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
43 New in WebStack 0.8 (Changes since WebStack 0.7)
44 ------------------------------------------------
45
46 Added a standard exception, EndOfResponse, which can be used to immediately
47 stop the processing/production of a response; this is useful when resources
48 need to issue a redirect without unnecessary content being generated, for
49 example.
50 Fixed path information for Zope.
51 Added WSGI support.
52 Verified Twisted 1.3.0 support with Python 2.3.3.
53
54 New in WebStack 0.7 (Changes since WebStack 0.6)
55 ------------------------------------------------
56
57 Fixed path information semantics.
58 Fixed file upload semantics.
59 Fixed content type handling for Unicode output and for interpreting request
60 body fields/parameters (although some improvement remains).
61 Added a method to discover the chosen response stream encoding.
62 Fixed field/parameter retrieval so that path and body fields are distinct,
63 regardless of the framework employed.
64 Added a method to get a combination of path and body fields (suggested by Jacob
65 Smullyan).
66 Introduced Zope 2 support.
67 Improved Jython/Java Servlet API support (although a special PyServlet class
68 must now be used, and certain libraries must be deployed with applications).
69 Introduced authentication/authorisation support for Jython/Java Servlet API.
70 Session support has been added (except for Webware 0.8.1).
71 Alternative cookie support for mod_python has been added.
72 Cookie support now supports encoded Unicode sequences for names and values.
73
74 New in WebStack 0.6 (Changes since WebStack 0.5)
75 ------------------------------------------------
76
77 Introduced Jython/Java Servlet API support.
78 Minor fixes to example applications and to BaseHTTPRequestHandler.
79
80 New in WebStack 0.5 (Changes since WebStack 0.4)
81 ------------------------------------------------
82
83 Changed request body fields/parameters so that they are now represented using
84 Unicode objects rather than plain strings.
85 Introduced better support for Unicode in response streams.
86
87 New in WebStack 0.4 (Changes since WebStack 0.3)
88 ------------------------------------------------
89
90 Added application definition of user identity, permitting alternative
91 authentication mechanisms.
92 Improved BaseHTTPRequestHandler and mod_python reliability around fields from
93 request bodies.
94 Provided stream and environment parameterisation in the CGI adapter.
95 Added LoginRedirect and Login examples.
96 Added get_path_without_query and fixed get_path behaviour.
97
98 New in WebStack 0.3 (Changes since WebStack 0.2)
99 ------------------------------------------------
100
101 Added better header support for Webware (suggested by Ian Bicking).
102 Introduced CGI and Java Servlet support (the latter is currently
103 broken/unfinished).
104 Introduced support for cookies.
105
106 Future Work
107 -----------
108
109 (Essential)
110
111 JythonServlet libraries need to be configured using sys.add_package when
112 these do not feature in the compiled-in list. Adding such configuration to
113 the handler may be most appropriate (since the web.xml file can be too
114 arcane), but this needs testing.
115
116 (Important)
117
118 Things to consider for future releases: improved cookie support, redirects,
119 access to shared resources and much better documentation.
120
121 Field access needs testing, especially for anything using the cgi.FieldStorage
122 class, and the way file uploads are exposed should be reviewed (currently the
123 meta-data is not exposed). The acquisition of fields from specific sources
124 should be tested with different request methods - some frameworks provide path
125 fields in the body fields dictionary, others (eg. Zope) change the fields
126 exposed depending on request method.
127
128 Interpretation of path field encodings needs to be verified. Currently, stray
129 path fields are handled (eg. in WebStack.Helpers.Request) as being ISO-8859-1,
130 but it might be the case that some such fields might be submitted as UTF-8.
131
132 Cookie objects need defining strictly, especially since the standard library
133 Cookie object behaves differently to mod_python (and possibly Webware) Cookie
134 objects. Moreover, the set_cookie_value method needs to provide access to the
135 usual cookie parameters as supported by the frameworks. The standard library
136 Cookie module has issues with Unicode cookie names (and possibly values) -
137 this is worked around, but it would be best to resolve this comprehensively.
138
139 UTF-16 (and possibly other encodings) causes problems with HTML form data sent
140 in POST requests using the application/x-www-form-urlencoded content type.
141 This should be reviewed at a later date when proper standardisation has taken
142 place.
143
144 Session support, especially through WebStack.Helpers.Session, should be
145 reviewed and be made compatible with non-cookie mechanisms.
146
147 The location of deployed applications in the filesystem should be exposed to
148 those applications.
149
150 Path information should be consistent across all frameworks, and the "path
151 info" value should be meaningful.
152
153 HeaderValue objects should be employed more extensively. Thus, the header
154 access methods may need to change their behaviour slightly.
155
156 Investigate the nicer functions in the cgi module, discarding the "magic"
157 stuff like FieldStorage.
158
159 WSGI support could demand that a special "end of headers" method be
160 introduced into WebStack, thus making response output more efficient (and
161 probably also for other frameworks, too).
162
163 Release Procedures
164 ------------------
165
166 Update the WebStack/__init__.py __version__ attribute.
167 Update the release notes (see above).
168 Check the setup.py file and ensure that all package directories are mentioned.
169 Tag, export.
170 Generate the PyServlet classes.
171 Archive, upload.