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 See the docs/supported-frameworks.html document for more information.
36
37 Dependencies
38 ------------
39
40 WebStack has the following basic dependencies:
41
42 Packages Release Information
43 -------- -------------------
44
45 libxml2dom 0.4.3 (for OpenID support)
46 libxml2 and libxslt Some combinations may not be reliable!
47 Tested with libxml2 2.6.17 and libxslt 1.1.12
48 Tested with libxml2 2.6.27 and libxslt 1.1.20
49 libxslt 1.1.17 should be avoided
50
51 If the OpenID support is not used, the above packages need not be installed.
52
53 New in WebStack 1.3 (Changes since WebStack 1.2.7)
54 --------------------------------------------------
55
56 * Changed the default_charset on WebStack.Generic.Transaction to UTF-8,
57 introducing a safe_default_charset attribute which employs ISO-8859-1, and
58 removing the default encoding on various resources, making them rely on
59 the default_charset property instead.
60 WARNING: These changes could upset some applications. The EncodingSelector
61 should be used to override the default_charset setting if appropriate.
62 * Added an encode_url_without_query to Transaction for use with combined
63 protocol, address and path values.
64 * Added a StringResource to WebStack.Resources.Static, serving strings as
65 responses.
66 * Added experimental OpenID support; improved the authentication resources
67 and mechanisms.
68 * Added a StoreSelector to WebStack.Resources.Selectors in order to provide
69 a convenient mechanism for database-related applications.
70
71 New in WebStack 1.2.7 (Changes since WebStack 1.2.6)
72 ----------------------------------------------------
73
74 * Fixed the MessageBodyStream class, adding an optional parameter to the
75 readline method which seems to be necessary when handling multipart
76 requests.
77 * Introduced stream usage for file uploads where possible, in order to
78 reduce memory usage (suggested by Kevin Glynn), adding a stream attribute
79 to the FileContent class and making the content attribute a property.
80 * Removed error handling in the examples in order to make troubleshooting
81 easier.
82 * Fixed header issues by introducing a special HeaderDict class which
83 enforces the case-insensitivity expected of header dictionaries.
84
85 New in WebStack 1.2.6 (Changes since WebStack 1.2.5)
86 ----------------------------------------------------
87
88 * Added a jython-webstack package for Ubuntu Feisty (7.04).
89 * Improved support for Jython on Ubuntu Feisty (7.04), adding python.path
90 and python.cachedir settings which respectively avoid issues with missing
91 libraries (due to the separation of libraries in the Ubuntu package) and
92 with failed imports (due to a read-only class cache directory).
93 * Improved the webstack_java_build.py script and added a deployment
94 descriptor for JSP to accompany the new Java Servlet-specific JSPTest
95 example.
96 * Added a special Java Servlet-specific get_servlet method to support the
97 JSPTest example. It is envisaged that a more general method could be made
98 available for all frameworks in order to support access to underlying
99 request dispatchers and other framework facilities.
100 * Added more Jython-related documentation as suggested by Kevin Glynn.
101 * Added missing request headers for CGI/WSGI environment variables.
102 * Fixed Webware support to work with Webware 0.9.4.
103 * Fixed/improved Zope path value retrieval.
104 * Added support for wsgiref, changing the WSGI deploy function for CGI-based
105 applications to deploy_as_cgi and adding a deploy_with_wsgiref function.
106
107 New in WebStack 1.2.5 (Changes since WebStack 1.2.4)
108 ----------------------------------------------------
109
110 * Fixed mod_python status codes using a solution proposed by John Krukoff.
111 * Fixed a Twisted deprecation warning when accessing port numbers, thanks to
112 John Krukoff.
113 * Added Ubuntu Feisty (7.04) package support.
114 * Tidied up the documentation HTML.
115
116 New in WebStack 1.2.4 (Changes since WebStack 1.2.3)
117 ----------------------------------------------------
118
119 * Made a SessionDirectoryRepository which uses directories for data produced
120 by the shelve module, rather than attempting to manipulate files produced
121 by the shelve module, since the details of such files may differ between
122 environments: a situation noticed by John Krukoff in an environment
123 without the bsddb module installed.
