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 1.0.1 (Changes since WebStack 1.0)
56 --------------------------------------------------
57
58 * Added an explicit filesystem encoding to the Calendar example.
59 * Fixed the distribution names in the Ubuntu changelog.
60
61 New in WebStack 1.0 (Changes since WebStack 0.10)
62 -------------------------------------------------
63
64 * Changed the behaviour of get_path, get_path_without_query, get_path_info,
65 get_virtual_path_info, get_processed_virtual_path_info and
66 get_fields_from_path to return Unicode data decoded using the optional
67 encoding parameter or a common default encoding.
68 * Fixed file upload values so that FileContent objects are returned for such
69 fields in get_fields_from_body and get_fields.
70 (Warning! Except for Twisted!)
71 * Fixed the JavaServlet support so that streams and file content are
72 obtained as "almost" plain strings.
73 * Updated/fixed LoginResource and LoginRedirectResource to use the updated
74 path API and to handle special characters properly.
75 * Added convenience methods to Transaction for the decoding and encoding of
76 path values (to and from Unicode objects) - see the decode_path and
77 encode_path methods.
78 * Added the notion of processed virtual path info - the part of the original
79 path info not represented in the current virtual path info.
80 * Added "pass through" behaviour to ResourceMap.MapResource (prompted by a
81 patch from Scott Robinson).
82 * Fixed ResourceMap.MapResource to handle non-existent resources properly
83 (where the virtual path info is only one component in length).
84 * Added Debian package support.
85 * Added automatic session directory creation for the WebStack sessions
86 implementation.
87 * Added support for the repeated retrieval of sessions from the same
88 WebStack session store, avoiding deadlocks.
89 * Fixed the calendar example, making it perform a proper function.
90 * Made the BaseHTTPRequestHandler and Twisted SimpleWithLogin applications
91 include the Login application, since Konqueror (at least) does not share
92 cookies across different port numbers on the same host.
93 * Added the SimpleWithLogin and Login applications to the demonstration.
94 * Improved the documentation, adding information on request headers, and
95 describing file upload and session support limitations.
96 * Improved the AOLserver-related notes for CGI and Webware, adding a patch
97 for Webware in order to work around AOLserver issues.
98
99 New in WebStack 0.10 (Changes since WebStack 0.9)
100 -------------------------------------------------
101
102 * Changes to make the tools/demo.py script work on Windows (and other)
103 platforms (suggested by Jim Madsen).
104 * Fixed end of header newlines for CGI (suggested by Matt Harrison).
105 * Minor documentation fixes and improvements, adding information on
106 AOLserver in the CGI and Webware notes.
107 * Changed the mod_python server name method to use the server object rather
108 than the connection object.
109 * Added a parameter to the ResourceMap.MapResource class to permit automatic
110 redirects into resource hierarchies when no trailing "/" was given in the
111 URL; changed the updated virtual path info so that empty values may be set
112 (the guarantee that "/" will always appear no longer applies).
113 * Fixed virtual path info retrieval when the value is an empty string.
114
115 New in WebStack 0.9 (Changes since WebStack 0.8)
116 ------------------------------------------------
117
118 * Standardised error handling in the adapters so that tracebacks can be
119 suppressed and an internal server error condition raised.
120 * Added overriding of path info in transactions.
121 * Added a ResourceMap resource for dispatching to different resources
122 according to path components.
123 * Standardised deployment for some frameworks (see docs/deploying.html).
124 * Introductory documentation in XHTML format.
125 * Added server name and port methods to the transaction.
126 * Added a simple demonstration application, incorporating many of the
127 examples and launched under a single script.
128 * Fixed mod_python native sessions.
129 * Fixed Zope request stream access.
130 * WebStack is now licensed under the LGPL - see docs/COPYING.txt for
131 details.
132
133 New in WebStack 0.8 (Changes since WebStack 0.7)
134 ------------------------------------------------
135
136 * Added a standard exception, EndOfResponse, which can be used to
137 immediately stop the processing/production of a response; this is useful
138 when resources need to issue a redirect without unnecessary content being
139 generated, for example.
