WebStack

README.txt

620:c091bb3733be
2007-01-20 paulb [project @ 2007-01-20 23:15:29 by paulb] Added the EncodingSelector class.
     1 Introduction
     2 ------------
     3 
     4 WebStack is a package which provides a common API for Python Web
     5 applications, regardless of the underlying server or framework environment.
     6 It should be possible with WebStack to design and implement an application,
     7 to choose a deployment environment, and then to be able to deploy the
     8 application in a different environment later on without having to go back
     9 and rewrite substantial parts of the application.
    10 
    11 Quick Start
    12 -----------
    13 
    14 Try running the demo:
    15 
    16 python tools/demo.py
    17 
    18 An introductory guide to creating applications can be found in the docs
    19 directory - see docs/index.html for the start page.
    20 
    21 Contact, Copyright and Licence Information
    22 ------------------------------------------
    23 
    24 The current Web page for WebStack at the time of release is:
    25 
    26 http://www.boddie.org.uk/python/WebStack.html
    27 
    28 Copyright and licence information can be found in the docs directory - see
    29 docs/COPYING.txt, docs/LICENCE.txt and docs/LICENCE-PyServlet.txt for more
    30 information.
    31 
    32 Framework Support
    33 -----------------
    34 
    35 See the docs/supported-frameworks.html document for more information.
    36 
    37 New in WebStack 1.2.2 (Changes since WebStack 1.2.1)
    38 ----------------------------------------------------
    39 
    40   * Added an EncodingSelector class for the setting of default encodings on
    41     transactions.
    42   * Added some documentation about path processing strategies.
    43 
    44 New in WebStack 1.2.1 (Changes since WebStack 1.2)
    45 --------------------------------------------------
    46 
    47   * Fixed mod_python get_content_type method.
    48   * Fixed LoginResource form field processing; changed the field type to
    49     password.
    50   * Exposed LoginResource and LoginRedirectResource page contents as
    51     attributes.
    52   * Added documentation about extending LoginRedirectResource and using
    53     PathSelector to remember an application's root path.
    54   * Changed handle_errors to 1 throughout the examples.
    55 
    56 New in WebStack 1.2 (Changes since WebStack 1.1.2)
    57 --------------------------------------------------
    58 
    59   * Added support for Django.
    60   * Fixed documentation about the representation of file upload fields.
    61   * Changed mod_python, Java Servlet and Webware (> 0.8.1) deployment to use a
    62     deploy function instead of more complicated configuration mechanisms.
    63   * Improved mod_python deployment documentation and tools so that cleaner
    64     application paths/URLs can now be used.
    65   * Moved user and path_info default definitions into WebStack.Generic as
    66     class attributes.
    67   * Fixed encoding usage issues with path fields when using get_fields in a
    68     Zope environment.
    69   * Added a FileResource class to WebStack.Resources.Static.
    70   * Made DirectoryRepository convert filenames to Unicode in all cases.
    71   * Renamed the Apache and Java Servlet tools, making them scripts which are
    72     installed by setup.py.
    73   * Fixed CGI content charsets and languages support.
    74   * Fixed CGI cookie output.
    75   * Added URL overriding in the LoginRedirectResource.
    76   * Exposed a get_target function from WebStack.Resources.Login in order to
    77     better support alternative login resources.
    78   * Added improved error reporting for BaseHTTPRequestHandler, CGI, Django and
    79     WSGI.
    80   * Added a traverse_path method to the Transaction class.
    81   * Made a path_encoding alias for urlencoding in the initialisation of
    82     WebStack.Resources.ResourceMap objects.
    83   * Added a Selectors module to WebStack.Resources in order to support common
    84     resource selection patterns.
    85 
    86 New in WebStack 1.1.2 (Changes since WebStack 1.1.1)
    87 ----------------------------------------------------
    88 
    89   * Fixed missing import in WebStack.Repositories.Directory.
    90 
    91 New in WebStack 1.1.1 (Changes since WebStack 1.1)
    92 --------------------------------------------------
    93 
    94   * Fixed update_path to handle the root path properly.
    95 
    96 New in WebStack 1.1 (Changes since WebStack 1.0)
    97 ------------------------------------------------
    98 
    99   * Added a Repositories package to provide session-like support for
   100     different kinds of storage.
   101   * Added an explicit filesystem encoding to the Calendar example and adopted
   102     the DirectoryRepository from the Repositories package.
