Introduction

------------

WebStack is a package which provides a common API for Python Web

applications, regardless of the underlying server or framework environment.

It should be possible with WebStack to design and implement an application,

to choose a deployment environment, and then to be able to deploy the

application in a different environment later on without having to go back

and rewrite substantial parts of the application.

Quick Start

-----------

Try running the demo:

python tools/demo.py

An introductory guide to creating applications can be found in the docs

directory - see docs/index.html for the start page.

Contact, Copyright and Licence Information

------------------------------------------

The current Web page for WebStack at the time of release is:

http://www.boddie.org.uk/python/WebStack.html

Copyright and licence information can be found in the docs directory - see

docs/COPYING.txt, docs/LICENCE.txt and docs/LICENCE-PyServlet.txt for more

information.

Framework Support

-----------------

See the docs/supported-frameworks.html document for more information.

New in WebStack 1.2.6 (Changes since WebStack 1.2.5)

----------------------------------------------------

  * Improved support for Jython on Ubuntu Feisty (7.04), adding python.path

    and python.cachedir settings which respectively avoid issues with missing

    libraries (due to the separation of libraries in the Ubuntu package) and

    with failed imports (due to a read-only class cache directory).

  * Added more Jython-related documentation as suggested by Kevin Glynn.

  * Added missing request headers for CGI/WSGI environment variables.

New in WebStack 1.2.5 (Changes since WebStack 1.2.4)

----------------------------------------------------

  * Fixed mod_python status codes using a solution proposed by John Krukoff.

  * Fixed a Twisted deprecation warning when accessing port numbers, thanks to

    John Krukoff.

  * Added Ubuntu Feisty (7.04) package support.

  * Tidied up the documentation HTML.

New in WebStack 1.2.4 (Changes since WebStack 1.2.3)

----------------------------------------------------

  * Made a SessionDirectoryRepository which uses directories for data produced

    by the shelve module, rather than attempting to manipulate files produced

    by the shelve module, since the details of such files may differ between

    environments: a situation noticed by John Krukoff in an environment

    without the bsddb module installed.

New in WebStack 1.2.3 (Changes since WebStack 1.2.2)

----------------------------------------------------

  * Fixed inadvertent OpenSSL dependency, noticed by John Krukoff.

New in WebStack 1.2.2 (Changes since WebStack 1.2.1)

----------------------------------------------------

  * Added an EncodingSelector class for the setting of default encodings on

    transactions.

  * Added some documentation about path processing strategies.

  * Added a secure variant of the BaseHTTPServer provided in the adapter for

    BaseHTTPRequestHandler.

New in WebStack 1.2.1 (Changes since WebStack 1.2)

--------------------------------------------------

  * Fixed mod_python get_content_type method.

  * Fixed LoginResource form field processing; changed the field type to

    password.

  * Exposed LoginResource and LoginRedirectResource page contents as

    attributes.

  * Added documentation about extending LoginRedirectResource and using

    PathSelector to remember an application's root path.

  * Changed handle_errors to 1 throughout the examples.

New in WebStack 1.2 (Changes since WebStack 1.1.2)

--------------------------------------------------

  * Added support for Django.

  * Fixed documentation about the representation of file upload fields.

  * Changed mod_python, Java Servlet and Webware (> 0.8.1) deployment to use a

    deploy function instead of more complicated configuration mechanisms.

  * Improved mod_python deployment documentation and tools so that cleaner

    application paths/URLs can now be used.

  * Moved user and path_info default definitions into WebStack.Generic as

    class attributes.

  * Fixed encoding usage issues with path fields when using get_fields in a

    Zope environment.

  * Added a FileResource class to WebStack.Resources.Static.

  * Made DirectoryRepository convert filenames to Unicode in all cases.

  * Renamed the Apache and Java Servlet tools, making them scripts which are

    installed by setup.py.

  * Fixed CGI content charsets and languages support.

  * Fixed CGI cookie output.

  * Added URL overriding in the LoginRedirectResource.

  * Exposed a get_target function from WebStack.Resources.Login in order to

    better support alternative login resources.

