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
|
# Copyright (C) 2003-2005 Robey Pointer <robey@lag.net>
#
# This file is part of paramiko.
#
# Paramiko is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# Paramiko is distrubuted in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
"""
L{SFTPFile}
"""
from paramiko.common import *
from paramiko.sftp import *
from paramiko.file import BufferedFile
from paramiko.sftp_attr import SFTPAttributes
class SFTPFile (BufferedFile):
"""
Proxy object for a file on the remote server, in client mode SFTP.
"""
# Some sftp servers will choke if you send read/write requests larger than
# this size.
MAX_REQUEST_SIZE = 32768
def __init__(self, sftp, handle, mode='r', bufsize=-1):
BufferedFile.__init__(self)
self.sftp = sftp
self.handle = handle
BufferedFile._set_mode(self, mode, bufsize)
self.pipelined = False
def __del__(self):
self.close()
def close(self):
# We allow double-close without signaling an error, because real
# Python file objects do. However, we must protect against actually
# sending multiple CMD_CLOSE packets, because after we close our
# handle, the same handle may be re-allocated by the server, and we
# may end up mysteriously closing some random other file. (This is
# especially important because we unconditionally call close() from
# __del__.)
if self._closed:
return
if self.pipelined:
self.sftp._finish_responses()
BufferedFile.close(self)
try:
self.sftp._request(CMD_CLOSE, self.handle)
except EOFError:
# may have outlived the Transport connection
pass
except IOError:
# may have outlived the Transport connection
pass
def _read(self, size):
size = min(size, self.MAX_REQUEST_SIZE)
t, msg = self.sftp._request(CMD_READ, self.handle, long(self._realpos), int(size))
if t != CMD_DATA:
raise SFTPError('Expected data')
return msg.get_string()
def _write(self, data):
# may write less than requested if it would exceed max packet size
chunk = min(len(data), self.MAX_REQUEST_SIZE)
self.sftp._async_request(CMD_WRITE, self.handle, long(self._realpos), str(data[:chunk]))
if not self.pipelined or self.sftp.sock.recv_ready():
t, msg = self.sftp._read_response()
if t != CMD_STATUS:
raise SFTPError('Expected status')
self.sftp._convert_status(msg)
return chunk
def settimeout(self, timeout):
"""
Set a timeout on read/write operations on the underlying socket or
ssh L{Channel}.
@see: L{Channel.settimeout}
@param timeout: seconds to wait for a pending read/write operation
before raising C{socket.timeout}, or C{None} for no timeout
@type timeout: float
"""
self.sftp.sock.settimeout(timeout)
def gettimeout(self):
"""
Returns the timeout in seconds (as a float) associated with the socket
or ssh L{Channel} used for this file.
@see: L{Channel.gettimeout}
@rtype: float
"""
return self.sftp.sock.gettimeout()
def setblocking(self, blocking):
"""
Set blocking or non-blocking mode on the underiying socket or ssh
L{Channel}.
@see: L{Channel.setblocking}
@param blocking: 0 to set non-blocking mode; non-0 to set blocking
mode.
@type blocking: int
"""
self.sftp.sock.setblocking(blocking)
def seek(self, offset, whence=0):
self.flush()
if whence == self.SEEK_SET:
self._realpos = self._pos = offset
elif whence == self.SEEK_CUR:
self._pos += offset
self._realpos = self._pos
else:
self._realpos = self._pos = self._get_size() + offset
self._rbuffer = ''
def stat(self):
"""
Retrieve information about this file from the remote system. This is
exactly like L{SFTP.stat}, except that it operates on an already-open
file.
@return: an object containing attributes about this file.
@rtype: SFTPAttributes
"""
t, msg = self.sftp._request(CMD_FSTAT, self.handle)
if t != CMD_ATTRS:
raise SFTPError('Expected attributes')
return SFTPAttributes._from_msg(msg)
def check(self, hash_algorithm, offset=0, length=0, block_size=0):
"""
Ask the server for a hash of a section of this file. This can be used
to verify a successful upload or download, or for various rsync-like
operations.
The file is hashed from C{offset}, for C{length} bytes. If C{length}
is 0, the remainder of the file is hashed. Thus, if both C{offset}
and C{length} are zero, the entire file is hashed.
Normally, C{block_size} will be 0 (the default), and this method will
return a byte string representing the requested hash (for example, a
string of length 16 for MD5, or 20 for SHA-1). If a non-zero
C{block_size} is given, each chunk of the file (from C{offset} to
C{offset + length}) of C{block_size} bytes is computed as a separate
hash. The hash results are all concatenated and returned as a single
string.
For example, C{check('sha1', 0, 1024, 512)} will return a string of
length 40. The first 20 bytes will be the SHA-1 of the first 512 bytes
of the file, and the last 20 bytes will be the SHA-1 of the next 512
bytes.
@param hash_algorithm: the name of the hash algorithm to use (normally
C{"sha1"} or C{"md5"})
@type hash_algorithm: str
@param offset: offset into the file to begin hashing (0 means to start
from the beginning)
@type offset: int or long
@param length: number of bytes to hash (0 means continue to the end of
the file)
@type length: int or long
@param block_size: number of bytes to hash per result (must not be less
than 256; 0 means to compute only one hash of the entire segment)
@type block_size: int
@return: string of bytes representing the hash of each block,
concatenated together
@rtype: str
@note: Many (most?) servers don't support this extension yet.
@raise IOError: if the server doesn't support the "check-file"
extension, or possibly doesn't support the hash algorithm
requested
@since: 1.4
"""
t, msg = self.sftp._request(CMD_EXTENDED, 'check-file', self.handle,
hash_algorithm, long(offset), long(length), block_size)
ext = msg.get_string()
alg = msg.get_string()
data = msg.get_remainder()
return data
def set_pipelined(self, pipelined=True):
"""
Turn on/off the pipelining of write operations to this file. When
pipelining is on, paramiko won't wait for the server response after
each write operation. Instead, they're collected as they come in.
At the first non-write operation (including L{close}), all remaining
server responses are collected. This means that if there was an error
with one of your later writes, an exception might be thrown from
within L{close} instead of L{write}.
By default, files are I{not} pipelined.
@param pipelined: C{True} if pipelining should be turned on for this
file; C{False} otherwise
@type pipelined: bool
@since: 1.5
"""
self.pipelined = pipelined
### internals...
def _get_size(self):
try:
return self.stat().st_size
except:
return 0
|
