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 Last-Modified headers to DirectoryResource and FileResource
67 responses.
68 * Added experimental OpenID support; improved the authentication resources
69 and mechanisms.
70 * Added a StoreSelector to WebStack.Resources.Selectors in order to provide
71 a convenient mechanism for database-related applications.
72 * Changed LoginRedirectResource to use class attributes for various optional
73 parameters, rather than having these supplied to the initialiser.
74 WARNING: These changes could affect some applications.
75 * Added a SiteLoginRedirectResource for site-specific login redirection to
76 WebStack.Resources.LoginRedirect.
77 * Added AuthInfoSelector for the retrieval of authentication details and
78 ConditionalAuthSelector for conditional authentication to
79 WebStack.Resources.Selectors.
80 * Added a filename attribute to FileContent instances, provided for file
81 upload parameters.
82
83 New in WebStack 1.2.7 (Changes since WebStack 1.2.6)
84 ----------------------------------------------------
85
86 * Fixed the MessageBodyStream class, adding an optional parameter to the
87 readline method which seems to be necessary when handling multipart
88 requests.
89 * Introduced stream usage for file uploads where possible, in order to
90 reduce memory usage (suggested by Kevin Glynn), adding a stream attribute
91 to the FileContent class and making the content attribute a property.
92 * Removed error handling in the examples in order to make troubleshooting
93 easier.
94 * Fixed header issues by introducing a special HeaderDict class which
95 enforces the case-insensitivity expected of header dictionaries.
96
97 New in WebStack 1.2.6 (Changes since WebStack 1.2.5)
98 ----------------------------------------------------
99
100 * Added a jython-webstack package for Ubuntu Feisty (7.04).
101 * Improved support for Jython on Ubuntu Feisty (7.04), adding python.path
102 and python.cachedir settings which respectively avoid issues with missing
103 libraries (due to the separation of libraries in the Ubuntu package) and
104 with failed imports (due to a read-only class cache directory).
105 * Improved the webstack_java_build.py script and added a deployment
106 descriptor for JSP to accompany the new Java Servlet-specific JSPTest
107 example.
108 * Added a special Java Servlet-specific get_servlet method to support the
109 JSPTest example. It is envisaged that a more general method could be made
110 available for all frameworks in order to support access to underlying
111 request dispatchers and other framework facilities.
112 * Added more Jython-related documentation as suggested by Kevin Glynn.
113 * Added missing request headers for CGI/WSGI environment variables.
114 * Fixed Webware support to work with Webware 0.9.4.
115 * Fixed/improved Zope path value retrieval.
116 * Added support for wsgiref, changing the WSGI deploy function for CGI-based
117 applications to deploy_as_cgi and adding a deploy_with_wsgiref function.
118
119 New in WebStack 1.2.5 (Changes since WebStack 1.2.4)
120 ----------------------------------------------------
121
122 * Fixed mod_python status codes using a solution proposed by John Krukoff.
123 * Fixed a Twisted deprecation warning when accessing port numbers, thanks to
124 John Krukoff.
125 * Added Ubuntu Feisty (7.04) package support.
126 * Tidied up the documentation HTML.
127
128 New in WebStack 1.2.4 (Changes since WebStack 1.2.3)
129 ----------------------------------------------------
130
131 * Made a SessionDirectoryRepository which uses directories for data produced
132 by the shelve module, rather than attempting to manipulate files produced
133 by the shelve module, since the details of such files may differ between
134 environments: a situation noticed by John Krukoff in an environment
135 without the bsddb module installed.
136
137 New in WebStack 1.2.3 (Changes since WebStack 1.2.2)
138 ----------------------------------------------------
139
140 * Fixed inadvertent OpenSSL dependency, noticed by John Krukoff.
141
142 New in WebStack 1.2.2 (Changes since WebStack 1.2.1)
143 ----------------------------------------------------
144
145 * Added an EncodingSelector class for the setting of default encodings on
146 transactions.
