Day 23 - Th, April 18, 2013¶
Schedule:
- Minute cards.
- AJAX and JSON-RPC
- More database: joins, transactions, multithreading, synch, etc.
Questions/TODO¶
(This is an example of using the jQuery JavaScript library with AJAX and JSON-RPC)
Grab the latest version of https://github.com/ctb/cse491-webz; for example, on the CSE cluster, you could do:
mkdir day23
cd day23
python2.7 -m virtualenv env
source env/bin/activate.csh
pip install simplejson
to get the environment running, and then
git clone https://github.com/ctb/cse491-webz.git
cd cse491-webz
python app.py
Now, go to the URL of the Web server, and take a look at the ‘/content’ URL, which is loading from ‘somefile.html’. (You can look at the source of ‘somefile.html’ on github, if you want.)
On the ‘/content’ page, you’ll see three input box regions
The value in the first is set dynamically by JavaScript using the jQuery library.
The value in the second is output in an alert box upon change.
The two values in the third are summed and displayed on the page.
TODO:
- At your table, talk through the code for the first and second input boxes. What’s going on? (One thing you can do to find out is edit the HTML to remove the first <script>, which loads jQuery; this will disable all the JavaScript.)
- For the third input box (“retrieve from server”), write down a flowchart on your whiteboard that details, in order, what happens in terms of network traffic and function calls in Python (on the server side) and JavaScript (on the client side). Your flowchart should include
- For the last text box (“retrieve from server”), why does an alert box pop up after you enter the first value?
Minute Cards¶
In the last 5 minutes of class, please fill out this minute card survey.