Hello, Uliweb¶

This tutorial will get you started with the Uliweb framework. In the following simple demo, we're going to generate a plain page which displays "Hello, Uliweb." step by step.

Getting Started¶

The first thing would be to read this article Installation,

a correct installation of Uliweb is a prerequisite.

Creating a new project¶

Uliweb provides a command line tool named uliweb, you can use it to execute several commands.

At the command line, change to or create a directory in which you want to create new Uliweb project, then execute:

uliweb makeproject project

If the command execution is successful, it'll output nothing and create a directory named hello_project. A clean workspace is created with relevant files for the project in this directory.

The project folder will be:

|-- app.yaml
|-- apps/
|   `-- settings.ini
|-- gae_handler.py
|-- runcgi.py
`-- wsgi_handler.wsgi

Creating the 'Hello' app¶

cd project
uliweb makeapp Hello

Go into project directory, create a new app following the command as shown. You can substitute the name of the app, Hello with another name of your choice.

After the command above is executed successfully, you can find the following files in apps/Hello directory:

|-- __init__.py
|-- conf.py
|-- info.ini
|-- static/
|   `-- readme.txt
|-- templates/
|   `-- readme.txt
`-- views.py

Starting the server¶

After the above steps, you can start up your web project as follows:

uliweb runserver

Following the instructions and information printout to the console, you can open a browser and enter the url http://localhost:8000. You would see a rendered page with the message "Hello, Uliweb" . Congratulations!

Modifying the "View"¶

When user requests an URL, Uliweb tries to map the URL to a view function. So in the case of our example, the request for http://localhost:8000 would map to a function thatmaps to the "/" location on our server. To see how this works, take a look in the Hello/view.py file. All your view functions should be declared in this file. Open it in your favourite editor, then you will see:

#coding=utf-8
from uliweb import expose

@expose('/')
def index():
    return '<h1>Hello, Uliweb</h1>'

The above code was generated automatically when you executing makeapp, and we even don't need write any code, the !

@expose('/') decorator is used for URL Mapping, which means map the url '/' to the view function below. So when visiting http://localhost:8000, function index() will be called. If a view function is not decorated by expose, it will not be mapped to any url and is treated as a local function.

This function will return a line of HTML code that will be displayed directly in browser.

Adding templates¶

If your view function returns a dict object, Uliweb will apply it to a template automatically. It means that different return value will cause a different action. The template is the same name as your view function with '.html' suffix. For example, the template of index() is index.html. Templates should be placed into the directory templates which will be automatically created when creating a new app. Now let's add a new function to test template process.

@expose('/template')
def template():
    return {}

Then create a new file template.html in apps/Hello/templates with contents like below:

<h1>Hello, Uliweb</h1>

Visit http://localhost:8000/template in the browser, you will see the same thing as the previous one.

Using template variables¶

In above two examples, all data are outputed directly, we're going to use template variables to change that. Add another view function with the following code:

@expose('/template1')
def template1():
    return {'content':'Uliweb'}

The function template1() returns a dict object with content which representing the content to be displayed. If you feel uncomfortable with the {}, try this alternative:

return dict(content='Uliweb')

or:

content = 'Uliweb'
return locals()

The first one uses dict() to construct a dict object while the second one uses the builtin function locals() directly - as long as you define the corresponding variables in current scope. Although locals() may return some irrelevant variables, it is not harmful.

Then create template1.html in apps/Hello/templates with contents like below:

<h1>Hello, {{=content}}</h1>

{{=content}} represents outputing value of content to template. Here you can use a variable or a function with return value between {{= and }}.

End¶

This tutorial only demonstrates some fundamental things like view and templates and lots of topics are not mentioned, such as:

• Organizing Apps
• Using Database
• Configurations
• etc.

You can find other documentation at http://uliwebproject.appspot.com.