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 1.1.1 (Changes since WebStack 1.1)
56 --------------------------------------------------
57
58 * Fixed update_path to handle the root path properly.
59
60 New in WebStack 1.1 (Changes since WebStack 1.0)
61 ------------------------------------------------
62
63 * Added a Repositories package to provide session-like support for
64 different kinds of storage.
65 * Added an explicit filesystem encoding to the Calendar example and adopted
66 the DirectoryRepository from the Repositories package.
67 * Added get_path_without_info, update_path and redirect methods to the
68 Transaction class.
69 * Added get_attributes (attribute support) to the Transaction class.
70 * Added a values method to Helpers.Session.Wrapper.
71 * Fixed get_processed_virtual_path_info (to match from right to left).
72 * Improved/fixed exception handling in the adapters so that transactions are
73 committed as the final act of an adapter experiencing an unhandled
74 exception. This should result in session stores being closed properly.
75 * Changed the Helpers.Session.SessionStore to use DirectoryRepository.
76 * Made the "not found" behaviour of DirectoryResource more configurable.
77 * Added documentation for MapResource and DirectoryResource.
78 * Fixed the distribution names in the Ubuntu changelog.
79
80 New in WebStack 1.0 (Changes since WebStack 0.10)
81 -------------------------------------------------
82
83 * Changed the behaviour of get_path, get_path_without_query, get_path_info,
84 get_virtual_path_info, get_processed_virtual_path_info and
85 get_fields_from_path to return Unicode data decoded using the optional
86 encoding parameter or a common default encoding.
87 * Fixed file upload values so that FileContent objects are returned for such
88 fields in get_fields_from_body and get_fields.
89 (Warning! Except for Twisted!)
90 * Fixed the JavaServlet support so that streams and file content are
91 obtained as "almost" plain strings.
92 * Updated/fixed LoginResource and LoginRedirectResource to use the updated
93 path API and to handle special characters properly.
94 * Added convenience methods to Transaction for the decoding and encoding of
95 path values (to and from Unicode objects) - see the decode_path and
96 encode_path methods.
97 * Added the notion of processed virtual path info - the part of the original
98 path info not represented in the current virtual path info.
99 * Added "pass through" behaviour to ResourceMap.MapResource (prompted by a
100 patch from Scott Robinson).
101 * Fixed ResourceMap.MapResource to handle non-existent resources properly
102 (where the virtual path info is only one component in length).
103 * Added Debian package support.
104 * Added automatic session directory creation for the WebStack sessions
105 implementation.
106 * Added support for the repeated retrieval of sessions from the same
107 WebStack session store, avoiding deadlocks.
108 * Fixed the calendar example, making it perform a proper function.
109 * Made the BaseHTTPRequestHandler and Twisted SimpleWithLogin applications
110 include the Login application, since Konqueror (at least) does not share
111 cookies across different port numbers on the same host.
112 * Added the SimpleWithLogin and Login applications to the demonstration.
113 * Improved the documentation, adding information on request headers, and
114 describing file upload and session support limitations.
115 * Improved the AOLserver-related notes for CGI and Webware, adding a patch
116 for Webware in order to work around AOLserver issues.
117
118 New in WebStack 0.10 (Changes since WebStack 0.9)
119 -------------------------------------------------
120
121 * Changes to make the tools/demo.py script work on Windows (and other)
122 platforms (suggested by Jim Madsen).
123 * Fixed end of header newlines for CGI (suggested by Matt Harrison).
124 * Minor documentation fixes and improvements, adding information on
125 AOLserver in the CGI and Webware notes.
126 * Changed the mod_python server name method to use the server object rather
127 than the connection object.
128 * Added a parameter to the ResourceMap.MapResource class to permit automatic
129 redirects into resource hierarchies when no trailing "/" was given in the
130 URL; changed the updated virtual path info so that empty values may be set
131 (the guarantee that "/" will always appear no longer applies).
132 * Fixed virtual path info retrieval when the value is an empty string.
133
134 New in WebStack 0.9 (Changes since WebStack 0.8)
135 ------------------------------------------------
136
137 * Standardised error handling in the adapters so that tracebacks can be
138 suppressed and an internal server error condition raised.
139 * Added overriding of path info in transactions.
140 * Added a ResourceMap resource for dispatching to different resources
141 according to path components.
