RE: FN-FORUM wap emulators anyone? - LONGish

date posted 27th June 2002 12:08

Hi,

I started working with WAP before the formation of the WAP Forum with a
company called Spyglass (some of you may recall them, have a look at help
about in IE if you dont). The first device on the market was the Nokia 7110
which was extremely bug ridden and had lots of quirks in its implementation.
Designing applications to fit into under 1300 bytes of encoded data was
difficult. Compounded with the fact that there is a gateway between your
code and the final device that could also introduce its own problems
development was interesting to say the least. Having said that I was
luckily responsible for a site that was intended as a demonstration site but
in the end was rated top WAP application by one French site. If I can help
anyone out with WAP I would be more than happy to do so.

As a brief introduction:

Wap Forum (Wireless Application Protocol) is the equivelant of the W3C in
some ways and WAP itself is a collection of protocols optimised for wireless
networks in a parallel way to normal web sites. Some key protocols are

wml - html the markup language
wbml - Byte encoded version of the wml, sometimes reffered to as compiled
wtp - http the server communications
wsp - javascript

In a very simplistic overview WAP devices or clients normally talk WTP to a
wap gateway. The gateway will talk http to a normal web server and request
the files from the server. The output should be in WML format and the
gateway will convert the WML into a byte encoded format and send it to the
phone.

It is possible for the originating site ie web server to send out content
already encoded as WBXML and the gateway should transfer this transparently
to the client.

If you look at Nokia emulators you will see that they have two versions of
the 7110 to choose from. Even if you get your application to work in the
emulator though there is no promise it will work in the real phone.

Nowadays there are hundreds of different phones on the market with a wide
variety of screen sizes, user input mechanisms and range from small phones
to larger PDA. The top end is probably Opera Browser which implements WML
support natively.

The long shot of it is that if you are designing anything for a WAP device
the more traditional problems associated with Netscape/IE compatibility fall
away in comparison as they at least degrade without complaining too much.
If your WML decks are not validatable your device will not show them and may
even hang requiring battery removal in some cases. You need to make sure
your site works in all the major emulators first of all and on at least a
Nokia, Ericsson and Open Wave based device.

Now to the original question posed on how to get an application to run in an
emulator.

Certain HTTP headers are required to be set on the server to set the mime
types for the output content to either WML or WBML. If you use PHP or ASP
then this should not be a problem as they can be added in the code. If you
use a static site then the server needs to be configured to automaticaly
send the correct headers to match the file extension. Most current versions
of Apache already have these set I believe.

From my experience few emulators register themselves as the default renderer
for WML pages. So it is almost impossible to get a link on a web page to
cause a PC to automaticaly load an emulator and go directly to the
particular page on the link. [My experience with current emulators is about
4 months out of date so things may have changed]

So you are left with a situation of using Java emulators if you require some
form of demonstration capability. However to go back to the begining of
this little epic, it is most important that the site operates on real phones
correctly rather than being a nice little demo, after all if all that is
required is to run this in a web browser why not use Flash or HTML ?

Hope this has been of use to some of you,

If my over simplification of things confuses people or upsets them please
accept my appologies in advance.

Regards,

Carl Taylor
Tel: 01489 557 545
Fax: 01489 576 502
http://www.adepteo.com