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 Currently, BaseHTTPRequestHandler (via BaseHTTPServer in the standard
36 library), CGI, Jython/Java Servlet API, mod_python, Twisted, Webware, WSGI
37 and Zope 2 are supported. Each framework has its own set of strengths and
38 weaknesses, but the idea is that deployment concerns can be considered
39 separately from the implementation of application functionality. Consult the
40 NOTES.txt files in each framework's subdirectory of the docs directory for
41 some notes on how applications may be run in each environment.
42
43 Tested Frameworks Release Information
44 ----------------- -------------------
45
46 BaseHTTPRequestHandler Python 2.2.2, Python 2.3.3, Python 2.4.1
47 CGI Apache 2.0.44, Apache 2.0.53, AOLserver 4.0.10, lighttpd 1.3.15
48 Django 0.91
49 Jython/Java Servlet API Jython 2.1, Java JDK 1.3.1_02, Tomcat 4.1.31 (Servlet 2.3)
50 mod_python 3.0.3 (3.1.3 for framework cookie and session support)
51 Twisted 1.0.5, 1.3.0
52 Webware 0.8.1, CVS (2004-02-06), 0.9b2
53 WSGI run_with_cgi (PEP 333)
54 Zope 2.7.2-0, 2.8.0-final
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 * Improved mod_python deployment documentation and tools so that cleaner
62 application paths/URLs can now be used.
63 * Moved user and path_info default definitions into WebStack.Generic as
64 class attributes.
65 * Fixed encoding usage issues with path fields when using get_fields in a
66 Zope environment.
67 * Added a FileResource class to WebStack.Resources.Static.
68
69 New in WebStack 1.1.2 (Changes since WebStack 1.1.1)
70 ----------------------------------------------------
71
72 * Fixed missing import in WebStack.Repositories.Directory.
73
74 New in WebStack 1.1.1 (Changes since WebStack 1.1)
75 --------------------------------------------------
76
77 * Fixed update_path to handle the root path properly.
78
79 New in WebStack 1.1 (Changes since WebStack 1.0)
80 ------------------------------------------------
81
82 * Added a Repositories package to provide session-like support for
83 different kinds of storage.
84 * Added an explicit filesystem encoding to the Calendar example and adopted
85 the DirectoryRepository from the Repositories package.
86 * Added get_path_without_info, update_path and redirect methods to the
87 Transaction class.
88 * Added get_attributes (attribute support) to the Transaction class.
89 * Added a values method to Helpers.Session.Wrapper.
90 * Fixed get_processed_virtual_path_info (to match from right to left).
91 * Improved/fixed exception handling in the adapters so that transactions are
92 committed as the final act of an adapter experiencing an unhandled
93 exception. This should result in session stores being closed properly.
94 * Changed the Helpers.Session.SessionStore to use DirectoryRepository.
95 * Made the "not found" behaviour of DirectoryResource more configurable.
96 * Added documentation for MapResource and DirectoryResource.
97 * Fixed the distribution names in the Ubuntu changelog.
98
99 New in WebStack 1.0 (Changes since WebStack 0.10)
100 -------------------------------------------------
101
102 * Changed the behaviour of get_path, get_path_without_query, get_path_info,
103 get_virtual_path_info, get_processed_virtual_path_info and
104 get_fields_from_path to return Unicode data decoded using the optional
105 encoding parameter or a common default encoding.
106 * Fixed file upload values so that FileContent objects are returned for such
107 fields in get_fields_from_body and get_fields.
108 (Warning! Except for Twisted!)
109 * Fixed the JavaServlet support so that streams and file content are
110 obtained as "almost" plain strings.
111 * Updated/fixed LoginResource and LoginRedirectResource to use the updated
112 path API and to handle special characters properly.
113 * Added convenience methods to Transaction for the decoding and encoding of
114 path values (to and from Unicode objects) - see the decode_path and
115 encode_path methods.
116 * Added the notion of processed virtual path info - the part of the original
117 path info not represented in the current virtual path info.
118 * Added "pass through" behaviour to ResourceMap.MapResource (prompted by a
119 patch from Scott Robinson).
120 * Fixed ResourceMap.MapResource to handle non-existent resources properly
121 (where the virtual path info is only one component in length).
122 * Added Debian package support.
123 * Added automatic session directory creation for the WebStack sessions
124 implementation.
125 * Added support for the repeated retrieval of sessions from the same
126 WebStack session store, avoiding deadlocks.
127 * Fixed the calendar example, making it perform a proper function.
128 * Made the BaseHTTPRequestHandler and Twisted SimpleWithLogin applications
129 include the Login application, since Konqueror (at least) does not share
130 cookies across different port numbers on the same host.
131 * Added the SimpleWithLogin and Login applications to the demonstration.
132 * Improved the documentation, adding information on request headers, and
133 describing file upload and session support limitations.