124
125 New in WebStack 1.2.3 (Changes since WebStack 1.2.2)
126 ----------------------------------------------------
127
128 * Fixed inadvertent OpenSSL dependency, noticed by John Krukoff.
129
130 New in WebStack 1.2.2 (Changes since WebStack 1.2.1)
131 ----------------------------------------------------
132
133 * Added an EncodingSelector class for the setting of default encodings on
134 transactions.
135 * Added some documentation about path processing strategies.
136 * Added a secure variant of the BaseHTTPServer provided in the adapter for
137 BaseHTTPRequestHandler.
138
139 New in WebStack 1.2.1 (Changes since WebStack 1.2)
140 --------------------------------------------------
141
142 * Fixed mod_python get_content_type method.
143 * Fixed LoginResource form field processing; changed the field type to
144 password.
145 * Exposed LoginResource and LoginRedirectResource page contents as
146 attributes.
147 * Added documentation about extending LoginRedirectResource and using
148 PathSelector to remember an application's root path.
149 * Changed handle_errors to 1 throughout the examples.
150
151 New in WebStack 1.2 (Changes since WebStack 1.1.2)
152 --------------------------------------------------
153
154 * Added support for Django.
155 * Fixed documentation about the representation of file upload fields.
156 * Changed mod_python, Java Servlet and Webware (> 0.8.1) deployment to use a
157 deploy function instead of more complicated configuration mechanisms.
158 * Improved mod_python deployment documentation and tools so that cleaner
159 application paths/URLs can now be used.
160 * Moved user and path_info default definitions into WebStack.Generic as
161 class attributes.
162 * Fixed encoding usage issues with path fields when using get_fields in a
163 Zope environment.
164 * Added a FileResource class to WebStack.Resources.Static.
165 * Made DirectoryRepository convert filenames to Unicode in all cases.
166 * Renamed the Apache and Java Servlet tools, making them scripts which are
167 installed by setup.py.
168 * Fixed CGI content charsets and languages support.
169 * Fixed CGI cookie output.
170 * Added URL overriding in the LoginRedirectResource.
171 * Exposed a get_target function from WebStack.Resources.Login in order to
172 better support alternative login resources.
173 * Added improved error reporting for BaseHTTPRequestHandler, CGI, Django and
174 WSGI.
175 * Added a traverse_path method to the Transaction class.
176 * Made a path_encoding alias for urlencoding in the initialisation of
177 WebStack.Resources.ResourceMap objects.
178 * Added a Selectors module to WebStack.Resources in order to support common
179 resource selection patterns.
180
181 New in WebStack 1.1.2 (Changes since WebStack 1.1.1)
182 ----------------------------------------------------
183
184 * Fixed missing import in WebStack.Repositories.Directory.
185
186 New in WebStack 1.1.1 (Changes since WebStack 1.1)
187 --------------------------------------------------
188
189 * Fixed update_path to handle the root path properly.
190
191 New in WebStack 1.1 (Changes since WebStack 1.0)
192 ------------------------------------------------
193
194 * Added a Repositories package to provide session-like support for
195 different kinds of storage.
196 * Added an explicit filesystem encoding to the Calendar example and adopted
197 the DirectoryRepository from the Repositories package.
198 * Added get_path_without_info, update_path and redirect methods to the
199 Transaction class.
200 * Added get_attributes (attribute support) to the Transaction class.
201 * Added a values method to Helpers.Session.Wrapper.
202 * Fixed get_processed_virtual_path_info (to match from right to left).
203 * Improved/fixed exception handling in the adapters so that transactions are
204 committed as the final act of an adapter experiencing an unhandled
205 exception. This should result in session stores being closed properly.
206 * Changed the Helpers.Session.SessionStore to use DirectoryRepository.
207 * Made the "not found" behaviour of DirectoryResource more configurable.
208 * Added documentation for MapResource and DirectoryResource.
209 * Fixed the distribution names in the Ubuntu changelog.
