"""
HTTP Utilities
(from web.py)
"""
__all__ = [
"expires", "lastmodified",
"prefixurl", "modified",
"changequery", "url",
"profiler",
]
import sys, os, threading, urllib, urlparse
try: import datetime
except ImportError: pass
import net, utils, webapi as web
def prefixurl(base=''):
"""
Sorry, this function is really difficult to explain.
Maybe some other time.
"""
url = web.ctx.path.lstrip('/')
for i in xrange(url.count('/')):
base += '../'
if not base:
base = './'
return base
def expires(delta):
"""
Outputs an `Expires` header for `delta` from now.
`delta` is a `timedelta` object or a number of seconds.
"""
if isinstance(delta, (int, long)):
delta = datetime.timedelta(seconds=delta)
date_obj = datetime.datetime.utcnow() + delta
web.header('Expires', net.httpdate(date_obj))
def lastmodified(date_obj):
"""Outputs a `Last-Modified` header for `datetime`."""
web.header('Last-Modified', net.httpdate(date_obj))
def modified(date=None, etag=None):
"""
Checks to see if the page has been modified since the version in the
requester's cache.
When you publish pages, you can include `Last-Modified` and `ETag`
with the date the page was last modified and an opaque token for
the particular version, respectively. When readers reload the page,
the browser sends along the modification date and etag value for
the version it has in its cache. If the page hasn't changed,
the server can just return `304 Not Modified` and not have to
send the whole page again.
This function takes the last-modified date `date` and the ETag `etag`
and checks the headers to see if they match. If they do, it returns
`True` and sets the response status to `304 Not Modified`. It also
sets `Last-Modified and `ETag` output headers.
"""
try:
from __builtin__ import set
except ImportError:
# for python 2.3
from sets import Set
n = set([x.strip('" ') for x in web.ctx.env.get('HTTP_IF_NONE_MATCH', '').split(',')])
m = net.parsehttpdate(web.ctx.env.get('HTTP_IF_MODIFIED_SINCE', '').split(';')[0])
validate = False
if etag:
if '*' in n or etag in n:
validate = True
if date and m:
# we subtract a second because
# HTTP dates don't have sub-second precision
if date-datetime.timedelta(seconds=1) <= m:
validate = True
if validate: web.ctx.status = '304 Not Modified'
if date: lastmodified(date)
if etag: web.header('ETag', '"' + etag + '"')
return not validate
def urlencode(query, doseq=0):
"""
Same as urllib.urlencode, but supports unicode strings.
>>> urlencode({'text':'foo bar'})
'text=foo+bar'
>>> urlencode({'x': [1, 2]}, doseq=True)
'x=1&x=2'
"""
def convert(value, doseq=False):
if doseq and isinstance(value, list):
return [convert(v) for v in value]
else:
return utils.utf8(value)
query = dict([(k, convert(v, doseq)) for k, v in query.items()])
return urllib.urlencode(query, doseq=doseq)
def changequery(query=None, **kw):
"""
Imagine you're at `/foo?a=1&b=2`. Then `changequery(a=3)` will return
`/foo?a=3&b=2` -- the same URL but with the arguments you requested
changed.
"""
if query is None:
query = web.rawinput(method='get')
for k, v in kw.iteritems():
if v is None:
query.pop(k, None)
else:
query[k] = v
out = web.ctx.path
if query:
out += '?' + urlencode(query, doseq=True)
return out
def url(path=None, **kw):
"""
Makes url by concatinating web.ctx.homepath and path and the
query string created using the arguments.
"""
if path is None:
path = web.ctx.path
if path.startswith("/"):
out = web.ctx.homepath + path
else:
out = path
if kw:
out += '?' + urlencode(kw)
return out
def profiler(app):
"""Outputs basic profiling information at the bottom of each response."""
from utils import profile
def profile_internal(e, o):
out, result = profile(app)(e, o)
return list(out) + ['<pre>' + net.websafe(result) + '</pre>']
return profile_internal
if __name__ == "__main__":
import doctest
doctest.testmod()
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