CH4 Intro

In the following sections, I will show you how everything operate:

section 1:What to do, how to do and something have to read;

section 2: What happen when running the program;

seciton 3:How to write flask function, tmplate and the jinja2;

section 4: How to write the view module(HTML);

section 5:How to debug and how my code hates me;

section 6: Different between writing code and novel.

Here is the relationship of view module(index.html) and the web.py(the flask function):

(1) cityname == input
(2) POST == the way how the flask function send the request(fetch the data)
(3) GET == the way how the flask function send the request to fetch the history and help
(4) save and query the "history" in the form of "list"
(5) data form API ,how to get and how to deal with it