140 * Fixed path information for Zope.
141 * Added WSGI support.
142 * Verified Twisted 1.3.0 support with Python 2.3.3.
143
144 New in WebStack 0.7 (Changes since WebStack 0.6)
145 ------------------------------------------------
146
147 * Fixed path information semantics.
148 * Fixed file upload semantics.
149 * Fixed content type handling for Unicode output and for interpreting
150 request body fields/parameters (although some improvement remains).
151 * Added a method to discover the chosen response stream encoding.
152 * Fixed field/parameter retrieval so that path and body fields are distinct,
153 regardless of the framework employed.
154 * Added a method to get a combination of path and body fields (suggested by
155 Jacob Smullyan).
156 * Introduced Zope 2 support.
157 * Improved Jython/Java Servlet API support (although a special PyServlet
158 class must now be used, and certain libraries must be deployed with
159 applications).
160 * Introduced authentication/authorisation support for Jython/Java Servlet
161 API.
162 * Session support has been added (except for Webware 0.8.1).
163 * Alternative cookie support for mod_python has been added.
164 * Cookie support now supports encoded Unicode sequences for names and
165 values.
166
167 New in WebStack 0.6 (Changes since WebStack 0.5)
168 ------------------------------------------------
169
170 * Introduced Jython/Java Servlet API support.
171 * Minor fixes to example applications and to BaseHTTPRequestHandler.
172
173 New in WebStack 0.5 (Changes since WebStack 0.4)
174 ------------------------------------------------
175
176 * Changed request body fields/parameters so that they are now represented
177 using Unicode objects rather than plain strings.
178 * Introduced better support for Unicode in response streams.
179
180 New in WebStack 0.4 (Changes since WebStack 0.3)
181 ------------------------------------------------
182
183 * Added application definition of user identity, permitting alternative
184 authentication mechanisms.
185 * Improved BaseHTTPRequestHandler and mod_python reliability around fields
186 from request bodies.
187 * Provided stream and environment parameterisation in the CGI adapter.
188 * Added LoginRedirect and Login examples.
189 * Added get_path_without_query and fixed get_path behaviour.
190
191 New in WebStack 0.3 (Changes since WebStack 0.2)
192 ------------------------------------------------
193
194 * Added better header support for Webware (suggested by Ian Bicking).
195 * Introduced CGI and Java Servlet support (the latter is currently
196 broken/unfinished).
197 * Introduced support for cookies.
198
199 Future Work
200 -----------
201
202 (Essential)
203
204 Twisted 1.3.0 does not provide file upload metadata, and Twisted Web 0.5.0
205 also seems to be missing this functionality. It isn't obvious whether Twisted
206 Web2 will just copy its predecessors and provide a similarly limited API.
207 Perhaps the Twisted support needs to resemble the CGI support much more when
208 handling fields.
209
210 JythonServlet libraries need to be configured using sys.add_package when
211 these do not feature in the compiled-in list. Adding such configuration to
212 the handler may be most appropriate (since the web.xml file can be too
213 arcane), but this needs testing.
214
215 (Important)
216
217 Things to consider for future releases: improved cookie support, redirects,
218 access to shared resources and much better documentation.
219
220 Field access needs testing, especially for anything using the
221 cgi.FieldStorage class, and the way file uploads are exposed should be
222 reviewed (currently the meta-data is not exposed). The acquisition of fields
223 from specific sources should be tested with different request methods - some
224 frameworks provide path fields in the body fields dictionary, others (eg.
225 Zope) change the fields exposed depending on request method.
226
227 Interpretation of path field encodings needs to be verified. Currently,
228 stray path fields are handled (eg. in WebStack.Helpers.Request) as being
229 ISO-8859-1, but it might be the case that some such fields might be
230 submitted as UTF-8. The decode_path method on Transaction does do much of the
231 work that is likely to be required, however. Still, a good policy for decoding
232 path fields, reducing the number of times one might specify the encoding in
233 various method calls, may be important.
