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