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