142 * Standardised deployment for some frameworks (see docs/deploying.html).
143 * Introductory documentation in XHTML format.
144 * Added server name and port methods to the transaction.
145 * Added a simple demonstration application, incorporating many of the
146 examples and launched under a single script.
147 * Fixed mod_python native sessions.
148 * Fixed Zope request stream access.
149 * WebStack is now licensed under the LGPL - see docs/COPYING.txt for
150 details.
151
152 New in WebStack 0.8 (Changes since WebStack 0.7)
153 ------------------------------------------------
154
155 * Added a standard exception, EndOfResponse, which can be used to
156 immediately stop the processing/production of a response; this is useful
157 when resources need to issue a redirect without unnecessary content being
158 generated, for example.
159 * Fixed path information for Zope.
160 * Added WSGI support.
161 * Verified Twisted 1.3.0 support with Python 2.3.3.
162
163 New in WebStack 0.7 (Changes since WebStack 0.6)
164 ------------------------------------------------
165
166 * Fixed path information semantics.
167 * Fixed file upload semantics.
168 * Fixed content type handling for Unicode output and for interpreting
169 request body fields/parameters (although some improvement remains).
170 * Added a method to discover the chosen response stream encoding.
171 * Fixed field/parameter retrieval so that path and body fields are distinct,
172 regardless of the framework employed.
173 * Added a method to get a combination of path and body fields (suggested by
174 Jacob Smullyan).
175 * Introduced Zope 2 support.
176 * Improved Jython/Java Servlet API support (although a special PyServlet
177 class must now be used, and certain libraries must be deployed with
178 applications).
179 * Introduced authentication/authorisation support for Jython/Java Servlet
180 API.
181 * Session support has been added (except for Webware 0.8.1).
182 * Alternative cookie support for mod_python has been added.
183 * Cookie support now supports encoded Unicode sequences for names and
184 values.
185
186 New in WebStack 0.6 (Changes since WebStack 0.5)
187 ------------------------------------------------
188
189 * Introduced Jython/Java Servlet API support.
190 * Minor fixes to example applications and to BaseHTTPRequestHandler.
191
192 New in WebStack 0.5 (Changes since WebStack 0.4)
193 ------------------------------------------------
194
195 * Changed request body fields/parameters so that they are now represented
196 using Unicode objects rather than plain strings.
197 * Introduced better support for Unicode in response streams.
198
199 New in WebStack 0.4 (Changes since WebStack 0.3)
200 ------------------------------------------------
201
202 * Added application definition of user identity, permitting alternative
203 authentication mechanisms.
204 * Improved BaseHTTPRequestHandler and mod_python reliability around fields
205 from request bodies.
206 * Provided stream and environment parameterisation in the CGI adapter.
207 * Added LoginRedirect and Login examples.
208 * Added get_path_without_query and fixed get_path behaviour.
209
210 New in WebStack 0.3 (Changes since WebStack 0.2)
211 ------------------------------------------------
212
213 * Added better header support for Webware (suggested by Ian Bicking).
214 * Introduced CGI and Java Servlet support (the latter is currently
215 broken/unfinished).
216 * Introduced support for cookies.
217
218 Future Work
219 -----------
220
221 (Essential)
222
223 Twisted 1.3.0 does not provide file upload metadata, and Twisted Web 0.5.0
224 also seems to be missing this functionality. It isn't obvious whether Twisted
225 Web2 will just copy its predecessors and provide a similarly limited API.
226 Perhaps the Twisted support needs to resemble the CGI support much more when
227 handling fields.
228
229 JythonServlet libraries need to be configured using sys.add_package when
230 these do not feature in the compiled-in list. Adding such configuration to
231 the handler may be most appropriate (since the web.xml file can be too
232 arcane), but this needs testing.
233
234 (Important)
235
236 Field access needs testing, especially for anything using the
237 cgi.FieldStorage class, and the way file uploads are exposed should be
238 reviewed (currently the meta-data is not exposed). The acquisition of fields
239 from specific sources should be tested with different request methods - some
240 frameworks provide path fields in the body fields dictionary, others (eg.
