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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 processes the request to generate a response in one way or another.

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: simply 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 (as provided by the webob package)
response
The Response object (as provided by the webob package)
separated()
Helper function that converts a list of strings into a single string with added separators
time
Python time class from the datetime module
timedelta
Python timedelta class from the datetime module
truncate()
Helper function that truncates a string to a specified limit of characters, taking word boundaries into account
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.auth:login
Handle a form-based authentication request
diva.auth:logout
Clears a previously set authentication cookie
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 with the default context data

API Documentation

Error: Macro PythonDoc(trunk, diva.http) failed
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Error: Macro PythonDoc(trunk, diva.templating) failed
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Last modified 8 years ago Last modified on Sep 17, 2008, 10:07:26 PM