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 Jython/Java Servlet API Jython 2.1, Java JDK 1.3.1_02, Tomcat 4.1.31 (Servlet 2.3)
49 mod_python 3.0.3 (3.1.3 for framework cookie and session support)
50 Twisted 1.0.5, 1.3.0
51 Webware 0.8.1, CVS (2004-02-06), 0.9b2
52 WSGI run_with_cgi (PEP 333)
53 Zope 2.7.2-0, 2.8.0-final
54
55 New in WebStack 1.1 (Changes since WebStack 1.0)
56 ------------------------------------------------
57
58 * Added a Repositories package to provide session-like support for
59 different kinds of storage.
60 * Added an explicit filesystem encoding to the Calendar example and adopted
61 the DirectoryRepository from the Repositories package.
62 * Added get_path_without_info, update_path and redirect methods to the
63 Transaction class.
64 * Added get_attributes (attribute support) to the Transaction class.
65 * Added a values method to Helpers.Session.Wrapper.
66 * Fixed get_processed_virtual_path_info (to match from right to left).
67 * Improved/fixed exception handling in the adapters so that transactions are
68 committed as the final act of an adapter experiencing an unhandled
69 exception. This should result in session stores being closed properly.
70 * Changed the Helpers.Session.SessionStore to use DirectoryRepository.
71 * Made the "not found" behaviour of DirectoryResource more configurable.
72 * Added documentation for MapResource and DirectoryResource.
73 * Fixed the distribution names in the Ubuntu changelog.
74
75 New in WebStack 1.0 (Changes since WebStack 0.10)
76 -------------------------------------------------
77
78 * Changed the behaviour of get_path, get_path_without_query, get_path_info,
79 get_virtual_path_info, get_processed_virtual_path_info and
80 get_fields_from_path to return Unicode data decoded using the optional
81 encoding parameter or a common default encoding.
82 * Fixed file upload values so that FileContent objects are returned for such
83 fields in get_fields_from_body and get_fields.
84 (Warning! Except for Twisted!)
85 * Fixed the JavaServlet support so that streams and file content are
86 obtained as "almost" plain strings.
87 * Updated/fixed LoginResource and LoginRedirectResource to use the updated
88 path API and to handle special characters properly.
89 * Added convenience methods to Transaction for the decoding and encoding of
90 path values (to and from Unicode objects) - see the decode_path and
91 encode_path methods.
92 * Added the notion of processed virtual path info - the part of the original
93 path info not represented in the current virtual path info.
94 * Added "pass through" behaviour to ResourceMap.MapResource (prompted by a
95 patch from Scott Robinson).
96 * Fixed ResourceMap.MapResource to handle non-existent resources properly
97 (where the virtual path info is only one component in length).
98 * Added Debian package support.
99 * Added automatic session directory creation for the WebStack sessions
100 implementation.
101 * Added support for the repeated retrieval of sessions from the same
102 WebStack session store, avoiding deadlocks.
103 * Fixed the calendar example, making it perform a proper function.
104 * Made the BaseHTTPRequestHandler and Twisted SimpleWithLogin applications
105 include the Login application, since Konqueror (at least) does not share
106 cookies across different port numbers on the same host.
107 * Added the SimpleWithLogin and Login applications to the demonstration.
108 * Improved the documentation, adding information on request headers, and
109 describing file upload and session support limitations.
110 * Improved the AOLserver-related notes for CGI and Webware, adding a patch
111 for Webware in order to work around AOLserver issues.
112
113 New in WebStack 0.10 (Changes since WebStack 0.9)
114 -------------------------------------------------
115
116 * Changes to make the tools/demo.py script work on Windows (and other)
117 platforms (suggested by Jim Madsen).
118 * Fixed end of header newlines for CGI (suggested by Matt Harrison).
119 * Minor documentation fixes and improvements, adding information on
120 AOLserver in the CGI and Webware notes.
121 * Changed the mod_python server name method to use the server object rather
122 than the connection object.
123 * Added a parameter to the ResourceMap.MapResource class to permit automatic
124 redirects into resource hierarchies when no trailing "/" was given in the
125 URL; changed the updated virtual path info so that empty values may be set
126 (the guarantee that "/" will always appear no longer applies).
127 * Fixed virtual path info retrieval when the value is an empty string.
