splitting long lists up into smaller lists spread over 
multiple decks.

Strange inconsistencies between browser make it almost impossible 
to write one WAP application that runs on more than one browser. 
for example, the top page of my demo includes two links on the 
options menu which on the Nokia emulator are listed with 
appropriate captions. On the Nokia 7110 phone these links both 
display with the caption 'Unknown'.

-- 
Duncan Booth                                             duncan@dales.rmplc.co.uk
int month(char *p){return(124864/((p[0]+p[1]-p[2]&0x1f)+1)%12)["\5\x8\3"
"\6\7\xb\1\x9\xa\2\0\4"];} // Who said my code was obscure?
http://dales.rmplc.co.uk/Duncan