Scripts to download files from google storage based on sha1 sums

third_party/gsutil/gslib/commands/cat.py

+# Copyright 2011 Google Inc.
+# Copyright 2011, Nexenta Systems Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+
+from gslib.command import Command
+from gslib.command import COMMAND_NAME
+from gslib.command import COMMAND_NAME_ALIASES
+from gslib.command import CONFIG_REQUIRED
+from gslib.command import FILE_URIS_OK
+from gslib.command import MAX_ARGS
+from gslib.command import MIN_ARGS
+from gslib.command import PROVIDER_URIS_OK
+from gslib.command import SUPPORTED_SUB_ARGS
+from gslib.command import URIS_START_ARG
+from gslib.exception import CommandException
+from gslib.help_provider import HELP_NAME
+from gslib.help_provider import HELP_NAME_ALIASES
+from gslib.help_provider import HELP_ONE_LINE_SUMMARY
+from gslib.help_provider import HELP_TEXT
+from gslib.help_provider import HelpType
+from gslib.help_provider import HELP_TYPE
+from gslib.util import NO_MAX
+from gslib.wildcard_iterator import ContainsWildcard
+
+_detailed_help_text = ("""
+<B>SYNOPSIS</B>
+  gsutil cat [-h] uri...
+
+
+<B>DESCRIPTION</B>
+  The cat command outputs the contents of one or more URIs to stdout.
+  It is equivalent to doing:
+
+    gsutil cp uri... -
+
+  (The final '-' causes gsutil to stream the output to stdout.)
+
+
+<B>OPTIONS</B>
+  -h          Prints short header for each object. For example:
+                gsutil cat -h gs://bucket/meeting_notes/2012_Feb/*.txt
+
+  -v          Parses uris for version / generation numbers (only applicable in 
+              version-enabled buckets). For example:
+
+                gsutil cat -v gs://bucket/object#1348772910166003
+
+              Note that wildcards are not permitted while using this flag.
+""")
+
+
+class CatCommand(Command):
+  """Implementation of gsutil cat command."""
+
+  # Command specification (processed by parent class).
+  command_spec = {
+    # Name of command.
+    COMMAND_NAME : 'cat',
+    # List of command name aliases.
+    COMMAND_NAME_ALIASES : [],
+    # Min number of args required by this command.
+    MIN_ARGS : 0,
+    # Max number of args required by this command, or NO_MAX.
+    MAX_ARGS : NO_MAX,
+    # Getopt-style string specifying acceptable sub args.
+    SUPPORTED_SUB_ARGS : 'hv',
+    # True if file URIs acceptable for this command.
+    FILE_URIS_OK : False,
+    # True if provider-only URIs acceptable for this command.
+    PROVIDER_URIS_OK : False,
+    # Index in args of first URI arg.
+    URIS_START_ARG : 0,
+    # True if must configure gsutil before running command.
+    CONFIG_REQUIRED : True,
+  }
+  help_spec = {
+    # Name of command or auxiliary help info for which this help applies.
+    HELP_NAME : 'cat',
+    # List of help name aliases.
+    HELP_NAME_ALIASES : [],
+    # Type of help:
+    HELP_TYPE : HelpType.COMMAND_HELP,
+    # One line summary of this help.
+    HELP_ONE_LINE_SUMMARY : 'Concatenate object content to stdout',
+    # The full help text.
+    HELP_TEXT : _detailed_help_text,
+  }
+
+  def VersionedSrcUriIter(self):
+    for uri_str in self.args:
+      if ContainsWildcard(uri_str):
+        raise CommandException('Wildcarding disallowed with -v flag.')
+      yield self.suri_builder.StorageUri(uri_str, parse_version=True)
+
+  def UnVersionedSrcUriIter(self):
+    for uri_str in self.args:
+      for uri in self.WildcardIterator(uri_str).IterUris():
+        yield uri
+
+  # Command entry point.
+  def RunCommand(self):
+    show_header = False
+    parse_versions = False
+    if self.sub_opts:
+      for o, unused_a in self.sub_opts:
+        if o == '-h':
+          show_header = True
+        elif o == '-v':
+          parse_versions = True
+
+    printed_one = False
+    # We manipulate the stdout so that all other data other than the Object
+    # contents go to stderr.
+    cat_outfd = sys.stdout
+    sys.stdout = sys.stderr
+    did_some_work = False
+
+    if parse_versions:
+      uri_iter = self.VersionedSrcUriIter
+    else:
+      uri_iter = self.UnVersionedSrcUriIter
+
+    for uri in uri_iter():
+      if not uri.names_object():
+        raise CommandException('"%s" command must specify objects.' %
+                               self.command_name)
+      did_some_work = True
+      if show_header:
+        if printed_one:
+          print
+        print '==> %s <==' % uri.__str__()
+        printed_one = True
+      key = uri.get_key(False, self.headers)
+      if not parse_versions:
+        key.generation = None
+      key.get_file(cat_outfd, self.headers)
+    sys.stdout = cat_outfd
+    if not did_some_work:
+      raise CommandException('No URIs matched')
+
+    return 0