128
129 New in WebStack 0.9 (Changes since WebStack 0.8)
130 ------------------------------------------------
131
132 * Standardised error handling in the adapters so that tracebacks can be
133 suppressed and an internal server error condition raised.
134 * Added overriding of path info in transactions.
135 * Added a ResourceMap resource for dispatching to different resources
136 according to path components.
137 * Standardised deployment for some frameworks (see docs/deploying.html).
138 * Introductory documentation in XHTML format.
139 * Added server name and port methods to the transaction.
140 * Added a simple demonstration application, incorporating many of the
141 examples and launched under a single script.
142 * Fixed mod_python native sessions.
143 * Fixed Zope request stream access.
144 * WebStack is now licensed under the LGPL - see docs/COPYING.txt for
145 details.
146
147 New in WebStack 0.8 (Changes since WebStack 0.7)
148 ------------------------------------------------
149
150 * Added a standard exception, EndOfResponse, which can be used to
151 immediately stop the processing/production of a response; this is useful
152 when resources need to issue a redirect without unnecessary content being
153 generated, for example.
154 * Fixed path information for Zope.
155 * Added WSGI support.
156 * Verified Twisted 1.3.0 support with Python 2.3.3.
157
158 New in WebStack 0.7 (Changes since WebStack 0.6)
159 ------------------------------------------------
160
161 * Fixed path information semantics.
162 * Fixed file upload semantics.
163 * Fixed content type handling for Unicode output and for interpreting
164 request body fields/parameters (although some improvement remains).
165 * Added a method to discover the chosen response stream encoding.
166 * Fixed field/parameter retrieval so that path and body fields are distinct,
167 regardless of the framework employed.
168 * Added a method to get a combination of path and body fields (suggested by
169 Jacob Smullyan).
170 * Introduced Zope 2 support.
171 * Improved Jython/Java Servlet API support (although a special PyServlet
172 class must now be used, and certain libraries must be deployed with
173 applications).
174 * Introduced authentication/authorisation support for Jython/Java Servlet
175 API.
176 * Session support has been added (except for Webware 0.8.1).
177 * Alternative cookie support for mod_python has been added.
178 * Cookie support now supports encoded Unicode sequences for names and
179 values.
180
181 New in WebStack 0.6 (Changes since WebStack 0.5)
182 ------------------------------------------------
183
184 * Introduced Jython/Java Servlet API support.
185 * Minor fixes to example applications and to BaseHTTPRequestHandler.
186
187 New in WebStack 0.5 (Changes since WebStack 0.4)
188 ------------------------------------------------
189
190 * Changed request body fields/parameters so that they are now represented
191 using Unicode objects rather than plain strings.
192 * Introduced better support for Unicode in response streams.
193
194 New in WebStack 0.4 (Changes since WebStack 0.3)
195 ------------------------------------------------
196
197 * Added application definition of user identity, permitting alternative
198 authentication mechanisms.
199 * Improved BaseHTTPRequestHandler and mod_python reliability around fields
200 from request bodies.
201 * Provided stream and environment parameterisation in the CGI adapter.
202 * Added LoginRedirect and Login examples.
203 * Added get_path_without_query and fixed get_path behaviour.
204
205 New in WebStack 0.3 (Changes since WebStack 0.2)
206 ------------------------------------------------
207
208 * Added better header support for Webware (suggested by Ian Bicking).
209 * Introduced CGI and Java Servlet support (the latter is currently
210 broken/unfinished).
211 * Introduced support for cookies.
212
213 Future Work
214 -----------
215
216 (Essential)
217
218 Twisted 1.3.0 does not provide file upload metadata, and Twisted Web 0.5.0
219 also seems to be missing this functionality. It isn't obvious whether Twisted
220 Web2 will just copy its predecessors and provide a similarly limited API.
221 Perhaps the Twisted support needs to resemble the CGI support much more when
222 handling fields.
223
224 JythonServlet libraries need to be configured using sys.add_package when
225 these do not feature in the compiled-in list. Adding such configuration to
226 the handler may be most appropriate (since the web.xml file can be too
227 arcane), but this needs testing.
228
229 (Important)
230
231 Field access needs testing, especially for anything using the
232 cgi.FieldStorage class, and the way file uploads are exposed should be
233 reviewed (currently the meta-data is not exposed). The acquisition of fields
234 from specific sources should be tested with different request methods - some
235 frameworks provide path fields in the body fields dictionary, others (eg.