  * Added improved error reporting for BaseHTTPRequestHandler, CGI, Django and

    WSGI.

  * Added a traverse_path method to the Transaction class.

  * Made a path_encoding alias for urlencoding in the initialisation of

    WebStack.Resources.ResourceMap objects.

  * Added a Selectors module to WebStack.Resources in order to support common

    resource selection patterns.

New in WebStack 1.1.2 (Changes since WebStack 1.1.1)

----------------------------------------------------

  * Fixed missing import in WebStack.Repositories.Directory.

New in WebStack 1.1.1 (Changes since WebStack 1.1)

--------------------------------------------------

  * Fixed update_path to handle the root path properly.

New in WebStack 1.1 (Changes since WebStack 1.0)

------------------------------------------------

  * Added a Repositories package to provide session-like support for

    different kinds of storage.

  * Added an explicit filesystem encoding to the Calendar example and adopted

    the DirectoryRepository from the Repositories package.

  * Added get_path_without_info, update_path and redirect methods to the

    Transaction class.

  * Added get_attributes (attribute support) to the Transaction class.

  * Added a values method to Helpers.Session.Wrapper.

  * Fixed get_processed_virtual_path_info (to match from right to left).

  * Improved/fixed exception handling in the adapters so that transactions are

    committed as the final act of an adapter experiencing an unhandled

    exception. This should result in session stores being closed properly.

  * Changed the Helpers.Session.SessionStore to use DirectoryRepository.

  * Made the "not found" behaviour of DirectoryResource more configurable.

  * Added documentation for MapResource and DirectoryResource.

  * Fixed the distribution names in the Ubuntu changelog.

New in WebStack 1.0 (Changes since WebStack 0.10)

-------------------------------------------------

  * Changed the behaviour of get_path, get_path_without_query, get_path_info,

    get_virtual_path_info, get_processed_virtual_path_info and

    get_fields_from_path to return Unicode data decoded using the optional

    encoding parameter or a common default encoding.

  * Fixed file upload values so that FileContent objects are returned for such

    fields in get_fields_from_body and get_fields.

    (Warning! Except for Twisted!)

  * Fixed the JavaServlet support so that streams and file content are

    obtained as "almost" plain strings.

  * Updated/fixed LoginResource and LoginRedirectResource to use the updated

    path API and to handle special characters properly.

  * Added convenience methods to Transaction for the decoding and encoding of

    path values (to and from Unicode objects) - see the decode_path and

    encode_path methods.

  * Added the notion of processed virtual path info - the part of the original

    path info not represented in the current virtual path info.

  * Added "pass through" behaviour to ResourceMap.MapResource (prompted by a

    patch from Scott Robinson).

  * Fixed ResourceMap.MapResource to handle non-existent resources properly

    (where the virtual path info is only one component in length).

  * Added Debian package support.

  * Added automatic session directory creation for the WebStack sessions

    implementation.

  * Added support for the repeated retrieval of sessions from the same

    WebStack session store, avoiding deadlocks.

  * Fixed the calendar example, making it perform a proper function.

  * Made the BaseHTTPRequestHandler and Twisted SimpleWithLogin applications

    include the Login application, since Konqueror (at least) does not share

    cookies across different port numbers on the same host.

  * Added the SimpleWithLogin and Login applications to the demonstration.

  * Improved the documentation, adding information on request headers, and

    describing file upload and session support limitations.

  * Improved the AOLserver-related notes for CGI and Webware, adding a patch

    for Webware in order to work around AOLserver issues.

New in WebStack 0.10 (Changes since WebStack 0.9)

-------------------------------------------------

  * Changes to make the tools/demo.py script work on Windows (and other)

    platforms (suggested by Jim Madsen).

  * Fixed end of header newlines for CGI (suggested by Matt Harrison).

  * Minor documentation fixes and improvements, adding information on

    AOLserver in the CGI and Webware notes.

  * Changed the mod_python server name method to use the server object rather

    than the connection object.

  * Added a parameter to the ResourceMap.MapResource class to permit automatic

    redirects into resource hierarchies when no trailing "/" was given in the

    URL; changed the updated virtual path info so that empty values may be set

    (the guarantee that "/" will always appear no longer applies).

