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1 # -*- coding: utf-8 -*- | |
2 # Copyright 2011 Google Inc. All Rights Reserved. | |
3 # Copyright 2011, Nexenta Systems Inc. | |
4 # | |
5 # Licensed under the Apache License, Version 2.0 (the "License"); | |
6 # you may not use this file except in compliance with the License. | |
7 # You may obtain a copy of the License at | |
8 # | |
9 # http://www.apache.org/licenses/LICENSE-2.0 | |
10 # | |
11 # Unless required by applicable law or agreed to in writing, software | |
12 # distributed under the License is distributed on an "AS IS" BASIS, | |
13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 # See the License for the specific language governing permissions and | |
15 # limitations under the License. | |
16 """Implementation of Unix-like cat command for cloud storage providers.""" | |
17 | |
18 from __future__ import absolute_import | |
19 | |
20 import re | |
21 | |
22 from gslib.cat_helper import CatHelper | |
23 from gslib.command import Command | |
24 from gslib.command_argument import CommandArgument | |
25 from gslib.cs_api_map import ApiSelector | |
26 from gslib.exception import CommandException | |
27 from gslib.util import NO_MAX | |
28 | |
29 _SYNOPSIS = """ | |
30 gsutil cat [-h] url... | |
31 """ | |
32 | |
33 _DETAILED_HELP_TEXT = (""" | |
34 <B>SYNOPSIS</B> | |
35 """ + _SYNOPSIS + """ | |
36 | |
37 | |
38 <B>DESCRIPTION</B> | |
39 The cat command outputs the contents of one or more URLs to stdout. | |
40 It is equivalent to doing: | |
41 | |
42 gsutil cp url... - | |
43 | |
44 (The final '-' causes gsutil to stream the output to stdout.) | |
45 | |
46 | |
47 <B>WARNING: DATA INTEGRITY CHECKING NOT DONE</B> | |
48 The gsutil cat command does not compute a checksum of the downloaded data. | |
49 Therefore, we recommend that users either perform their own validation of the | |
50 output of gsutil cat or use gsutil cp or rsync (both of which perform | |
51 integrity checking automatically). | |
52 | |
53 | |
54 <B>OPTIONS</B> | |
55 -h Prints short header for each object. For example: | |
56 | |
57 gsutil cat -h gs://bucket/meeting_notes/2012_Feb/*.txt | |
58 | |
59 This would print a header with the object name before the contents | |
60 of each text object that matched the wildcard. | |
61 | |
62 -r range Causes gsutil to output just the specified byte range of the | |
63 object. Ranges are can be of these forms: | |
64 | |
65 start-end (e.g., -r 256-5939) | |
66 start- (e.g., -r 256-) | |
67 -numbytes (e.g., -r -5) | |
68 | |
69 where offsets start at 0, start-end means to return bytes start | |
70 through end (inclusive), start- means to return bytes start | |
71 through the end of the object, and -numbytes means to return the | |
72 last numbytes of the object. For example: | |
73 | |
74 gsutil cat -r 256-939 gs://bucket/object | |
75 | |
76 returns bytes 256 through 939, while: | |
77 | |
78 gsutil cat -r -5 gs://bucket/object | |
79 | |
80 returns the final 5 bytes of the object. | |
81 """) | |
82 | |
83 | |
84 class CatCommand(Command): | |
85 """Implementation of gsutil cat command.""" | |
86 | |
87 # Command specification. See base class for documentation. | |
88 command_spec = Command.CreateCommandSpec( | |
89 'cat', | |
90 command_name_aliases=[], | |
91 usage_synopsis=_SYNOPSIS, | |
92 min_args=1, | |
93 max_args=NO_MAX, | |
94 supported_sub_args='hr:', | |
95 file_url_ok=False, | |
96 provider_url_ok=False, | |
97 urls_start_arg=0, | |
98 gs_api_support=[ApiSelector.XML, ApiSelector.JSON], | |
99 gs_default_api=ApiSelector.JSON, | |
100 argparse_arguments=[ | |
101 CommandArgument.MakeZeroOrMoreCloudURLsArgument() | |
102 ] | |
103 ) | |
104 # Help specification. See help_provider.py for documentation. | |
105 help_spec = Command.HelpSpec( | |
106 help_name='cat', | |
107 help_name_aliases=[], | |
108 help_type='command_help', | |
109 help_one_line_summary='Concatenate object content to stdout', | |
110 help_text=_DETAILED_HELP_TEXT, | |
111 subcommand_help_text={}, | |
112 ) | |
113 | |
114 # Command entry point. | |
115 def RunCommand(self): | |
116 """Command entry point for the cat command.""" | |
117 show_header = False | |
118 request_range = None | |
119 start_byte = 0 | |
120 end_byte = None | |
121 if self.sub_opts: | |
122 for o, a in self.sub_opts: | |
123 if o == '-h': | |
124 show_header = True | |
125 elif o == '-r': | |
126 request_range = a.strip() | |
127 range_matcher = re.compile( | |
128 '^(?P<start>[0-9]+)-(?P<end>[0-9]*)$|^(?P<endslice>-[0-9]+)$') | |
129 range_match = range_matcher.match(request_range) | |
130 if not range_match: | |
131 raise CommandException('Invalid range (%s)' % request_range) | |
132 if range_match.group('start'): | |
133 start_byte = long(range_match.group('start')) | |
134 if range_match.group('end'): | |
135 end_byte = long(range_match.group('end')) | |
136 if range_match.group('endslice'): | |
137 start_byte = long(range_match.group('endslice')) | |
138 else: | |
139 self.RaiseInvalidArgumentException() | |
140 | |
141 return CatHelper(self).CatUrlStrings(self.args, | |
142 show_header=show_header, | |
143 start_byte=start_byte, | |
144 end_byte=end_byte) | |
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