210
211 New in WebStack 1.0 (Changes since WebStack 0.10)
212 -------------------------------------------------
213
214 * Changed the behaviour of get_path, get_path_without_query, get_path_info,
215 get_virtual_path_info, get_processed_virtual_path_info and
216 get_fields_from_path to return Unicode data decoded using the optional
217 encoding parameter or a common default encoding.
218 * Fixed file upload values so that FileContent objects are returned for such
219 fields in get_fields_from_body and get_fields.
220 (Warning! Except for Twisted!)
221 * Fixed the JavaServlet support so that streams and file content are
222 obtained as "almost" plain strings.
223 * Updated/fixed LoginResource and LoginRedirectResource to use the updated
224 path API and to handle special characters properly.
225 * Added convenience methods to Transaction for the decoding and encoding of
226 path values (to and from Unicode objects) - see the decode_path and
227 encode_path methods.
228 * Added the notion of processed virtual path info - the part of the original
229 path info not represented in the current virtual path info.
230 * Added "pass through" behaviour to ResourceMap.MapResource (prompted by a
231 patch from Scott Robinson).
232 * Fixed ResourceMap.MapResource to handle non-existent resources properly
233 (where the virtual path info is only one component in length).
234 * Added Debian package support.
235 * Added automatic session directory creation for the WebStack sessions
236 implementation.
237 * Added support for the repeated retrieval of sessions from the same
238 WebStack session store, avoiding deadlocks.
239 * Fixed the calendar example, making it perform a proper function.
240 * Made the BaseHTTPRequestHandler and Twisted SimpleWithLogin applications
241 include the Login application, since Konqueror (at least) does not share
242 cookies across different port numbers on the same host.
243 * Added the SimpleWithLogin and Login applications to the demonstration.
244 * Improved the documentation, adding information on request headers, and
245 describing file upload and session support limitations.
246 * Improved the AOLserver-related notes for CGI and Webware, adding a patch
247 for Webware in order to work around AOLserver issues.
248
249 New in WebStack 0.10 (Changes since WebStack 0.9)
250 -------------------------------------------------
251
252 * Changes to make the tools/demo.py script work on Windows (and other)
253 platforms (suggested by Jim Madsen).
254 * Fixed end of header newlines for CGI (suggested by Matt Harrison).
255 * Minor documentation fixes and improvements, adding information on
256 AOLserver in the CGI and Webware notes.
257 * Changed the mod_python server name method to use the server object rather
258 than the connection object.
259 * Added a parameter to the ResourceMap.MapResource class to permit automatic
260 redirects into resource hierarchies when no trailing "/" was given in the
261 URL; changed the updated virtual path info so that empty values may be set
262 (the guarantee that "/" will always appear no longer applies).
263 * Fixed virtual path info retrieval when the value is an empty string.
264
265 New in WebStack 0.9 (Changes since WebStack 0.8)
266 ------------------------------------------------
267
268 * Standardised error handling in the adapters so that tracebacks can be
269 suppressed and an internal server error condition raised.
270 * Added overriding of path info in transactions.
271 * Added a ResourceMap resource for dispatching to different resources
272 according to path components.
273 * Standardised deployment for some frameworks (see docs/deploying.html).
274 * Introductory documentation in XHTML format.
275 * Added server name and port methods to the transaction.
276 * Added a simple demonstration application, incorporating many of the
277 examples and launched under a single script.
278 * Fixed mod_python native sessions.
279 * Fixed Zope request stream access.
280 * WebStack is now licensed under the LGPL - see docs/COPYING.txt for
281 details.
282
283 New in WebStack 0.8 (Changes since WebStack 0.7)
284 ------------------------------------------------
285
286 * Added a standard exception, EndOfResponse, which can be used to
287 immediately stop the processing/production of a response; this is useful
288 when resources need to issue a redirect without unnecessary content being
289 generated, for example.
290 * Fixed path information for Zope.
291 * Added WSGI support.
292 * Verified Twisted 1.3.0 support with Python 2.3.3.
293
294 New in WebStack 0.7 (Changes since WebStack 0.6)
295 ------------------------------------------------
296
297 * Fixed path information semantics.