   103   * Added get_path_without_info, update_path and redirect methods to the
   104     Transaction class.
   105   * Added get_attributes (attribute support) to the Transaction class.
   106   * Added a values method to Helpers.Session.Wrapper.
   107   * Fixed get_processed_virtual_path_info (to match from right to left).
   108   * Improved/fixed exception handling in the adapters so that transactions are
   109     committed as the final act of an adapter experiencing an unhandled
   110     exception. This should result in session stores being closed properly.
   111   * Changed the Helpers.Session.SessionStore to use DirectoryRepository.
   112   * Made the "not found" behaviour of DirectoryResource more configurable.
   113   * Added documentation for MapResource and DirectoryResource.
   114   * Fixed the distribution names in the Ubuntu changelog.
   115 
   116 New in WebStack 1.0 (Changes since WebStack 0.10)
   117 -------------------------------------------------
   118 
   119   * Changed the behaviour of get_path, get_path_without_query, get_path_info,
   120     get_virtual_path_info, get_processed_virtual_path_info and
   121     get_fields_from_path to return Unicode data decoded using the optional
   122     encoding parameter or a common default encoding.
   123   * Fixed file upload values so that FileContent objects are returned for such
   124     fields in get_fields_from_body and get_fields.
   125     (Warning! Except for Twisted!)
   126   * Fixed the JavaServlet support so that streams and file content are
   127     obtained as "almost" plain strings.
   128   * Updated/fixed LoginResource and LoginRedirectResource to use the updated
   129     path API and to handle special characters properly.
   130   * Added convenience methods to Transaction for the decoding and encoding of
   131     path values (to and from Unicode objects) - see the decode_path and
   132     encode_path methods.
   133   * Added the notion of processed virtual path info - the part of the original
   134     path info not represented in the current virtual path info.
   135   * Added "pass through" behaviour to ResourceMap.MapResource (prompted by a
   136     patch from Scott Robinson).
   137   * Fixed ResourceMap.MapResource to handle non-existent resources properly
   138     (where the virtual path info is only one component in length).
   139   * Added Debian package support.
   140   * Added automatic session directory creation for the WebStack sessions
   141     implementation.
   142   * Added support for the repeated retrieval of sessions from the same
   143     WebStack session store, avoiding deadlocks.
   144   * Fixed the calendar example, making it perform a proper function.
   145   * Made the BaseHTTPRequestHandler and Twisted SimpleWithLogin applications
   146     include the Login application, since Konqueror (at least) does not share
   147     cookies across different port numbers on the same host.
   148   * Added the SimpleWithLogin and Login applications to the demonstration.
   149   * Improved the documentation, adding information on request headers, and
   150     describing file upload and session support limitations.
   151   * Improved the AOLserver-related notes for CGI and Webware, adding a patch
   152     for Webware in order to work around AOLserver issues.
   153 
   154 New in WebStack 0.10 (Changes since WebStack 0.9)
   155 -------------------------------------------------
   156 
   157   * Changes to make the tools/demo.py script work on Windows (and other)
   158     platforms (suggested by Jim Madsen).
   159   * Fixed end of header newlines for CGI (suggested by Matt Harrison).
   160   * Minor documentation fixes and improvements, adding information on
   161     AOLserver in the CGI and Webware notes.
   162   * Changed the mod_python server name method to use the server object rather
   163     than the connection object.
   164   * Added a parameter to the ResourceMap.MapResource class to permit automatic
   165     redirects into resource hierarchies when no trailing "/" was given in the
   166     URL; changed the updated virtual path info so that empty values may be set
   167     (the guarantee that "/" will always appear no longer applies).
   168   * Fixed virtual path info retrieval when the value is an empty string.
   169 
   170 New in WebStack 0.9 (Changes since WebStack 0.8)
   171 ------------------------------------------------
   172 
   173   * Standardised error handling in the adapters so that tracebacks can be
   174     suppressed and an internal server error condition raised.
   175   * Added overriding of path info in transactions.
   176   * Added a ResourceMap resource for dispatching to different resources
   177     according to path components.
   178   * Standardised deployment for some frameworks (see docs/deploying.html).
   179   * Introductory documentation in XHTML format.
   180   * Added server name and port methods to the transaction.
   181   * Added a simple demonstration application, incorporating many of the
   182     examples and launched under a single script.
   183   * Fixed mod_python native sessions.
   184   * Fixed Zope request stream access.
   185   * WebStack is now licensed under the LGPL - see docs/COPYING.txt for
   186     details.