241 Zope) change the fields exposed depending on request method.
242
243 Interpretation of path field encodings needs to be verified. Currently,
244 stray path fields are handled (eg. in WebStack.Helpers.Request) as being
245 ISO-8859-1, but it might be the case that some such fields might be
246 submitted as UTF-8. The decode_path method on Transaction does do much of the
247 work that is likely to be required, however. Still, a good policy for decoding
248 path fields, reducing the number of times one might specify the encoding in
249 various method calls, may be important.
250
251 An interesting test of encodings is to introduce things like the following to
252 the path info and query string sections of the URL: %25F0?%E6=%F8&%25F0=%F8
253 This should produce the following decoded result: %F0?æ=ø&%F0=ø
254 (The above needs to be read in ISO-8859-1 or ISO-8859-15.)
255
256 Cookie objects need defining strictly, especially since the standard library
257 Cookie object behaves differently to mod_python (and possibly Webware)
258 Cookie objects. Moreover, the set_cookie_value method needs to provide
259 access to the usual cookie parameters as supported by the frameworks. The
260 standard library Cookie module has issues with Unicode cookie names (and
261 possibly values) - this is worked around, but it would be best to resolve
262 this comprehensively.
263
264 UTF-16 (and possibly other encodings) causes problems with HTML form data
265 sent in POST requests using the application/x-www-form-urlencoded content
266 type. This should be reviewed at a later date when proper standardisation
267 has taken place.
268
269 Session support, especially through WebStack.Helpers.Session, should be
270 reviewed and be made compatible with non-cookie mechanisms.
271
272 Locking in the session support and in DirectoryRepository should be improved.
273
274 HeaderValue objects should be employed more extensively. Thus, the header
275 access methods may need to change their behaviour slightly. The get_headers
276 method should potentially return a list for each item in the dictionary.
277
278 WSGI support could demand that a special "end of headers" method be
279 introduced into WebStack, thus making response output more efficient (and
280 probably also for other frameworks, too).
281
282 The algorithm employed in the WebStack.Helpers.Auth.get_token function
283 should be reviewed and improved for better security.
284
285 Investigate proper support for HEAD, OPTIONS and other request methods.
286
287 Consider packages for different operating systems (other than Debian).
288
289 Provide some 500 error content when handle_errors is true.
290
291 (Completed/rejected)
292
293 The location of deployed applications in the filesystem should be exposed to
294 those applications. (This is actually available in the __file__ module
295 variable.)
296
297 Path information should be consistent across all frameworks, and the "path
298 info" value should be meaningful. (This should now be correct.)
299
300 Investigate the nicer functions in the cgi module, discarding the "magic"
301 stuff like FieldStorage. (These nicer functions are used by projects like
302 Twisted - as of 1.3.0 at least - and do not give the necessary information we
303 require.)
304
305 Release Procedures
306 ------------------
307
308 Update the WebStack/__init__.py __version__ attribute.
309 Change the version number and package filename/directory in the documentation.
310 Change code examples in the documentation if appropriate.
311 Update the release notes (see above).
312 Check the setup.py file and ensure that all package directories are mentioned.
313 Check the release information in the PKG-INFO file and in the package
314 changelog (and other files).
315 Tag, export.
316 Generate the PyServlet classes.
317 Generate the API documentation.
318 Remove generated .pyc files: rm `find . -name "*.pyc"`
319 Archive, upload.
320 Upload the introductory documentation.
321 Update PyPI, PythonInfo Wiki, Vaults of Parnassus entries.
322
323 Generating the API Documentation
324 --------------------------------
325
326 In order to prepare the API documentation, it is necessary to generate some
327 Web pages from the Python source code. For this, the epydoc application must
328 be available on your system. Then, inside the distribution directory, run the
329 apidocs.sh tool script as follows:
330
331 ./tools/apidocs.sh
332
333 Some warnings may be generated by the script, but the result should be a new
334 apidocs directory within the distribution directory.
335
336 Making Packages
337 ---------------
338
339 To make Debian-based packages:
340
341 1. Create new package directories under packages if necessary.
342 2. Make a symbolic link in the distribution's root directory to keep the
343 Debian tools happy:
344
345 ln -s packages/ubuntu-hoary/python2.4-webstack/debian/
346
347 3. Run the package builder:
348
349 dpkg-buildpackage -rfakeroot
350
351 4. Locate and tidy up the packages in the parent directory of the
352 distribution's root directory.