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what to do?

Define your app’s requirements

Let’s think a little bit about what your Android app needs to do.

Nothing’s really
changed...you just
have to get the web
data onto the phone.

Frank: Well…first off, the view code no longer has to generate HTML,
so that makes things interesting.
Jill: In fact, you need the web server only to supply your data on
request, not all that generated HTML.
Joe: Ah ha! I’ve solved it. Just send the pickle with all the data from the
server to the Android phone. It can’t be all that hard, can it?

Jill: Sorry, guys, that’ll cause problems. The pickle format used by
Python 3 is incompatible with Python 2. You’ll certainly be able to send
the pickle to the phone, but the phone’s Python won’t be able to work
with the data in the pickle.

Frank: Darn…what are our options, then? Plain data?
Frank Joe
Jill Joe: Hey, good idea: just send the data as one big string and parse it on
the phone. Sounds like a workable solution, right?

Jill: No, that’s a potential disaster, because you never know in what
format that stringed data will arrive. You need an data interchange format,
something like XML or JSON.

Frank: Hmm…I’ve heard XML is a hound to work with…and it’s
probably overkill for this simple app. What’s the deal with JSON?
Joe: Yes, of course, I keep hearing about JSON. I think they use it in
lots of different places on the Web, especially with AJAX.
Frank: Oh, dear…pickle, XML, JSON, and now AJAX…I think my
brain might just explode here.
Jill: Never worry, you only need to know JSON. In fact, you don’t even
need to worry about understanding JSON at all; you just need to know
how to use it. And, guess what? JSON comes standard with Python
2 and with Python 3…and the format is compatible. So, we can use
JSON on the web server and on the phone.
Frank & Joe: Bonus! That’s the type of technology we like!

266 Chapter 8