  * Fixed virtual path info retrieval when the value is an empty string.

New in WebStack 0.9 (Changes since WebStack 0.8)

------------------------------------------------

  * Standardised error handling in the adapters so that tracebacks can be

    suppressed and an internal server error condition raised.

  * Added overriding of path info in transactions.

  * Added a ResourceMap resource for dispatching to different resources

    according to path components.

  * Standardised deployment for some frameworks (see docs/deploying.html).

  * Introductory documentation in XHTML format.

  * Added server name and port methods to the transaction.

  * Added a simple demonstration application, incorporating many of the

    examples and launched under a single script.

  * Fixed mod_python native sessions.

  * Fixed Zope request stream access.

  * WebStack is now licensed under the LGPL - see docs/COPYING.txt for

    details.

New in WebStack 0.8 (Changes since WebStack 0.7)

------------------------------------------------

  * Added a standard exception, EndOfResponse, which can be used to

    immediately stop the processing/production of a response; this is useful

    when resources need to issue a redirect without unnecessary content being

    generated, for example.

  * Fixed path information for Zope.

  * Added WSGI support.

  * Verified Twisted 1.3.0 support with Python 2.3.3.

New in WebStack 0.7 (Changes since WebStack 0.6)

------------------------------------------------

  * Fixed path information semantics.

  * Fixed file upload semantics.

  * Fixed content type handling for Unicode output and for interpreting

    request body fields/parameters (although some improvement remains).

  * Added a method to discover the chosen response stream encoding.

  * Fixed field/parameter retrieval so that path and body fields are distinct,

    regardless of the framework employed.

  * Added a method to get a combination of path and body fields (suggested by

    Jacob Smullyan).

  * Introduced Zope 2 support.

  * Improved Jython/Java Servlet API support (although a special PyServlet

    class must now be used, and certain libraries must be deployed with

    applications).

  * Introduced authentication/authorisation support for Jython/Java Servlet

    API.

  * Session support has been added (except for Webware 0.8.1).

  * Alternative cookie support for mod_python has been added.

  * Cookie support now supports encoded Unicode sequences for names and

    values.

New in WebStack 0.6 (Changes since WebStack 0.5)

------------------------------------------------

  * Introduced Jython/Java Servlet API support.

  * Minor fixes to example applications and to BaseHTTPRequestHandler.

New in WebStack 0.5 (Changes since WebStack 0.4)

------------------------------------------------

  * Changed request body fields/parameters so that they are now represented

    using Unicode objects rather than plain strings.

  * Introduced better support for Unicode in response streams.

New in WebStack 0.4 (Changes since WebStack 0.3)

------------------------------------------------

  * Added application definition of user identity, permitting alternative

    authentication mechanisms.

  * Improved BaseHTTPRequestHandler and mod_python reliability around fields

    from request bodies.

  * Provided stream and environment parameterisation in the CGI adapter.

  * Added LoginRedirect and Login examples.

  * Added get_path_without_query and fixed get_path behaviour.

New in WebStack 0.3 (Changes since WebStack 0.2)

------------------------------------------------

  * Added better header support for Webware (suggested by Ian Bicking).

  * Introduced CGI and Java Servlet support (the latter is currently

    broken/unfinished).

  * Introduced support for cookies.

Future Work

-----------

(Essential)

Twisted 1.3.0 does not provide file upload metadata, and Twisted Web 0.5.0

also seems to be missing this functionality. It isn't obvious whether Twisted

Web2 will just copy its predecessors and provide a similarly limited API.

Perhaps the Twisted support needs to resemble the CGI support much more when

handling fields.

JythonServlet libraries need to be configured using sys.add_package when

these do not feature in the compiled-in list. Adding such configuration to

the handler may be most appropriate (since the web.xml file can be too

arcane), but this needs testing.

The algorithm employed in the WebStack.Helpers.Auth.get_token function

should be reviewed and improved for better security.

(Important)

Field access needs testing, especially for anything using the

cgi.FieldStorage class, and the way file uploads are exposed should be

reviewed (currently the meta-data is not exposed). The acquisition of fields

from specific sources should be tested with different request methods - some

frameworks provide path fields in the body fields dictionary, others (eg.

