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 Framework Support
12 -----------------
13
14 Currently, BaseHTTPRequestHandler (via BaseHTTPServer in the standard
15 library), CGI, Jython/Java Servlet API, mod_python, Twisted, Webware, WSGI
16 and Zope 2 are supported. Each framework has its own set of strengths and
17 weaknesses, but the idea is that deployment concerns can be considered
18 separately from the implementation of application functionality. Consult the
19 NOTES.txt files in each framework's subdirectory of the docs directory for
20 some notes on how applications may be run in each environment.
21
22 Tested Frameworks Release Information
23 ----------------- -------------------
24
25 BaseHTTPRequestHandler Python 2.2.2, Python 2.3.3
26 CGI Apache 2.0.44
27 Jython/Java Servlet API Jython 2.1, Java JDK 1.3.1_02, Tomcat 4.1.27 (Servlet 2.3)
28 mod_python 3.0.3 (3.1.3 for framework cookie and session support)
29 Twisted 1.0.5, 1.3.0
30 Webware 0.8.1, CVS (2004-02-06)
31 WSGI run_with_cgi (PEP 333)
32 Zope 2.7.2-0
33
34 New in WebStack 0.9 (Changes since WebStack 0.8)
35 ------------------------------------------------
36
37 Standardised error handling in the adapters so that tracebacks can be
38 suppressed and an internal server error condition raised.
39 Added overriding of path info in transactions.
40 Added a ResourceMap resource for dispatching to different resources
41 according to path components.
42 Standardised deployment for some frameworks (see docs/deploying.html).
43 Introductory documentation in XHTML format.
44 Added server name and port methods to the transaction.
45
46 New in WebStack 0.8 (Changes since WebStack 0.7)
47 ------------------------------------------------
48
49 Added a standard exception, EndOfResponse, which can be used to immediately
50 stop the processing/production of a response; this is useful when resources
51 need to issue a redirect without unnecessary content being generated, for
52 example.
53 Fixed path information for Zope.
54 Added WSGI support.
55 Verified Twisted 1.3.0 support with Python 2.3.3.
56
57 New in WebStack 0.7 (Changes since WebStack 0.6)
58 ------------------------------------------------
59
60 Fixed path information semantics.
61 Fixed file upload semantics.
62 Fixed content type handling for Unicode output and for interpreting request
63 body fields/parameters (although some improvement remains).
64 Added a method to discover the chosen response stream encoding.
65 Fixed field/parameter retrieval so that path and body fields are distinct,
66 regardless of the framework employed.
67 Added a method to get a combination of path and body fields (suggested by Jacob
68 Smullyan).
69 Introduced Zope 2 support.
70 Improved Jython/Java Servlet API support (although a special PyServlet class
71 must now be used, and certain libraries must be deployed with applications).
72 Introduced authentication/authorisation support for Jython/Java Servlet API.
73 Session support has been added (except for Webware 0.8.1).
74 Alternative cookie support for mod_python has been added.
75 Cookie support now supports encoded Unicode sequences for names and values.
76
77 New in WebStack 0.6 (Changes since WebStack 0.5)
78 ------------------------------------------------
79
80 Introduced Jython/Java Servlet API support.
81 Minor fixes to example applications and to BaseHTTPRequestHandler.
82
83 New in WebStack 0.5 (Changes since WebStack 0.4)
84 ------------------------------------------------
85
86 Changed request body fields/parameters so that they are now represented using
87 Unicode objects rather than plain strings.
88 Introduced better support for Unicode in response streams.
89
90 New in WebStack 0.4 (Changes since WebStack 0.3)
91 ------------------------------------------------
92
93 Added application definition of user identity, permitting alternative
94 authentication mechanisms.
95 Improved BaseHTTPRequestHandler and mod_python reliability around fields from
96 request bodies.