298 * Fixed file upload semantics.
299 * Fixed content type handling for Unicode output and for interpreting
300 request body fields/parameters (although some improvement remains).
301 * Added a method to discover the chosen response stream encoding.
302 * Fixed field/parameter retrieval so that path and body fields are distinct,
303 regardless of the framework employed.
304 * Added a method to get a combination of path and body fields (suggested by
305 Jacob Smullyan).
306 * Introduced Zope 2 support.
307 * Improved Jython/Java Servlet API support (although a special PyServlet
308 class must now be used, and certain libraries must be deployed with
309 applications).
310 * Introduced authentication/authorisation support for Jython/Java Servlet
311 API.
312 * Session support has been added (except for Webware 0.8.1).
313 * Alternative cookie support for mod_python has been added.
314 * Cookie support now supports encoded Unicode sequences for names and
315 values.
316
317 New in WebStack 0.6 (Changes since WebStack 0.5)
318 ------------------------------------------------
319
320 * Introduced Jython/Java Servlet API support.
321 * Minor fixes to example applications and to BaseHTTPRequestHandler.
322
323 New in WebStack 0.5 (Changes since WebStack 0.4)
324 ------------------------------------------------
325
326 * Changed request body fields/parameters so that they are now represented
327 using Unicode objects rather than plain strings.
328 * Introduced better support for Unicode in response streams.
329
330 New in WebStack 0.4 (Changes since WebStack 0.3)
331 ------------------------------------------------
332
333 * Added application definition of user identity, permitting alternative
334 authentication mechanisms.
335 * Improved BaseHTTPRequestHandler and mod_python reliability around fields
336 from request bodies.
337 * Provided stream and environment parameterisation in the CGI adapter.
338 * Added LoginRedirect and Login examples.
339 * Added get_path_without_query and fixed get_path behaviour.
340
341 New in WebStack 0.3 (Changes since WebStack 0.2)
342 ------------------------------------------------
343
344 * Added better header support for Webware (suggested by Ian Bicking).
345 * Introduced CGI and Java Servlet support (the latter is currently
346 broken/unfinished).
347 * Introduced support for cookies.
348
349 Future Work
350 -----------
351
352 (Essential)
353
354 Twisted 1.3.0 does not provide file upload metadata, and Twisted Web 0.5.0
355 also seems to be missing this functionality. It isn't obvious whether Twisted
356 Web2 will just copy its predecessors and provide a similarly limited API.
357 Perhaps the Twisted support needs to resemble the CGI support much more when
358 handling fields.
359
360 JythonServlet libraries need to be configured using sys.add_package when
361 these do not feature in the compiled-in list. Adding such configuration to
362 the handler may be most appropriate (since the web.xml file can be too
363 arcane), but this needs testing.
364
365 The algorithm employed in the WebStack.Helpers.Auth.get_token function
366 should be reviewed and improved for better security.
367
368 (Important)
369
370 Field access needs testing, especially for anything using the
371 cgi.FieldStorage class, and the way file uploads are exposed should be
372 reviewed (currently the meta-data is not exposed). The acquisition of fields
373 from specific sources should be tested with different request methods - some
374 frameworks provide path fields in the body fields dictionary, others (eg.
375 Zope) change the fields exposed depending on request method.
376
377 Interpretation of path field encodings needs to be verified. Currently,
378 stray path fields are handled (eg. in WebStack.Helpers.Request) as being
379 ISO-8859-1, but it might be the case that some such fields might be
380 submitted as UTF-8. The decode_path method on Transaction does do much of the
381 work that is likely to be required, however. Still, a good policy for decoding
382 path fields, reducing the number of times one might specify the encoding in
383 various method calls, may be important.
384
385 An interesting test of encodings is to introduce things like the following to
386 the path info and query string sections of the URL: %25F0?%E6=%F8&%25F0=%F8
387 This should produce the following decoded result: %F0?æ=ø&%F0=ø
388 (The above needs to be read in ISO-8859-1 or ISO-8859-15.)
