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