236 Zope) change the fields exposed depending on request method.
237
238 Interpretation of path field encodings needs to be verified. Currently,
239 stray path fields are handled (eg. in WebStack.Helpers.Request) as being
240 ISO-8859-1, but it might be the case that some such fields might be
241 submitted as UTF-8. The decode_path method on Transaction does do much of the
242 work that is likely to be required, however. Still, a good policy for decoding
243 path fields, reducing the number of times one might specify the encoding in
244 various method calls, may be important.
245
246 An interesting test of encodings is to introduce things like the following to
247 the path info and query string sections of the URL: %25F0?%E6=%F8&%25F0=%F8
248 This should produce the following decoded result: %F0?æ=ø&%F0=ø
249 (The above needs to be read in ISO-8859-1 or ISO-8859-15.)
250
251 Cookie objects need defining strictly, especially since the standard library
252 Cookie object behaves differently to mod_python (and possibly Webware)
253 Cookie objects. Moreover, the set_cookie_value method needs to provide
254 access to the usual cookie parameters as supported by the frameworks. The
255 standard library Cookie module has issues with Unicode cookie names (and
256 possibly values) - this is worked around, but it would be best to resolve
257 this comprehensively.
258
259 UTF-16 (and possibly other encodings) causes problems with HTML form data
260 sent in POST requests using the application/x-www-form-urlencoded content
261 type. This should be reviewed at a later date when proper standardisation
262 has taken place.
263
264 Session support, especially through WebStack.Helpers.Session, should be
265 reviewed and be made compatible with non-cookie mechanisms.
266
267 Locking in the session support and in DirectoryRepository should be improved.
268
269 HeaderValue objects should be employed more extensively. Thus, the header
270 access methods may need to change their behaviour slightly. The get_headers
271 method should potentially return a list for each item in the dictionary.
272
273 WSGI support could demand that a special "end of headers" method be
274 introduced into WebStack, thus making response output more efficient (and
275 probably also for other frameworks, too).
276
277 The algorithm employed in the WebStack.Helpers.Auth.get_token function
278 should be reviewed and improved for better security.
279
280 Investigate proper support for HEAD, OPTIONS and other request methods.
281
282 Consider packages for different operating systems (other than Debian).
283
284 Provide some 500 error content when handle_errors is true.
285
286 (Completed/rejected)
287
288 The location of deployed applications in the filesystem should be exposed to
289 those applications. (This is actually available in the __file__ module
290 variable.)
291
292 Path information should be consistent across all frameworks, and the "path
293 info" value should be meaningful. (This should now be correct.)
294
295 Investigate the nicer functions in the cgi module, discarding the "magic"
296 stuff like FieldStorage. (These nicer functions are used by projects like
297 Twisted - as of 1.3.0 at least - and do not give the necessary information we
298 require.)
299
300 Release Procedures
301 ------------------
302
303 Update the WebStack/__init__.py __version__ attribute.
304 Change the version number and package filename/directory in the documentation.
305 Change code examples in the documentation if appropriate.
306 Update the release notes (see above).
307 Check the setup.py file and ensure that all package directories are mentioned.
308 Check the release information in the PKG-INFO file and in the package
309 changelog (and other files).
310 Tag, export.
311 Generate the PyServlet classes.
312 Generate the API documentation.
313 Remove generated .pyc files: rm `find . -name "*.pyc"`
314 Archive, upload.
315 Upload the introductory documentation.
316 Update PyPI, PythonInfo Wiki, Vaults of Parnassus entries.
317
318 Generating the API Documentation
319 --------------------------------
320
321 In order to prepare the API documentation, it is necessary to generate some
322 Web pages from the Python source code. For this, the epydoc application must
323 be available on your system. Then, inside the distribution directory, run the
324 apidocs.sh tool script as follows:
325
326 ./tools/apidocs.sh
327
328 Some warnings may be generated by the script, but the result should be a new
329 apidocs directory within the distribution directory.
330
331 Making Packages
332 ---------------
333
334 To make Debian-based packages:
335
336 1. Create new package directories under packages if necessary.
337 2. Make a symbolic link in the distribution's root directory to keep the
338 Debian tools happy:
339
340 ln -s packages/ubuntu-hoary/python2.4-webstack/debian/
341
342 3. Run the package builder:
343
344 dpkg-buildpackage -rfakeroot
345
346 4. Locate and tidy up the packages in the parent directory of the
347 distribution's root directory.