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