Zope) change the fields exposed depending on request method.

Interpretation of path field encodings needs to be verified. Currently,

stray path fields are handled (eg. in WebStack.Helpers.Request) as being

ISO-8859-1, but it might be the case that some such fields might be

submitted as UTF-8. The decode_path method on Transaction does do much of the

work that is likely to be required, however. Still, a good policy for decoding

path fields, reducing the number of times one might specify the encoding in

various method calls, may be important.

An interesting test of encodings is to introduce things like the following to

the path info and query string sections of the URL: %25F0?%E6=%F8&%25F0=%F8

This should produce the following decoded result: %F0?æ=ø&%F0=ø

(The above needs to be read in ISO-8859-1 or ISO-8859-15.)

Cookie objects need defining strictly, especially since the standard library

Cookie object behaves differently to mod_python (and possibly Webware)

Cookie objects. Moreover, the set_cookie_value method needs to provide

access to the usual cookie parameters as supported by the frameworks. The

standard library Cookie module has issues with Unicode cookie names (and

possibly values) - this is worked around, but it would be best to resolve

this comprehensively.

UTF-16 (and possibly other encodings) causes problems with HTML form data

sent in POST requests using the application/x-www-form-urlencoded content

type.  This should be reviewed at a later date when proper standardisation

has taken place.

Session support, especially through WebStack.Helpers.Session, should be

reviewed and be made compatible with non-cookie mechanisms.

Locking in the session support and in DirectoryRepository should be improved.

HeaderValue objects should be employed more extensively. Thus, the header

access methods may need to change their behaviour slightly. The get_headers

method should potentially return a list for each item in the dictionary.

WSGI support could demand that a special "end of headers" method be

introduced into WebStack, thus making response output more efficient (and

probably also for other frameworks, too).

Investigate proper support for HEAD, OPTIONS and other request methods.

Consider packages for different operating systems (other than Debian).

Investigate cStringIO usage.

The location of deployed applications in the filesystem should be exposed to

those applications. (This is actually available in the __file__ module

variable.) A resource could be provided to record the "root" path and added to

a resource hierarchy or site map. Note that PathSelector records the "root"

path, although it is not automatically deployed.

(Completed/rejected)

Path information should be consistent across all frameworks, and the "path

info" value should be meaningful. (This should now be correct.)

Investigate the nicer functions in the cgi module, discarding the "magic"

stuff like FieldStorage. (These nicer functions are used by projects like

Twisted - as of 1.3.0 at least - and do not give the necessary information we

require.)

Release Procedures

------------------

Update the WebStack/__init__.py __version__ attribute.

Change the version number and package filename/directory in the documentation.

Change code examples in the documentation if appropriate.

Update the release notes (see above).

Check the setup.py file and ensure that all package directories are mentioned.

Check the release information in the PKG-INFO file and in the package

changelog (and other files).

Tag, export.

Generate the PyServlet classes.

Generate the API documentation.

Remove generated .pyc files: rm `find . -name "*.pyc"`

Archive, upload.

Upload the introductory documentation.

Update PyPI, PythonInfo Wiki, Vaults of Parnassus entries.

Generating the API Documentation

--------------------------------

In order to prepare the API documentation, it is necessary to generate some

Web pages from the Python source code. For this, the epydoc application must

be available on your system. Then, inside the distribution directory, run the

apidocs.sh tool script as follows:

./tools/apidocs.sh

Some warnings may be generated by the script, but the result should be a new

apidocs directory within the distribution directory.

Making Packages

---------------

To make Debian-based packages:

  1. Create new package directories under packages if necessary.

  2. Make a symbolic link in the distribution's root directory to keep the

     Debian tools happy. For example:

     ln -s packages/ubuntu-hoary/python2.4-webstack/debian/

     ln -s packages/ubuntu-feisty/python-webstack/debian/

  3. Run the package builder:

     dpkg-buildpackage -rfakeroot

  4. Locate and tidy up the packages in the parent directory of the

     distribution's root directory.