   187 
   188 New in WebStack 0.8 (Changes since WebStack 0.7)
   189 ------------------------------------------------
   190 
   191   * Added a standard exception, EndOfResponse, which can be used to
   192     immediately stop the processing/production of a response; this is useful
   193     when resources need to issue a redirect without unnecessary content being
   194     generated, for example.
   195   * Fixed path information for Zope.
   196   * Added WSGI support.
   197   * Verified Twisted 1.3.0 support with Python 2.3.3.
   198 
   199 New in WebStack 0.7 (Changes since WebStack 0.6)
   200 ------------------------------------------------
   201 
   202   * Fixed path information semantics.
   203   * Fixed file upload semantics.
   204   * Fixed content type handling for Unicode output and for interpreting
   205     request body fields/parameters (although some improvement remains).
   206   * Added a method to discover the chosen response stream encoding.
   207   * Fixed field/parameter retrieval so that path and body fields are distinct,
   208     regardless of the framework employed.
   209   * Added a method to get a combination of path and body fields (suggested by
   210     Jacob Smullyan).
   211   * Introduced Zope 2 support.
   212   * Improved Jython/Java Servlet API support (although a special PyServlet
   213     class must now be used, and certain libraries must be deployed with
   214     applications).
   215   * Introduced authentication/authorisation support for Jython/Java Servlet
   216     API.
   217   * Session support has been added (except for Webware 0.8.1).
   218   * Alternative cookie support for mod_python has been added.
   219   * Cookie support now supports encoded Unicode sequences for names and
   220     values.
   221 
   222 New in WebStack 0.6 (Changes since WebStack 0.5)
   223 ------------------------------------------------
   224 
   225   * Introduced Jython/Java Servlet API support.
   226   * Minor fixes to example applications and to BaseHTTPRequestHandler.
   227 
   228 New in WebStack 0.5 (Changes since WebStack 0.4)
   229 ------------------------------------------------
   230 
   231   * Changed request body fields/parameters so that they are now represented
   232     using Unicode objects rather than plain strings.
   233   * Introduced better support for Unicode in response streams.
   234 
   235 New in WebStack 0.4 (Changes since WebStack 0.3)
   236 ------------------------------------------------
   237 
   238   * Added application definition of user identity, permitting alternative
   239     authentication mechanisms.
   240   * Improved BaseHTTPRequestHandler and mod_python reliability around fields
   241     from request bodies.
   242   * Provided stream and environment parameterisation in the CGI adapter.
   243   * Added LoginRedirect and Login examples.
   244   * Added get_path_without_query and fixed get_path behaviour.
   245 
   246 New in WebStack 0.3 (Changes since WebStack 0.2)
   247 ------------------------------------------------
   248 
   249   * Added better header support for Webware (suggested by Ian Bicking).
   250   * Introduced CGI and Java Servlet support (the latter is currently
   251     broken/unfinished).
   252   * Introduced support for cookies.
   253 
   254 Future Work
   255 -----------
   256 
   257 (Essential)
   258 
   259 Twisted 1.3.0 does not provide file upload metadata, and Twisted Web 0.5.0
   260 also seems to be missing this functionality. It isn't obvious whether Twisted
   261 Web2 will just copy its predecessors and provide a similarly limited API.
   262 Perhaps the Twisted support needs to resemble the CGI support much more when
   263 handling fields.
   264 
   265 JythonServlet libraries need to be configured using sys.add_package when
   266 these do not feature in the compiled-in list. Adding such configuration to
   267 the handler may be most appropriate (since the web.xml file can be too
   268 arcane), but this needs testing.
   269 
   270 The algorithm employed in the WebStack.Helpers.Auth.get_token function
   271 should be reviewed and improved for better security.
   272 
   273 (Important)
   274 
   275 Field access needs testing, especially for anything using the
   276 cgi.FieldStorage class, and the way file uploads are exposed should be
   277 reviewed (currently the meta-data is not exposed). The acquisition of fields
   278 from specific sources should be tested with different request methods - some
   279 frameworks provide path fields in the body fields dictionary, others (eg.
   280 Zope) change the fields exposed depending on request method.
   281 
   282 Interpretation of path field encodings needs to be verified. Currently,
   283 stray path fields are handled (eg. in WebStack.Helpers.Request) as being
   284 ISO-8859-1, but it might be the case that some such fields might be
   285 submitted as UTF-8. The decode_path method on Transaction does do much of the
   286 work that is likely to be required, however. Still, a good policy for decoding
   287 path fields, reducing the number of times one might specify the encoding in
   288 various method calls, may be important.