134 * Improved the AOLserver-related notes for CGI and Webware, adding a patch
135 for Webware in order to work around AOLserver issues.
136
137 New in WebStack 0.10 (Changes since WebStack 0.9)
138 -------------------------------------------------
139
140 * Changes to make the tools/demo.py script work on Windows (and other)
141 platforms (suggested by Jim Madsen).
142 * Fixed end of header newlines for CGI (suggested by Matt Harrison).
143 * Minor documentation fixes and improvements, adding information on
144 AOLserver in the CGI and Webware notes.
145 * Changed the mod_python server name method to use the server object rather
146 than the connection object.
147 * Added a parameter to the ResourceMap.MapResource class to permit automatic
148 redirects into resource hierarchies when no trailing "/" was given in the
149 URL; changed the updated virtual path info so that empty values may be set
150 (the guarantee that "/" will always appear no longer applies).
151 * Fixed virtual path info retrieval when the value is an empty string.
152
153 New in WebStack 0.9 (Changes since WebStack 0.8)
154 ------------------------------------------------
155
156 * Standardised error handling in the adapters so that tracebacks can be
157 suppressed and an internal server error condition raised.
158 * Added overriding of path info in transactions.
159 * Added a ResourceMap resource for dispatching to different resources
160 according to path components.
161 * Standardised deployment for some frameworks (see docs/deploying.html).
162 * Introductory documentation in XHTML format.
163 * Added server name and port methods to the transaction.
164 * Added a simple demonstration application, incorporating many of the
165 examples and launched under a single script.
166 * Fixed mod_python native sessions.
167 * Fixed Zope request stream access.
168 * WebStack is now licensed under the LGPL - see docs/COPYING.txt for
169 details.
170
171 New in WebStack 0.8 (Changes since WebStack 0.7)
172 ------------------------------------------------
173
174 * Added a standard exception, EndOfResponse, which can be used to
175 immediately stop the processing/production of a response; this is useful
176 when resources need to issue a redirect without unnecessary content being
177 generated, for example.
178 * Fixed path information for Zope.
179 * Added WSGI support.
180 * Verified Twisted 1.3.0 support with Python 2.3.3.
181
182 New in WebStack 0.7 (Changes since WebStack 0.6)
183 ------------------------------------------------
184
185 * Fixed path information semantics.
186 * Fixed file upload semantics.
187 * Fixed content type handling for Unicode output and for interpreting
188 request body fields/parameters (although some improvement remains).
189 * Added a method to discover the chosen response stream encoding.
190 * Fixed field/parameter retrieval so that path and body fields are distinct,
191 regardless of the framework employed.
192 * Added a method to get a combination of path and body fields (suggested by
193 Jacob Smullyan).
194 * Introduced Zope 2 support.
195 * Improved Jython/Java Servlet API support (although a special PyServlet
196 class must now be used, and certain libraries must be deployed with
197 applications).
198 * Introduced authentication/authorisation support for Jython/Java Servlet
199 API.
200 * Session support has been added (except for Webware 0.8.1).
201 * Alternative cookie support for mod_python has been added.
202 * Cookie support now supports encoded Unicode sequences for names and
203 values.
204
205 New in WebStack 0.6 (Changes since WebStack 0.5)
206 ------------------------------------------------
207
208 * Introduced Jython/Java Servlet API support.
209 * Minor fixes to example applications and to BaseHTTPRequestHandler.
210
211 New in WebStack 0.5 (Changes since WebStack 0.4)
212 ------------------------------------------------
213
214 * Changed request body fields/parameters so that they are now represented
215 using Unicode objects rather than plain strings.
216 * Introduced better support for Unicode in response streams.
217
218 New in WebStack 0.4 (Changes since WebStack 0.3)
219 ------------------------------------------------
220
221 * Added application definition of user identity, permitting alternative
222 authentication mechanisms.
223 * Improved BaseHTTPRequestHandler and mod_python reliability around fields
224 from request bodies.
225 * Provided stream and environment parameterisation in the CGI adapter.
226 * Added LoginRedirect and Login examples.
227 * Added get_path_without_query and fixed get_path behaviour.
228
229 New in WebStack 0.3 (Changes since WebStack 0.2)
230 ------------------------------------------------
231
232 * Added better header support for Webware (suggested by Ian Bicking).
233 * Introduced CGI and Java Servlet support (the latter is currently
234 broken/unfinished).
235 * Introduced support for cookies.
236
237 Future Work
238 -----------
239
240 (Essential)
241
242 Twisted 1.3.0 does not provide file upload metadata, and Twisted Web 0.5.0
243 also seems to be missing this functionality. It isn't obvious whether Twisted
244 Web2 will just copy its predecessors and provide a similarly limited API.
245 Perhaps the Twisted support needs to resemble the CGI support much more when
246 handling fields.
247
248 JythonServlet libraries need to be configured using sys.add_package when
249 these do not feature in the compiled-in list. Adding such configuration to
250 the handler may be most appropriate (since the web.xml file can be too
251 arcane), but this needs testing.