147 * Added some documentation about path processing strategies.
148 * Added a secure variant of the BaseHTTPServer provided in the adapter for
149 BaseHTTPRequestHandler.
150
151 New in WebStack 1.2.1 (Changes since WebStack 1.2)
152 --------------------------------------------------
153
154 * Fixed mod_python get_content_type method.
155 * Fixed LoginResource form field processing; changed the field type to
156 password.
157 * Exposed LoginResource and LoginRedirectResource page contents as
158 attributes.
159 * Added documentation about extending LoginRedirectResource and using
160 PathSelector to remember an application's root path.
161 * Changed handle_errors to 1 throughout the examples.
162
163 New in WebStack 1.2 (Changes since WebStack 1.1.2)
164 --------------------------------------------------
165
166 * Added support for Django.
167 * Fixed documentation about the representation of file upload fields.
168 * Changed mod_python, Java Servlet and Webware (> 0.8.1) deployment to use a
169 deploy function instead of more complicated configuration mechanisms.
170 * Improved mod_python deployment documentation and tools so that cleaner
171 application paths/URLs can now be used.
172 * Moved user and path_info default definitions into WebStack.Generic as
173 class attributes.
174 * Fixed encoding usage issues with path fields when using get_fields in a
175 Zope environment.
176 * Added a FileResource class to WebStack.Resources.Static.
177 * Made DirectoryRepository convert filenames to Unicode in all cases.
178 * Renamed the Apache and Java Servlet tools, making them scripts which are
179 installed by setup.py.
180 * Fixed CGI content charsets and languages support.
181 * Fixed CGI cookie output.
182 * Added URL overriding in the LoginRedirectResource.
183 * Exposed a get_target function from WebStack.Resources.Login in order to
184 better support alternative login resources.
185 * Added improved error reporting for BaseHTTPRequestHandler, CGI, Django and
186 WSGI.
187 * Added a traverse_path method to the Transaction class.
188 * Made a path_encoding alias for urlencoding in the initialisation of
189 WebStack.Resources.ResourceMap objects.
190 * Added a Selectors module to WebStack.Resources in order to support common
191 resource selection patterns.
192
193 New in WebStack 1.1.2 (Changes since WebStack 1.1.1)
194 ----------------------------------------------------
195
196 * Fixed missing import in WebStack.Repositories.Directory.
197
198 New in WebStack 1.1.1 (Changes since WebStack 1.1)
199 --------------------------------------------------
200
201 * Fixed update_path to handle the root path properly.
202
203 New in WebStack 1.1 (Changes since WebStack 1.0)
204 ------------------------------------------------
205
206 * Added a Repositories package to provide session-like support for
207 different kinds of storage.
208 * Added an explicit filesystem encoding to the Calendar example and adopted
209 the DirectoryRepository from the Repositories package.
210 * Added get_path_without_info, update_path and redirect methods to the
211 Transaction class.
212 * Added get_attributes (attribute support) to the Transaction class.
213 * Added a values method to Helpers.Session.Wrapper.
214 * Fixed get_processed_virtual_path_info (to match from right to left).
215 * Improved/fixed exception handling in the adapters so that transactions are
216 committed as the final act of an adapter experiencing an unhandled
217 exception. This should result in session stores being closed properly.
218 * Changed the Helpers.Session.SessionStore to use DirectoryRepository.
219 * Made the "not found" behaviour of DirectoryResource more configurable.
220 * Added documentation for MapResource and DirectoryResource.
221 * Fixed the distribution names in the Ubuntu changelog.
222
223 New in WebStack 1.0 (Changes since WebStack 0.10)
224 -------------------------------------------------
225
226 * Changed the behaviour of get_path, get_path_without_query, get_path_info,
227 get_virtual_path_info, get_processed_virtual_path_info and
228 get_fields_from_path to return Unicode data decoded using the optional
229 encoding parameter or a common default encoding.
230 * Fixed file upload values so that FileContent objects are returned for such
231 fields in get_fields_from_body and get_fields.
