# $SnapHashLicense:
#
# SnapLogic - Open source data services
#
# Copyright (C) 2008 SnapLogic, Inc. All rights reserved.
#
# See http://www.snaplogic.org for more information about
# the SnapLogic project.
#
# This program is free software, distributed under the terms of
# the GNU General Public License Version 2. See the LEGAL file
# at the top of the source tree.
#
# "SnapLogic" is a trademark of SnapLogic, Inc.
#
#
# $
# $Id: packaging.py 5561 2008-12-02 00:25:19Z kurt $
"""
Repository API for import/export packaging.
In order to allow for full backwards compatibility with previous repository export formats, the packaging
code for importing and exporting is contained here within the repository API. All code related to multipe
repository version handling should therefore remain in the repository module.
"""
import simplejson
from snaplogic import rp
from snaplogic.common.snap_exceptions import *
from snaplogic.common import version_info
from snaplogic.snapi_base import keys
HEADER_TAG = 'package header'
class PackageWriter(object):
"""
Write a repository export package to a stream.
A wrapper around a stream-like object to write out a repository package. Version information is
included in the package to assure its integrity on import to other version of the software.
"""
def __init__(self, stream):
"""
Initialization.
@param stream: A stream-like object.
@type stream: object
"""
srp = rp.get_rp('application/json')
self._writer = srp.Writer(stream)
self._writer.initialize()
self._writer.write([HEADER_TAG, version_info.repository_packaging_version])
def write_resource(self, uri, resdef):
"""
Write a single resource out to the package.
@param uri: URI of resource.
@type uri: string
@param resdef: A ResDef dictionary.
@type resdef: dict
"""
self._writer.write([uri, resdef])
def end(self):
"""
End the package writing and complete package.
"""
self._writer.end()
class PackageReader(object):
"""
Open a repository export package for reading resources.
A wrapper around a stream-like object to read in a repository package and decode it properly.
Version compatibility with previous supported versions is handled automatically. The various
read methods will return resdef dictionaries suitable for the current version of the product.
"""
def __init__(self, stream):
"""
Initialization.
@param stream: A stream-like object.
@type stream: object
@raise SnapRepInvalidPackageError: The package contained in the stream is invalid, corrupted, or
from an incompatible version.
"""
srp = rp.get_rp('application/json')
self._reader = srp.Reader(stream)
header = self._reader.next()
try:
if header[0] != HEADER_TAG:
raise SnapRepInvalidPackageError("header tag missing.")
elif header[1] != version_info.repository_packaging_version:
# Since no changes to the packaging format have happened yet, we just need to worry about
# server versions greater than the current version.
raise SnapRepInvalidPackageError("version is incompatible.")
except SnapRepError:
raise
except Exception, e:
raise SnapException.chain(e, SnapRepInvalidPackageError("missing or corrupt package header."))
self.repo_version = header[1]
def read_resource(self):
"""
Read a single resource from the package.
@return: A tuple of (uri, resdef) with the resdef being a ResDef dictionary. Returns None when
all resources have been read.
@rtype: tuple
"""
try:
return tuple(self._reader.next())
except StopIteration:
return None
def read_resources(self):
"""
Read all resources remaining in the package.
@return: A list of tuples (uri, resdef) with the resdef being a ResDef dictionary.
@rtype: list
"""
resources = []
for (uri, resdef) in self:
resources.append((uri, resdef))
return resources
def __iter__(self):
"""
Ierator to read remaining resources.
"""
try:
while True:
yield tuple(self._reader.next())
except StopIteration:
pass
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