Request Handlers

A request handler is a neutral name for what some other frameworks call “controllers” or “views”. It is simply a Python function that accepts the request and response objects as parameters, and returns a response.

from diva.templating import output, render

@output('index.html')
def index(request, response):
    return render(message='Hello, world!')

This defines a function called index that will respond to requests by rendering the template index.html.

URL Parts as Parameters

Any dynamic parts of the URLs defined in the UrlRouting are passed to the request handler as additional parameters. For example:

from datetime import datetime
from diva import app
from diva.templating import output, render

@output('index.html')
def monthly(request, response, year, month):
    return render(month=datetime(year, month, 1))

app.routing.add('/archives/{year:\d+}/{month:\d+}/', monthly)

Note that in this particular case, the values for year and month are automatically converted to numbers, due to the use of the \d+ pattern in the route path.

Rendering Genshi Templates

The diva.templating module provides convenience functions for rendering Genshi templates.

First, there's the @output decorator, which you use to specify the name of the template file, the serialization method, the response MIME type and encoding, and other serialization options such as the DOCTYPE to use and so on.

from diva.templating import output, render

@output('index.html', method='html', doctype='html-strict')
def index(request, response):
    return render(message='Hello, world!')

Note that all of the arguments to @output are optional. For example, you can omit the template file name for a response that doesn't involve template rendering, and just use the mimetype and encoding options:

@caching(max_age=timedelta(days=7))
@output(mimetype='text/css', encoding='utf-8')
def style(request, response, font_size=1):
    return 'html { font-size: %sem; }' % font_size

If you do want to render a template, use the render() function to return a Genshi stream from the request handler. You pass any template data into the render() function as keyword arguments, and it will generate an output stream from the template based on the template data. The render() function also lets you override the template filename specified using the @output decorator: simple pass the template name as the first (and only) positional argument into render().

Default Template Data

Diva makes a number of objects available for use in Genshi templates by default:

app

The Application object

abs_url()

Function for converting relative paths to absolute URLs

attrgetter

Function from the Python operator module

classes

Helper function to generate CSS class names for use in HTML templates

date

Python date class from the datetime module

datetime

Python datetime class from the datetime module

_() / gettext()

Function for translating a message

HTML()

Function to parse a string as HTML and return a markup stream

group

Helper function for splitting flat lists up into groups of items (like columns)

groupby

Function from the Python itertools module

itemgetter

Function from the Python operator module

ngettext()

Function for translating a message including plural forms

path_to()

Function for generating URLs based on the routing configuration

request

The Request object

response

The Response object

separated

Helper function that adds separator strings to a list of strings

time

Python time class from the datetime module

timedelta

Python timedelta class from the datetime module

XML()

Function to parse a string as XML and return a markup stream

Builtin Request Handlers

Diva comes with a couple of generic request handlers that can be used as-is with some parameterization in UrlRouting.

diva.routing:delegate

Delegate request processing to a different WSGI application.

diva.routing:redirect

Send an HTTP redirect to a different URL

diva.static:directory

Serve static files from a specific directory

diva.static:file

Serve a specific static file

diva.templating:view

Render a given template

API Documentation

Error: Macro PythonDoc(trunk, diva.http) failed

Unsupported version control system "svn": No module named svn

Error: Macro PythonDoc(trunk, diva.templating) failed

Unsupported version control system "svn": No module named svn