389
390 Cookie objects need defining strictly, especially since the standard library
391 Cookie object behaves differently to mod_python (and possibly Webware)
392 Cookie objects. Moreover, the set_cookie_value method needs to provide
393 access to the usual cookie parameters as supported by the frameworks. The
394 standard library Cookie module has issues with Unicode cookie names (and
395 possibly values) - this is worked around, but it would be best to resolve
396 this comprehensively.
397
398 UTF-16 (and possibly other encodings) causes problems with HTML form data
399 sent in POST requests using the application/x-www-form-urlencoded content
400 type. This should be reviewed at a later date when proper standardisation
401 has taken place.
402
403 Session support, especially through WebStack.Helpers.Session, should be
404 reviewed and be made compatible with non-cookie mechanisms.
405
406 Locking in the session support and in DirectoryRepository should be improved.
407
408 HeaderValue objects should be employed more extensively. Thus, the header
409 access methods may need to change their behaviour slightly. The get_headers
410 method should potentially return a list for each item in the dictionary.
411
412 WSGI support could demand that a special "end of headers" method be
413 introduced into WebStack, thus making response output more efficient (and
414 probably also for other frameworks, too).
415
416 Investigate proper support for HEAD, OPTIONS and other request methods.
417
418 Consider packages for different operating systems (other than Debian).
419
420 Investigate cStringIO usage.
421
422 The location of deployed applications in the filesystem should be exposed to
423 those applications. (This is actually available in the __file__ module
424 variable.) A resource could be provided to record the "root" path and added to
425 a resource hierarchy or site map. Note that PathSelector records the "root"
426 path, although it is not automatically deployed.
427
428 (Completed/rejected)
429
430 Path information should be consistent across all frameworks, and the "path
431 info" value should be meaningful. (This should now be correct.)
432
433 Investigate the nicer functions in the cgi module, discarding the "magic"
434 stuff like FieldStorage. (These nicer functions are used by projects like
435 Twisted - as of 1.3.0 at least - and do not give the necessary information we
436 require.)
437
438 Release Procedures
439 ------------------
440
441 Update the WebStack/__init__.py __version__ attribute.
442 Change the version number and package filename/directory in the documentation.
443 Change code examples in the documentation if appropriate.
444 Update the release notes (see above).
445 Check the setup.py file and ensure that all package directories are mentioned.
446 Check the release information in the PKG-INFO file and in the package
447 changelog (and other files).
448 Tag, export.
449 Generate the PyServlet classes.
450 Generate the API documentation.
451 Remove generated .pyc files: rm `find . -name "*.pyc"`
452 Archive, upload.
453 Upload the introductory documentation.
454 Update PyPI, PythonInfo Wiki entries.
455
456 Generating the PyServlet Classes
457 --------------------------------
458
459 In order to generate the PyServlet classes, it is necessary to run the
460 supplied script:
461
462 ./tools/JavaServlet/compile.sh
463
464 This produces Java classes and a .jar file for use by WebStack applications
465 running on the Java platform.
466
467 Generating the API Documentation
468 --------------------------------
469
470 In order to prepare the API documentation, it is necessary to generate some
471 Web pages from the Python source code. For this, the epydoc application must
472 be available on your system. Then, inside the distribution directory, run the
473 apidocs.sh tool script as follows:
474
475 ./tools/apidocs.sh
476
477 Some warnings may be generated by the script, but the result should be a new
478 apidocs directory within the distribution directory.
479
480 Making Packages
481 ---------------
482
483 To make Debian-based packages:
484
485 1. Create new package directories under packages if necessary.
486 2. Make a symbolic link in the distribution's root directory to keep the
487 Debian tools happy. For example, one of the following:
488
489 ln -s packages/ubuntu-hoary/python2.4-webstack/debian/
490 ln -s packages/ubuntu-feisty/python-webstack/debian/
491 ln -s packages/ubuntu-feisty/jython-webstack/debian/
492
493 3. Run the package builder:
494
495 dpkg-buildpackage -rfakeroot
496
497 4. Locate and tidy up the packages in the parent directory of the
498 distribution's root directory.