1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
|
# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
# (c) 2005 Ian Bicking, Clark C. Evans and contributors
# This module is part of the Python Paste Project and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""
This module handles sending static content such as in-memory data or
files. At this time it has cache helpers and understands the
if-modified-since request header.
"""
import os, time, mimetypes
from paste.httpexceptions import *
from paste.httpheaders import *
CACHE_SIZE = 4096
BLOCK_SIZE = 4096 * 16
__all__ = ['DataApp', 'FileApp']
class DataApp(object):
"""
Returns an application that will send content in a single chunk,
this application has support for setting cashe-control and for
responding to conditional (or HEAD) requests.
Constructor Arguments:
``content`` the content being sent to the client
``headers`` the headers to send /w the response
The remaining ``kwargs`` correspond to headers, where the
underscore is replaced with a dash. These values are only
added to the headers if they are not already provided; thus,
they can be used for default values. Examples include, but
are not limited to:
``content_type``
``content_encoding``
``content_location``
``cache_control()``
This method provides validated construction of the ``Cache-Control``
header as well as providing for automated filling out of the
``EXPIRES`` header for HTTP/1.0 clients.
``set_content()``
This method provides a mechanism to set the content after the
application has been constructed. This method does things
like changing ``Last-Modified`` and ``Content-Length`` headers.
"""
def __init__(self, content, headers=None, **kwargs):
assert isinstance(headers, (type(None), list))
self.expires = None
self.content = None
self.content_length = None
self.last_modified = 0
self.headers = headers or []
for (k, v) in kwargs.items():
header = get_header(k)
header.update(self.headers, v)
ACCEPT_RANGES.update(self.headers, bytes=True)
if not CONTENT_TYPE(self.headers):
CONTENT_TYPE.update(self.headers)
if content is not None:
self.set_content(content)
def cache_control(self, **kwargs):
self.expires = CACHE_CONTROL.apply(self.headers, **kwargs) or None
return self
def set_content(self, content, last_modified=None):
assert content is not None
if last_modified is None:
self.last_modified = time.time()
else:
self.last_modified = last_modified
self.content = content
self.content_length = len(content)
LAST_MODIFIED.update(self.headers, time=self.last_modified)
return self
def content_disposition(self, **kwargs):
CONTENT_DISPOSITION.apply(self.headers, **kwargs)
return self
def __call__(self, environ, start_response):
method = environ['REQUEST_METHOD'].upper()
if method not in ('GET', 'HEAD'):
exc = HTTPMethodNotAllowed(
'You cannot %s a file' % method,
headers=[('Allow', 'GET, HEAD')])
return exc(environ, start_response)
return self.get(environ, start_response)
def get(self, environ, start_response):
headers = self.headers[:]
current_etag = str(self.last_modified)
ETAG.update(headers, current_etag)
if self.expires is not None:
EXPIRES.update(headers, delta=self.expires)
try:
client_clock = IF_MODIFIED_SINCE.parse(environ)
if client_clock >= int(self.last_modified):
# horribly inefficient, n^2 performance, yuck!
for head in list_headers(entity=True):
head.delete(headers)
start_response('304 Not Modified', headers)
return [''] # empty body
except HTTPBadRequest, exce:
return exce.wsgi_application(environ, start_response)
try:
client_etags = IF_NONE_MATCH.parse(environ)
if client_etags:
for etag in client_etags:
if etag == current_etag or etag == '*':
# horribly inefficient, n^2 performance, yuck!
for head in list_headers(entity=True):
head.delete(headers)
start_response('304 Not Modified', headers)
return ['']
except HTTPBadRequest, exce:
return exce.wsgi_application(environ, start_response)
(lower, upper) = (0, self.content_length - 1)
range = RANGE.parse(environ)
if range and 'bytes' == range[0] and 1 == len(range[1]):
(lower, upper) = range[1][0]
upper = upper or (self.content_length - 1)
if upper >= self.content_length or lower > upper:
return HTTPRequestRangeNotSatisfiable((
"Range request was made beyond the end of the content,\r\n"
"which is %s long.\r\n Range: %s\r\n") % (
self.content_length, RANGE(environ))
).wsgi_application(environ, start_response)
content_length = upper - lower + 1
CONTENT_RANGE.update(headers, first_byte=lower, last_byte=upper,
total_length = self.content_length)
CONTENT_LENGTH.update(headers, content_length)
if content_length == self.content_length:
start_response('200 OK', headers)
else:
start_response('206 Partial Content', headers)
if self.content is not None:
return [self.content[lower:upper+1]]
return (lower, content_length)
class FileApp(DataApp):
"""
Returns an application that will send the file at the given
filename. Adds a mime type based on ``mimetypes.guess_type()``.
See DataApp for the arguments beyond ``filename``.
"""
def __init__(self, filename, headers=None, **kwargs):
self.filename = filename
content_type, content_encoding = mimetypes.guess_type(self.filename)
if content_type and 'content_type' not in kwargs:
kwargs['content_type'] = content_type
if content_encoding and 'content_encoding' not in kwargs:
kwargs['content_encoding'] = content_encoding
DataApp.__init__(self, None, headers, **kwargs)
def update(self, force=False):
stat = os.stat(self.filename)
if not force and stat.st_mtime == self.last_modified:
return
self.last_modified = stat.st_mtime
if stat.st_size < CACHE_SIZE:
fh = open(self.filename,"rb")
self.set_content(fh.read(), stat.st_mtime)
fh.close()
else:
self.content = None
self.content_length = stat.st_size
# This is updated automatically if self.set_content() is
# called
LAST_MODIFIED.update(self.headers, time=self.last_modified)
def get(self, environ, start_response):
is_head = environ['REQUEST_METHOD'].upper() == 'HEAD'
if 'max-age=0' in CACHE_CONTROL(environ).lower():
self.update(force=True) # RFC 2616 13.2.6
else:
self.update()
if not self.content:
if not os.path.exists(self.filename):
exc = HTTPNotFound(
'The resource does not exist',
comment="No file at %r" % self.filename)
return exc(environ, start_response)
try:
file = open(self.filename, 'rb')
except (IOError, OSError), e:
exc = HTTPForbidden(
'You are not permitted to view this file (%s)' % e)
return exc.wsgi_application(
environ, start_response)
retval = DataApp.get(self, environ, start_response)
if isinstance(retval, list):
# cached content, exception, or not-modified
if is_head:
return ['']
return retval
(lower, content_length) = retval
if is_head:
return ['']
file.seek(lower)
return _FileIter(file, size=content_length)
class _FileIter(object):
def __init__(self, file, block_size=None, size=None):
self.file = file
self.size = size
self.block_size = block_size or BLOCK_SIZE
def __iter__(self):
return self
def next(self):
chunk_size = self.block_size
if self.size is not None:
if chunk_size > self.size:
chunk_size = self.size
self.size -= chunk_size
data = self.file.read(chunk_size)
if not data:
raise StopIteration
return data
def close(self):
self.file.close()
|
