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