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