   289 
   290 An interesting test of encodings is to introduce things like the following to
   291 the path info and query string sections of the URL: %25F0?%E6=%F8&%25F0=%F8
   292 This should produce the following decoded result: %F0?æ=ø&%F0=ø
   293 (The above needs to be read in ISO-8859-1 or ISO-8859-15.)
   294 
   295 Cookie objects need defining strictly, especially since the standard library
   296 Cookie object behaves differently to mod_python (and possibly Webware)
   297 Cookie objects. Moreover, the set_cookie_value method needs to provide
   298 access to the usual cookie parameters as supported by the frameworks. The
   299 standard library Cookie module has issues with Unicode cookie names (and
   300 possibly values) - this is worked around, but it would be best to resolve
   301 this comprehensively.
   302 
   303 UTF-16 (and possibly other encodings) causes problems with HTML form data
   304 sent in POST requests using the application/x-www-form-urlencoded content
   305 type.  This should be reviewed at a later date when proper standardisation
   306 has taken place.
   307 
   308 Session support, especially through WebStack.Helpers.Session, should be
   309 reviewed and be made compatible with non-cookie mechanisms.
   310 
   311 Locking in the session support and in DirectoryRepository should be improved.
   312 
   313 HeaderValue objects should be employed more extensively. Thus, the header
   314 access methods may need to change their behaviour slightly. The get_headers
   315 method should potentially return a list for each item in the dictionary.
   316 
   317 WSGI support could demand that a special "end of headers" method be
   318 introduced into WebStack, thus making response output more efficient (and
   319 probably also for other frameworks, too).
   320 
   321 Investigate proper support for HEAD, OPTIONS and other request methods.
   322 
   323 Consider packages for different operating systems (other than Debian).
   324 
   325 Investigate cStringIO usage.
   326 
   327 The location of deployed applications in the filesystem should be exposed to
   328 those applications. (This is actually available in the __file__ module
   329 variable.) A resource could be provided to record the "root" path and added to
   330 a resource hierarchy or site map. Note that PathSelector records the "root"
   331 path, although it is not automatically deployed.
   332 
   333 (Completed/rejected)
   334 
   335 Path information should be consistent across all frameworks, and the "path
   336 info" value should be meaningful. (This should now be correct.)
   337 
   338 Investigate the nicer functions in the cgi module, discarding the "magic"
   339 stuff like FieldStorage. (These nicer functions are used by projects like
   340 Twisted - as of 1.3.0 at least - and do not give the necessary information we
   341 require.)
   342 
   343 Release Procedures
   344 ------------------
   345 
   346 Update the WebStack/__init__.py __version__ attribute.
   347 Change the version number and package filename/directory in the documentation.
   348 Change code examples in the documentation if appropriate.
   349 Update the release notes (see above).
   350 Check the setup.py file and ensure that all package directories are mentioned.
   351 Check the release information in the PKG-INFO file and in the package
   352 changelog (and other files).
   353 Tag, export.
   354 Generate the PyServlet classes.
   355 Generate the API documentation.
   356 Remove generated .pyc files: rm `find . -name "*.pyc"`
   357 Archive, upload.
   358 Upload the introductory documentation.
   359 Update PyPI, PythonInfo Wiki, Vaults of Parnassus entries.
   360 
   361 Generating the API Documentation
   362 --------------------------------
   363 
   364 In order to prepare the API documentation, it is necessary to generate some
   365 Web pages from the Python source code. For this, the epydoc application must
   366 be available on your system. Then, inside the distribution directory, run the
   367 apidocs.sh tool script as follows:
   368 
   369 ./tools/apidocs.sh
   370 
   371 Some warnings may be generated by the script, but the result should be a new
   372 apidocs directory within the distribution directory.
   373 
   374 Making Packages
   375 ---------------
   376 
   377 To make Debian-based packages:
   378 
   379   1. Create new package directories under packages if necessary.
   380   2. Make a symbolic link in the distribution's root directory to keep the
   381      Debian tools happy:
   382 
   383      ln -s packages/ubuntu-hoary/python2.4-webstack/debian/
   384 
   385   3. Run the package builder:
   386 
   387      dpkg-buildpackage -rfakeroot
   388 
   389   4. Locate and tidy up the packages in the parent directory of the
   390      distribution's root directory.