httpy

Chad W. L. Whitacre

Zeta Design & Development
http://www.zetadev.com/software/httpy/
Email: chad@zetaweb.com

Abstract:

httpy is a Python module that smooths out WSGI's most glaring warts.

1. API Reference

The request side of WSGI--the "commons" of the environ mapping--is quite nice. It honors the tradition of CGI, and it's just a mapping. Simple.

The response-side API is a little stiffer, because WSGI has to support edge cases like serving large files, complex exception handling, and HTTP/1.1 features. This results in warts like start_response, and the requirement that apps return an iterable. The intention in PEP 333 is that these warts be smoothed over at other layers; this is such a layer.

httpy provides the following classes:

class Responder( app): Constructs a new Responder object. app is an extended WSGI application: it may alternately return a string, or return or raise a Response object.

class Response( [code] [, body] [, headers]): Constructs a new Response object. If given, code must be an integer; the default is 200 (see the HTTP spec for other values that will be meaningful to most HTTP clients). body must be a string. headers may be a dictionary or a list of 2-tuples. body is second rather than headers because one more often wants to specify a body without headers than vice versa.

1.1 `Responder` Objects

Instances of httpy.Responder are middleware that speak plain WSGI on the server side, but they also accept strings and Response objects from the application side. When a Responder receives a Response object, that becomes the WSGI endpoint. When a Responder receives a string, it creates a Response object with the string as the body, and the Content-Type: set to text/html. This implicit Response then becomes the endpoint.

1.2 `Response` Objects

Instances of httpy.Response are also plain WSGI applications, with the following data attributes. Note that values are only validated in the constructor, so it is currently possible to return/raise a malformed Response by setting instance attributes post-instantiation.

code: The HTTP code as an integer.

body: The message body as a string.

headers: The message headers as an instance of the standard library's email.Message.Message.

When called, Response instances call start_response with adaptations of code and headers, and return a one-item list containing body.

2. Example

Here is an example:

Python 2.5 (r25:52005, Sep 25 2006, 21:37:36)
[GCC 3.4.4 [FreeBSD] 20050518] on freebsd6
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> import httpy
>>> app = lambda env, start: "Greetings, program!"
>>> app = httpy.Responder(app)
>>>
>>> from wsgiref.simple_server import make_server
>>> server = make_server('', 8080, app)
>>> server.serve_forever() # now hit http://localhost:8080/
>>>
192.168.1.100 - - [09/Nov/2006 23:52:45] "GET / HTTP/1.1" 200 19

3. Copyright and License

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
Neither the name of Chad Whitacre nor the names of any other contributors or copyright holders may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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httpy

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