|
# coding=utf-8
#
# Copyright (C) 2010-2012 Platform Computing
#
# This library 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.
#
# This library is distributed 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 this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#
'''
Set of functions to parse stuff.
Created on Jun 28, 2011
@author: tmetsch
'''
# disabling 'Too many local variables' pylint check (text renderings :-()
# disabling 'Too many branches' pylint check (text renderings :-()
# pylint: disable=R0914,R0912
from occi.core_model import Category, Link, Mixin, Kind
#==============================================================================
# Following are text/occi and text/plain related parsing functions.
#==============================================================================
def get_category(category_string, registry, extras, is_mixin=False):
'''
Create a Category from a string rendering.
If found it will return the object from the registry.
If is_mixin is set to true it will not match with the registry and just
return a Mixin.
category_string -- A string rendering of a category.
registry -- To generate a list of registered categories.
extras -- The passed on extras argument
is_mixin -- Mixin will be created and no matching will be done.
'''
categories = registry.get_categories(extras)
# find term
term = category_string[:category_string.find(';')].strip()
# find scheme
scheme = find_in_string(category_string, 'scheme')
if is_mixin:
location = find_in_string(category_string, 'location')
if not location[-1] == '/':
raise AttributeError('Illegal location; must end with /')
if location[0] != '/' and location.find('http') != 0:
raise AttributeError('Illegal location; Either provide full URL'
' or just a path starting with /.')
mixin = Mixin(scheme, term, location=location)
mixin.extras = registry.get_extras(extras)
try:
related = find_in_string(category_string, 'rel')
except AttributeError:
return mixin
else:
for item in categories:
if str(item) == related:
mixin.related = [item]
return mixin
raise AttributeError('Related category cannot be found.')
# return the category from registry...
tmp = Category(scheme, term, '', {}, '')
if extras is not None:
tmp.extras = registry.get_extras(extras)
for item in categories:
if item.extras is None:
tmp.extras = None
if tmp == item:
del tmp
return item
tmp.extras = registry.get_extras(extras)
elif item.extras is not None:
if tmp == item:
del tmp
return item
raise AttributeError('The following category is not registered within'
+ ' this service (See Query interfaces): '
+ str(scheme) + str(term))
def get_category_str(category, registry):
'''
Create a string rendering for a Category.
category -- A category.
registry -- registry to retrieve hostname.
'''
tmp = ''
tmp += category.term
tmp += '; scheme="' + category.scheme + '"'
tmp += '; class="' + repr(category) + '"'
if hasattr(category, 'title') and category.title is not '':
tmp += '; title="' + category.title + '"'
if hasattr(category, 'related') and len(category.related) > 0:
rel_list = []
for item in category.related:
rel_list.append(str(item))
tmp += '; rel="' + ' '.join(rel_list) + '"'
if hasattr(category, 'location') and category.location is not None:
tmp += '; location="'
if category.location.find('http') == -1:
tmp += registry.get_hostname()
tmp += category.location + '"'
if hasattr(category, 'attributes') and len(category.attributes) > 0:
attr_list = []
for item in category.attributes:
if category.attributes[item] == 'required':
attr_list.append(item + '{required}')
elif category.attributes[item] == 'immutable':
attr_list.append(item + '{immutable}')
else:
attr_list.append(item)
tmp += '; attributes="' + ' '.join(attr_list) + '"'
if hasattr(category, 'actions') and len(category.actions) > 0:
action_list = []
for item in category.actions:
action_list.append(str(item))
tmp += '; actions="' + ' '.join(action_list) + '"'
return tmp
def _get_link_categories(categories, registry, extras):
'''
Determine the kind ans mixins for inline link creation.
categories -- String with a set of category string definitions.
registry -- Registry used for this call.
extras -- Passed on extra object.
'''
tmp_kind = None
tmp_mixins = []
for tmp_cat in categories.split(' '):
tempus = tmp_cat.split('#')
link_category = get_category(tempus[1].strip() + ';scheme="'
+ tempus[0].strip() + '#"', registry,
extras)
if isinstance(link_category, Kind):
tmp_kind = link_category
else:
tmp_mixins.append(link_category)
return tmp_kind, tmp_mixins
def get_link(link_string, source, registry, extras):
'''
Create a Link from a string rendering.
Also note that the link_id is set but is not yet registered as resource.
link_string -- A string rendering of a link.
source -- The source entity.
registry -- Registry used for this call.
extras -- Passed on extra object.
'''
tmp = link_string.find('<') + 1
target_id = link_string[tmp:link_string.rfind('>', tmp)].strip()
try:
link_id = find_in_string(link_string, 'self')
except AttributeError:
link_id = None
try:
tmp_category = find_in_string(link_string, 'category')
except AttributeError:
raise AttributeError('Could not determine the Category of the Link.')
tmp_kind, tmp_mixins = _get_link_categories(tmp_category, registry, extras)
if tmp_kind is None:
raise AttributeError('Unable to find the Kind of the Link.')
attributes = {}
attr_begin = link_string.find('category="') + 12 + len(tmp_category)
attributes_str = link_string[attr_begin:]
for attribute in attributes_str.split(';'):
tmp = attribute.strip().split('=')
if len(tmp) == 2:
attributes[tmp[0].strip()] = tmp[1].rstrip('"').lstrip('"').strip()
try:
if not target_id.find(registry.get_hostname()):
target_id = target_id.replace(registry.get_hostname(), '')
target = registry.get_resource(target_id, extras)
except KeyError:
# FUTURE_IMPROVEMENT: string links
raise AttributeError('The target for the link cannot be found: '
+ target_id)
link = Link(link_id, tmp_kind, tmp_mixins, source, target)
link.attributes = attributes
return link
def get_link_str(link):
'''
Create a string rendering for a Link.
link -- A link.
'''
tmp = '<' + link.target.identifier + '>'
tmp += '; rel="' + str(link.target.kind) + '"'
tmp += '; self="' + str(link.identifier) + '"'
tmp += '; category="' + str(link.kind)
if len(link.mixins) > 0:
for mixin in link.mixins:
tmp = tmp + ' ' + str(mixin)
tmp += '"'
link.attributes['occi.core.id'] = link.identifier
link.attributes['occi.core.source'] = link.source.identifier
# FUTURE_IMPROVEMENT: string links
link.attributes['occi.core.target'] = link.target.identifier
if len(link.attributes) > 0:
attr_str_list = []
for item in link.attributes:
attr_str_list.append(item + '="' + link.attributes[item] + '"')
tmp += '; ' + '; '.join(attr_str_list)
return tmp
def get_attributes(attribute_string):
'''
Retrieve the attributes from the HTTP X-OCCI-Attribute rendering.
'''
tmp = _strip_all(attribute_string)
if tmp.find('=') == -1:
raise AttributeError('Mailformed Attribute description!')
key = _strip_all(tmp[:tmp.find('=')])
value = tmp[tmp.find('=') + 1:]
if value.find('"') is not -1:
value = _strip_all(value)
return key, value
#==============================================================================
# Helpers
#==============================================================================
def _strip_all(string):
'''
Removes beginning / ending quotes and whitespaces.
'''
return string.lstrip().lstrip('"').rstrip().rstrip('"')
def find_in_string(string, name):
'''
Search for string which is surrounded by '<name>=' and ';'. Raises
AttributeError if value cannot be found.
string -- The string to look into.
name -- The name of the value to look for.
'''
begin = string.find(name + '=')
end = string.find(';', begin)
result = string[begin + len(name) + 1:end].rstrip('"').lstrip('"').strip()
if begin == -1:
raise AttributeError('Could not determine the value for: ' + name)
return result
|