234
235 An interesting test of encodings is to introduce things like the following to
236 the path info and query string sections of the URL: %25F0?%E6=%F8&%25F0=%F8
237 This should produce the following decoded result: %F0?æ=ø&%F0=ø
238 (The above needs to be read in ISO-8859-1 or ISO-8859-15.)
239
240 Cookie objects need defining strictly, especially since the standard library
241 Cookie object behaves differently to mod_python (and possibly Webware)
242 Cookie objects. Moreover, the set_cookie_value method needs to provide
243 access to the usual cookie parameters as supported by the frameworks. The
244 standard library Cookie module has issues with Unicode cookie names (and
245 possibly values) - this is worked around, but it would be best to resolve
246 this comprehensively.
247
248 UTF-16 (and possibly other encodings) causes problems with HTML form data
249 sent in POST requests using the application/x-www-form-urlencoded content
250 type. This should be reviewed at a later date when proper standardisation
251 has taken place.
252
253 Session support, especially through WebStack.Helpers.Session, should be
254 reviewed and be made compatible with non-cookie mechanisms.
255
256 HeaderValue objects should be employed more extensively. Thus, the header
257 access methods may need to change their behaviour slightly. The get_headers
258 method should potentially return a list for each item in the dictionary.
259
260 WSGI support could demand that a special "end of headers" method be
261 introduced into WebStack, thus making response output more efficient (and
262 probably also for other frameworks, too).
263
264 The algorithm employed in the WebStack.Helpers.Auth.get_token function
265 should be reviewed and improved for better security.
266
267 Investigate proper support for HEAD, OPTIONS and other request methods.
268
269 Consider packages for different operating systems (other than Debian).
270
271 Provide some 500 error content when handle_errors is true.
272
273 (Completed/rejected)
274
275 The location of deployed applications in the filesystem should be exposed to
276 those applications. (This is actually available in the __file__ module
277 variable.)
278
279 Path information should be consistent across all frameworks, and the "path
280 info" value should be meaningful. (This should now be correct.)
281
282 Investigate the nicer functions in the cgi module, discarding the "magic"
283 stuff like FieldStorage. (These nicer functions are used by projects like
284 Twisted - as of 1.3.0 at least - and do not give the necessary information we
285 require.)
286
287 Release Procedures
288 ------------------
289
290 Update the WebStack/__init__.py __version__ attribute.
291 Change the version number and package filename/directory in the documentation.
292 Change code examples in the documentation if appropriate.
293 Update the release notes (see above).
294 Check the setup.py file and ensure that all package directories are mentioned.
295 Check the release information in the PKG-INFO file and in the package
296 changelog (and other files).
297 Tag, export.
298 Generate the PyServlet classes.
299 Generate the API documentation.
300 Remove generated .pyc files: rm `find . -name "*.pyc"`
301 Archive, upload.
302 Upload the introductory documentation.
303 Update PyPI, PythonInfo Wiki, Vaults of Parnassus entries.
304
305 Generating the API Documentation
306 --------------------------------
307
308 In order to prepare the API documentation, it is necessary to generate some
309 Web pages from the Python source code. For this, the epydoc application must
310 be available on your system. Then, inside the distribution directory, run the
311 apidocs.sh tool script as follows:
312
313 ./tools/apidocs.sh
314
315 Some warnings may be generated by the script, but the result should be a new
316 apidocs directory within the distribution directory.
317
318 Making Packages
319 ---------------
320
321 To make Debian-based packages:
322
323 1. Create new package directories under packages if necessary.
324 2. Make a symbolic link in the distribution's root directory to keep the
325 Debian tools happy:
326
327 ln -s packages/ubuntu-hoary/python2.4-webstack/debian/
328
329 3. Run the package builder:
330
331 dpkg-buildpackage -rfakeroot
332
333 4. Locate and tidy up the packages in the parent directory of the
334 distribution's root directory.