python-peps/pep-0222.txt

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PEP: 222
Title: Web Library Enhancements
Version: $Revision$
Author: akuchlin@mems-exchange.org (Andrew Kuchling)
Status: Active
Type: Standards Track
Python-Version: 2.1
Created: 18-Aug-2000
Post-History:
Abstract
This PEP proposes a set of enhancements to the CGI development
facilities in the Python standard library. Enhancements might be
new features, new modules for tasks such as cookie support, or
removal of obsolete code.
The intent is to incorporate the proposals emerging from this
document into Python 2.1, due to be released in the first half of
2001.
Proposed Changes
This section lists changes that have been suggested, but about
which no firm decision has yet been made. In the final version of
this PEP, this section should be empty, as all the changes should
be classified as accepted or rejected.
fcgi.py : A new module adding support for the FastCGI protocol
Better debugging support for CGIs from the Unix command line.
Using Perl's CGI.pm [1], if you run a script from the command
line, you can enter name=value pairs on standard input.
cgimodel [2] provides this already.
Should the existing cgi.py be deprecated and everything moved into
a 'web' or 'cgi' package? That would allow removing some
backward-compatibility cruft.
cgi.py: keep_blank_values should be on by default. The 'if
form.has_key()/if form[key].value' nested syntax is unnecessarily
convoluted.
cgi.py: We should not be told to create our own subclass just so
we can handle file uploads. As a practical matter, I have yet to
find the time to do this right, so I end up reading cgi.py's temp
file into, at best, another file. Some of our legacy code actually
reads it into a second temp file, then into a final destination!
And even if we did, that would mean creating yet another object
with its __init__ call and associated overhead.
cgi.py: Delete the references to self.lines for file uploads
cgi.py: Ideally, the pseudo-dictionary syntax would go away. It
seems to me that the main reason it is there is to accomodate
form['field'].file syntax. How about the following:
form['field'] = '' #no values for key
form['field'] = 'string' #one value in submission for key
form['field'] = ['string', 'string', ....] #multiple values
form['field'] = {'fileName':'remote/path',
'binaryValue':'@UIHJBV29489erht...'} #one file
form['field'] = [{'fileName':'remote/path',
'binaryValue':'@UIHJBV29489erht...'},
{'fileName':'another/path',
'binaryValue':'7r7w7@@@@'}] #multiple files
cgi.py: I'd prefer "input" or "submission" for the suggested
FieldStorage() name. The html page into which the data represented
by FieldStorage() is input is commonly known as a "form", which
means that when someone refers to "the form" you aren't always
sure what they are talking about.
cgi.py: Allow a combination of query data and POST data.
Currently, if there is POST data, then any query data encoded in
the URL is ignored. It would be more convenient if the data from
those two sources were merged into one dictionary. (XXX but is
this standard at all?)
cgi.py: Currently, query data with no `=' are ignored. Even if
keep_blank_values is set, queries like `...?value=&...' are
returned with blank values but queries like `...?value&...' are
completely lost. It would be great if such data were made
available through the FieldStorage interface, either as entries
with None as values, or in a separate list.
Utility function: build a query string from a list of 2-tuples
Higher-level frameworks: add something like Webware or Zope's
HTTPReqest/HTTPResponse objects.
An HTML templating module. (But which one? There's no clear, or
even vague, indication of which templating module to enshrine.)
Dictionary-related utility classes: NoKeyErrors (returns an empty
string, never a KeyError), PartialStringSubstitution (returns
the original key string, never a KeyError)
New Modules
This section lists details about entire new packages or modules
that should be added to the Python standard library.
Major Changes to Existing Modules
This section lists details of major changes to existing modules,
whether in implementation or in interface. The changes in this
section therefore carry greater degrees of risk, either in
introducing bugs or a backward incompatibility.
Minor Changes to Existing Modules
This section lists details of minor changes to existing modules.
These changes should have relatively small implementations, and
have little risk of introducing incompatibilities with previous
versions.
Rejected Changes
The changes listed in this section were proposed for Python 2.1,
but were rejected as unsuitable. For each rejected change, a
rationale is given describing why the change was deemed
inappropriate.
* None yet
Proposed Interface
XXX open issues: naming convention (studlycaps or underline-separated?);
no interface for file uploads yet; need to look at all the various
packages to see if there's anything else missing; need to look at
the cgi.parse*() functions and see if they can be simplified, too.
Parsing functions: carry over most of the parse* functions from cgi.py
# The Response class borrows most of its methods from Zope's
# HTTPResponse class.
class Response:
"""
Attributes:
status: HTTP status code to return
headers: dictionary of response headers
body: string containing the body of the HTTP response
"""
def __init__(self, status=200, headers={}, body=""):
pass
def setStatus(self, status, reason=None):
"Set the numeric HTTP response code"
pass
def setHeader(self, name, value):
"Set an HTTP header"
pass
def setBody(self, body):
"Set the body of the response"
pass
def setCookie(self, name, value,
path = XXX, # What to use as defaults?
comment = XXX,
domain = XXX,
max-age = XXX,
expires = XXX,
secure = XXX
):
"Set a cookie"
pass
def expireCookie(self, name):
"Remove a cookie from the user"
pass
def redirect(self, url):
"Redirect the browser to another URL"
pass
def __str__(self):
"Convert entire response to a string"
pass
def dump(self):
"Return a string representation useful for debugging"
pass
# XXX methods for specific classes of error:serverError, badRequest, etc.?
class Request:
"""
Attributes:
.headers : dictionary containing HTTP headers
.cookies : dictionary of cookies
.form : data from the form
.env : environment dictionary
"""
def __init__(self, environ=os.environ, stdin=sys.stdin,
keep_blank_values=0, strict_parsing=0):
"""Initialize the request object, using the provided environment
and standard input."""
pass
# Should people just use the dictionaries directly?
def getHeader(self, name, default=None):
pass
def getCookie(self, name, default=None):
pass
def getField(self, name, default=None):
pass
def getURL(self, n=0, query_string=0):
"""Return the URL of the current request, chopping off 'n' path
components from the right. Eg. if the URL is
"http://foo.com/bar/baz/qux", n=2 would return
"http://foo.com/bar". Does not include the query string (if
any)
"""
def getBaseURL(self, n=0):
"""Return the base URL of the current request, adding 'n' path
components to the end to recreate more of the whole URL.
Eg. if the request URL is
"http://foo.com/q/bar/baz/qux", n=0 would return
"http://foo.com/", and n=2 "http://foo.com/q/bar".
Returned URL does not include the query string, if any.
"""
def dump(self):
"String representation suitable for debugging output"
pass
# Possibilities?
def getBrowser(self):
"Returns Mozilla/IE/Lynx/Opera/whatever"
def isSecure(self):
"Return true if this is an SSLified request"
def wrapper(func, logfile=None):
"""
Calls the function 'func', passing it the arguments
(request, response, logfile). Exceptions are trapped and
sent to the file 'logfile'.
"""
pass
Copyright
This document has been placed in the public domain.
References and Footnotes
[1] CGI.pm:
[2] http://www.embl-heidelberg.de/~chenna/pythonpages/
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