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