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