97 Provided stream and environment parameterisation in the CGI adapter.
98 Added LoginRedirect and Login examples.
99 Added get_path_without_query and fixed get_path behaviour.
100
101 New in WebStack 0.3 (Changes since WebStack 0.2)
102 ------------------------------------------------
103
104 Added better header support for Webware (suggested by Ian Bicking).
105 Introduced CGI and Java Servlet support (the latter is currently
106 broken/unfinished).
107 Introduced support for cookies.
108
109 Future Work
110 -----------
111
112 (Essential)
113
114 JythonServlet libraries need to be configured using sys.add_package when
115 these do not feature in the compiled-in list. Adding such configuration to
116 the handler may be most appropriate (since the web.xml file can be too
117 arcane), but this needs testing.
118
119 (Important)
120
121 Things to consider for future releases: improved cookie support, redirects,
122 access to shared resources and much better documentation.
123
124 Field access needs testing, especially for anything using the cgi.FieldStorage
125 class, and the way file uploads are exposed should be reviewed (currently the
126 meta-data is not exposed). The acquisition of fields from specific sources
127 should be tested with different request methods - some frameworks provide path
128 fields in the body fields dictionary, others (eg. Zope) change the fields
129 exposed depending on request method.
130
131 Interpretation of path field encodings needs to be verified. Currently, stray
132 path fields are handled (eg. in WebStack.Helpers.Request) as being ISO-8859-1,
133 but it might be the case that some such fields might be submitted as UTF-8.
134
135 Cookie objects need defining strictly, especially since the standard library
136 Cookie object behaves differently to mod_python (and possibly Webware) Cookie
137 objects. Moreover, the set_cookie_value method needs to provide access to the
138 usual cookie parameters as supported by the frameworks. The standard library
139 Cookie module has issues with Unicode cookie names (and possibly values) -
140 this is worked around, but it would be best to resolve this comprehensively.
141
142 UTF-16 (and possibly other encodings) causes problems with HTML form data sent
143 in POST requests using the application/x-www-form-urlencoded content type.
144 This should be reviewed at a later date when proper standardisation has taken
145 place.
146
147 Session support, especially through WebStack.Helpers.Session, should be
148 reviewed and be made compatible with non-cookie mechanisms.
149
150 HeaderValue objects should be employed more extensively. Thus, the header
151 access methods may need to change their behaviour slightly.
152
153 Investigate the nicer functions in the cgi module, discarding the "magic"
154 stuff like FieldStorage.
155
156 WSGI support could demand that a special "end of headers" method be
157 introduced into WebStack, thus making response output more efficient (and
158 probably also for other frameworks, too).
159
160 The algorithm employed in the WebStack.Helpers.Auth.get_token function should
161 be reviewed and improved for better security.
162
163 Investigate proper support for HEAD, OPTIONS and other request methods.
164
165 (Completed/rejected)
166
167 The location of deployed applications in the filesystem should be exposed to
168 those applications. (This is actually available in the __file__ module
169 variable.)
170
171 Path information should be consistent across all frameworks, and the "path
172 info" value should be meaningful. (This should now be correct.)
173
174 Release Procedures
175 ------------------
176
177 Update the WebStack/__init__.py __version__ attribute.
178 Change the version number and package filename/directory in the documentation.
179 Change code examples in the documentation if appropriate.
180 Update the release notes (see above).
181 Check the setup.py file and ensure that all package directories are mentioned.
182 Tag, export.
183 Generate the PyServlet classes.
184 Generate the API documentation.
185 Archive, upload.
186
187 Generating the API Documentation
188 --------------------------------
189
190 In order to prepare the API documentation, it is necessary to generate some Web
191 pages from the Python source code. For this, the epydoc application must be
192 available on your system. Then, inside the WebStack directory, run the
193 apidocs.sh tool script as follows:
194
195 ./tools/apidocs.sh
196
197 Some warnings may be generated by the script, but the result should be a new
198 apidocs directory within the WebStack directory.