252
253 (Important)
254
255 Field access needs testing, especially for anything using the
256 cgi.FieldStorage class, and the way file uploads are exposed should be
257 reviewed (currently the meta-data is not exposed). The acquisition of fields
258 from specific sources should be tested with different request methods - some
259 frameworks provide path fields in the body fields dictionary, others (eg.
260 Zope) change the fields exposed depending on request method.
261
262 Interpretation of path field encodings needs to be verified. Currently,
263 stray path fields are handled (eg. in WebStack.Helpers.Request) as being
264 ISO-8859-1, but it might be the case that some such fields might be
265 submitted as UTF-8. The decode_path method on Transaction does do much of the
266 work that is likely to be required, however. Still, a good policy for decoding
267 path fields, reducing the number of times one might specify the encoding in
268 various method calls, may be important.
269
270 An interesting test of encodings is to introduce things like the following to
271 the path info and query string sections of the URL: %25F0?%E6=%F8&%25F0=%F8
272 This should produce the following decoded result: %F0?æ=ø&%F0=ø
273 (The above needs to be read in ISO-8859-1 or ISO-8859-15.)
274
275 Cookie objects need defining strictly, especially since the standard library
276 Cookie object behaves differently to mod_python (and possibly Webware)
277 Cookie objects. Moreover, the set_cookie_value method needs to provide
278 access to the usual cookie parameters as supported by the frameworks. The
279 standard library Cookie module has issues with Unicode cookie names (and
280 possibly values) - this is worked around, but it would be best to resolve
281 this comprehensively.
282
283 UTF-16 (and possibly other encodings) causes problems with HTML form data
284 sent in POST requests using the application/x-www-form-urlencoded content
285 type. This should be reviewed at a later date when proper standardisation
286 has taken place.
287
288 Session support, especially through WebStack.Helpers.Session, should be
289 reviewed and be made compatible with non-cookie mechanisms.
290
291 Locking in the session support and in DirectoryRepository should be improved.
292
293 HeaderValue objects should be employed more extensively. Thus, the header
294 access methods may need to change their behaviour slightly. The get_headers
295 method should potentially return a list for each item in the dictionary.
296
297 WSGI support could demand that a special "end of headers" method be
298 introduced into WebStack, thus making response output more efficient (and
299 probably also for other frameworks, too).
300
301 The algorithm employed in the WebStack.Helpers.Auth.get_token function
302 should be reviewed and improved for better security.
303
304 Investigate proper support for HEAD, OPTIONS and other request methods.
305
306 Consider packages for different operating systems (other than Debian).
307
308 Provide some 500 error content when handle_errors is true.
309
310 Investigate cStringIO usage.
311
312 (Completed/rejected)
313
314 The location of deployed applications in the filesystem should be exposed to
315 those applications. (This is actually available in the __file__ module
316 variable.)
317
318 Path information should be consistent across all frameworks, and the "path
319 info" value should be meaningful. (This should now be correct.)
320
321 Investigate the nicer functions in the cgi module, discarding the "magic"
322 stuff like FieldStorage. (These nicer functions are used by projects like
323 Twisted - as of 1.3.0 at least - and do not give the necessary information we
324 require.)
325
326 Release Procedures
327 ------------------
328
329 Update the WebStack/__init__.py __version__ attribute.
330 Change the version number and package filename/directory in the documentation.
331 Change code examples in the documentation if appropriate.
332 Update the release notes (see above).
333 Check the setup.py file and ensure that all package directories are mentioned.
334 Check the release information in the PKG-INFO file and in the package
335 changelog (and other files).
336 Tag, export.
337 Generate the PyServlet classes.
338 Generate the API documentation.
339 Remove generated .pyc files: rm `find . -name "*.pyc"`
340 Archive, upload.
341 Upload the introductory documentation.
342 Update PyPI, PythonInfo Wiki, Vaults of Parnassus entries.
343
344 Generating the API Documentation
345 --------------------------------
346
347 In order to prepare the API documentation, it is necessary to generate some
348 Web pages from the Python source code. For this, the epydoc application must
349 be available on your system. Then, inside the distribution directory, run the
350 apidocs.sh tool script as follows:
351
352 ./tools/apidocs.sh
353
354 Some warnings may be generated by the script, but the result should be a new
355 apidocs directory within the distribution directory.
356
357 Making Packages
358 ---------------
359
360 To make Debian-based packages:
361
362 1. Create new package directories under packages if necessary.
363 2. Make a symbolic link in the distribution's root directory to keep the
364 Debian tools happy:
365
366 ln -s packages/ubuntu-hoary/python2.4-webstack/debian/
367
368 3. Run the package builder:
369
370 dpkg-buildpackage -rfakeroot
371
372 4. Locate and tidy up the packages in the parent directory of the
373 distribution's root directory.