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