232 (Warning! Except for Twisted!)
233 * Fixed the JavaServlet support so that streams and file content are
234 obtained as "almost" plain strings.
235 * Updated/fixed LoginResource and LoginRedirectResource to use the updated
236 path API and to handle special characters properly.
237 * Added convenience methods to Transaction for the decoding and encoding of
238 path values (to and from Unicode objects) - see the decode_path and
239 encode_path methods.
240 * Added the notion of processed virtual path info - the part of the original
241 path info not represented in the current virtual path info.
242 * Added "pass through" behaviour to ResourceMap.MapResource (prompted by a
243 patch from Scott Robinson).
244 * Fixed ResourceMap.MapResource to handle non-existent resources properly
245 (where the virtual path info is only one component in length).
246 * Added Debian package support.
247 * Added automatic session directory creation for the WebStack sessions
248 implementation.
249 * Added support for the repeated retrieval of sessions from the same
250 WebStack session store, avoiding deadlocks.
251 * Fixed the calendar example, making it perform a proper function.
252 * Made the BaseHTTPRequestHandler and Twisted SimpleWithLogin applications
253 include the Login application, since Konqueror (at least) does not share
254 cookies across different port numbers on the same host.
255 * Added the SimpleWithLogin and Login applications to the demonstration.
256 * Improved the documentation, adding information on request headers, and
257 describing file upload and session support limitations.
258 * Improved the AOLserver-related notes for CGI and Webware, adding a patch
259 for Webware in order to work around AOLserver issues.
260
261 New in WebStack 0.10 (Changes since WebStack 0.9)
262 -------------------------------------------------
263
264 * Changes to make the tools/demo.py script work on Windows (and other)
265 platforms (suggested by Jim Madsen).
266 * Fixed end of header newlines for CGI (suggested by Matt Harrison).
267 * Minor documentation fixes and improvements, adding information on
268 AOLserver in the CGI and Webware notes.
269 * Changed the mod_python server name method to use the server object rather
270 than the connection object.
271 * Added a parameter to the ResourceMap.MapResource class to permit automatic
272 redirects into resource hierarchies when no trailing "/" was given in the
273 URL; changed the updated virtual path info so that empty values may be set
274 (the guarantee that "/" will always appear no longer applies).
275 * Fixed virtual path info retrieval when the value is an empty string.
276
277 New in WebStack 0.9 (Changes since WebStack 0.8)
278 ------------------------------------------------
279
280 * Standardised error handling in the adapters so that tracebacks can be
281 suppressed and an internal server error condition raised.
282 * Added overriding of path info in transactions.
283 * Added a ResourceMap resource for dispatching to different resources
284 according to path components.
285 * Standardised deployment for some frameworks (see docs/deploying.html).
286 * Introductory documentation in XHTML format.
287 * Added server name and port methods to the transaction.
288 * Added a simple demonstration application, incorporating many of the
289 examples and launched under a single script.
290 * Fixed mod_python native sessions.
291 * Fixed Zope request stream access.
292 * WebStack is now licensed under the LGPL - see docs/COPYING.txt for
293 details.
294
295 New in WebStack 0.8 (Changes since WebStack 0.7)
296 ------------------------------------------------
297
298 * Added a standard exception, EndOfResponse, which can be used to
299 immediately stop the processing/production of a response; this is useful
300 when resources need to issue a redirect without unnecessary content being
301 generated, for example.
302 * Fixed path information for Zope.
303 * Added WSGI support.
304 * Verified Twisted 1.3.0 support with Python 2.3.3.
305
306 New in WebStack 0.7 (Changes since WebStack 0.6)
307 ------------------------------------------------
308
309 * Fixed path information semantics.
310 * Fixed file upload semantics.
311 * Fixed content type handling for Unicode output and for interpreting
312 request body fields/parameters (although some improvement remains).
313 * Added a method to discover the chosen response stream encoding.
