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