314 * Fixed field/parameter retrieval so that path and body fields are distinct,
315 regardless of the framework employed.
316 * Added a method to get a combination of path and body fields (suggested by
317 Jacob Smullyan).
318 * Introduced Zope 2 support.
319 * Improved Jython/Java Servlet API support (although a special PyServlet
320 class must now be used, and certain libraries must be deployed with
321 applications).
322 * Introduced authentication/authorisation support for Jython/Java Servlet
323 API.
324 * Session support has been added (except for Webware 0.8.1).
325 * Alternative cookie support for mod_python has been added.
326 * Cookie support now supports encoded Unicode sequences for names and
327 values.
328
329 New in WebStack 0.6 (Changes since WebStack 0.5)
330 ------------------------------------------------
331
332 * Introduced Jython/Java Servlet API support.
333 * Minor fixes to example applications and to BaseHTTPRequestHandler.
334
335 New in WebStack 0.5 (Changes since WebStack 0.4)
336 ------------------------------------------------
337
338 * Changed request body fields/parameters so that they are now represented
339 using Unicode objects rather than plain strings.
340 * Introduced better support for Unicode in response streams.
341
342 New in WebStack 0.4 (Changes since WebStack 0.3)
343 ------------------------------------------------
344
345 * Added application definition of user identity, permitting alternative
346 authentication mechanisms.
347 * Improved BaseHTTPRequestHandler and mod_python reliability around fields
348 from request bodies.
349 * Provided stream and environment parameterisation in the CGI adapter.
350 * Added LoginRedirect and Login examples.
351 * Added get_path_without_query and fixed get_path behaviour.
352
353 New in WebStack 0.3 (Changes since WebStack 0.2)
354 ------------------------------------------------
355
356 * Added better header support for Webware (suggested by Ian Bicking).
357 * Introduced CGI and Java Servlet support (the latter is currently
358 broken/unfinished).
359 * Introduced support for cookies.
360
361 Future Work
362 -----------
363
364 (Essential)
365
366 Twisted 1.3.0 does not provide file upload metadata, and Twisted Web 0.5.0
367 also seems to be missing this functionality. It isn't obvious whether Twisted
368 Web2 will just copy its predecessors and provide a similarly limited API.
369 Perhaps the Twisted support needs to resemble the CGI support much more when
370 handling fields.
371
372 JythonServlet libraries need to be configured using sys.add_package when
373 these do not feature in the compiled-in list. Adding such configuration to
374 the handler may be most appropriate (since the web.xml file can be too
375 arcane), but this needs testing.
376
377 The algorithm employed in the WebStack.Helpers.Auth.get_token function
378 should be reviewed and improved for better security.
379
380 (Important)
381
382 Field access needs testing, especially for anything using the
383 cgi.FieldStorage class, and the way file uploads are exposed should be
384 reviewed (currently the meta-data is not exposed). The acquisition of fields
385 from specific sources should be tested with different request methods - some
386 frameworks provide path fields in the body fields dictionary, others (eg.
387 Zope) change the fields exposed depending on request method.
388
389 Interpretation of path field encodings needs to be verified. Currently,
390 stray path fields are handled (eg. in WebStack.Helpers.Request) as being
391 ISO-8859-1, but it might be the case that some such fields might be
392 submitted as UTF-8. The decode_path method on Transaction does do much of the
393 work that is likely to be required, however. Still, a good policy for decoding
394 path fields, reducing the number of times one might specify the encoding in
395 various method calls, may be important.
396
397 An interesting test of encodings is to introduce things like the following to
398 the path info and query string sections of the URL: %25F0?%E6=%F8&%25F0=%F8
399 This should produce the following decoded result: %F0?æ=ø&%F0=ø
400 (The above needs to be read in ISO-8859-1 or ISO-8859-15.)
401
402 Cookie objects need defining strictly, especially since the standard library
403 Cookie object behaves differently to mod_python (and possibly Webware)
404 Cookie objects. Moreover, the set_cookie_value method needs to provide
405 access to the usual cookie parameters as supported by the frameworks. The
406 standard library Cookie module has issues with Unicode cookie names (and
407 possibly values) - this is worked around, but it would be best to resolve
408 this comprehensively.
409
410 UTF-16 (and possibly other encodings) causes problems with HTML form data
411 sent in POST requests using the application/x-www-form-urlencoded content
412 type. This should be reviewed at a later date when proper standardisation
413 has taken place.
414
415 Session support, especially through WebStack.Helpers.Session, should be
416 reviewed and be made compatible with non-cookie mechanisms.
417
418 Locking in the session support and in DirectoryRepository should be improved.
419
420 HeaderValue objects should be employed more extensively. Thus, the header
421 access methods may need to change their behaviour slightly. The get_headers
422 method should potentially return a list for each item in the dictionary.
423
424 WSGI support could demand that a special "end of headers" method be
425 introduced into WebStack, thus making response output more efficient (and
426 probably also for other frameworks, too).
427
428 Investigate proper support for HEAD, OPTIONS and other request methods.
429
430 Consider packages for different operating systems (other than Debian).
431
432 Investigate cStringIO usage.
433
434 The location of deployed applications in the filesystem should be exposed to
435 those applications. (This is actually available in the __file__ module
436 variable.) A resource could be provided to record the "root" path and added to
437 a resource hierarchy or site map. Note that PathSelector records the "root"
438 path, although it is not automatically deployed.
439
440 (Completed/rejected)
441
442 Path information should be consistent across all frameworks, and the "path
443 info" value should be meaningful. (This should now be correct.)
444
445 Investigate the nicer functions in the cgi module, discarding the "magic"
446 stuff like FieldStorage. (These nicer functions are used by projects like
447 Twisted - as of 1.3.0 at least - and do not give the necessary information we
448 require.)
449
450 Release Procedures
451 ------------------
452
453 Update the WebStack/__init__.py __version__ attribute.
454 Change the version number and package filename/directory in the documentation.
455 Change code examples in the documentation if appropriate.
456 Update the release notes (see above).
457 Check the setup.py file and ensure that all package directories are mentioned.
458 Check the release information in the PKG-INFO file and in the package
459 changelog (and other files).
460 Tag, export.
461 Generate the PyServlet classes.
462 Generate the API documentation.
463 Remove generated .pyc files: rm `find . -name "*.pyc"`
464 Archive, upload.
465 Upload the introductory documentation.
466 Update PyPI, PythonInfo Wiki entries.
467
468 Generating the PyServlet Classes
469 --------------------------------
470
471 In order to generate the PyServlet classes, it is necessary to run the
472 supplied script:
473
474 ./tools/JavaServlet/compile.sh
475
476 This produces Java classes and a .jar file for use by WebStack applications
477 running on the Java platform.
478
479 Generating the API Documentation
480 --------------------------------
481
482 In order to prepare the API documentation, it is necessary to generate some
483 Web pages from the Python source code. For this, the epydoc application must
484 be available on your system. Then, inside the distribution directory, run the
485 apidocs.sh tool script as follows:
486
487 ./tools/apidocs.sh
488
489 Some warnings may be generated by the script, but the result should be a new
490 apidocs directory within the distribution directory.
491
492 Making Packages
493 ---------------
494
495 To make Debian-based packages:
496
497 1. Create new package directories under packages if necessary.
498 2. Make a symbolic link in the distribution's root directory to keep the
499 Debian tools happy. For example, one of the following:
500
501 ln -s packages/ubuntu-hoary/python2.4-webstack/debian/
502 ln -s packages/ubuntu-feisty/python-webstack/debian/
503 ln -s packages/ubuntu-feisty/jython-webstack/debian/
504
505 3. Run the package builder:
506
507 dpkg-buildpackage -rfakeroot
508
509 4. Locate and tidy up the packages in the parent directory of the
510 distribution's root directory.