code.grnet.gr Git - pithos/blob - pithos/backends/lib_alchemy/permissions.py

   1 # Copyright 2011 GRNET S.A. All rights reserved.
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   8 #      copyright notice, this list of conditions and the following
   9 #      disclaimer.
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  12 #      copyright notice, this list of conditions and the following
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  15 #
  16 # THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
  17 # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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  31 # interpreted as representing official policies, either expressed
  32 # or implied, of GRNET S.A.
  33
  34 from sqlalchemy.sql import select, literal
  35 from sqlalchemy.sql.expression import join
  36
  37 from xfeatures import XFeatures
  38 from groups import Groups
  39 from public import Public
  40
  41
  42 READ = 0
  43 WRITE = 1
  44
  45
  46 class Permissions(XFeatures, Groups, Public):
  47
  48     def __init__(self, **params):
  49         XFeatures.__init__(self, **params)
  50         Groups.__init__(self, **params)
  51         Public.__init__(self, **params)
  52
  53     def access_grant(self, path, access, members=()):
  54         """Grant members with access to path.
  55            Members can also be '*' (all),
  56            or some group specified as 'owner:group'."""
  57
  58         if not members:
  59             return
  60         feature = self.xfeature_create(path)
  61         if feature is None:
  62             return
  63         self.feature_setmany(feature, access, members)
  64
  65     def access_set(self, path, permissions):
  66         """Set permissions for path. The permissions dict
  67            maps 'read', 'write' keys to member lists."""
  68
  69         self.xfeature_destroy(path)
  70         self.access_grant(path, READ, permissions.get('read', []))
  71         self.access_grant(path, WRITE, permissions.get('write', []))
  72
  73     def access_clear(self, path):
  74         """Revoke access to path (both permissions and public)."""
  75
  76         self.xfeature_destroy(path)
  77         self.public_unset(path)
  78
  79     def access_check(self, path, access, member):
  80         """Return true if the member has this access to the path."""
  81
  82         if access == READ and self.public_check(path):
  83             return True
  84
  85         r = self.xfeature_inherit(path)
  86         if not r:
  87             return False
  88         fpath, feature = r
  89         members = self.feature_get(feature, access)
  90         if member in members or '*' in members:
  91             return True
  92         for owner, group in self.group_parents(member):
  93             if owner + ':' + group in members:
  94                 return True
  95         return False
  96
  97     def access_inherit(self, path):
  98         """Return the inherited or assigned (path, permissions) pair for path."""
  99
 100         r = self.xfeature_inherit(path)
 101         if not r:
 102             return (path, {})
 103         fpath, feature = r
 104         permissions = self.feature_dict(feature)
 105         if READ in permissions:
 106             permissions['read'] = permissions[READ]
 107             del(permissions[READ])
 108         if WRITE in permissions:
 109             permissions['write'] = permissions[WRITE]
 110             del(permissions[WRITE])
 111         return (fpath, permissions)
 112
 113     def access_list(self, path):
 114         """List all permission paths inherited by or inheriting from path."""
 115
 116         return [x[0] for x in self.xfeature_list(path) if x[0] != path]
 117
 118     def access_list_paths(self, member, prefix=None):
 119         """Return the list of paths granted to member."""
 120
 121         xfeatures_xfeaturevals =  self.xfeatures.join(self.xfeaturevals)
 122
 123         selectable = (self.groups.c.owner + ':' + self.groups.c.name)
 124         member_groups = select([selectable.label('value')],
 125             self.groups.c.member == member)
 126
 127         members = select([literal(member).label('value')])
 128         any = select([literal('*').label('value')])
 129
 130         inner_join = join(xfeatures_xfeaturevals,
 131                     union(member_groups, members, any),
 132                     self.xfeaturevals.c.value == extended_member_groups.c.value)
 133         s = select([self.xfeatures.c.path], from_obj=[inner_join]).distinct()
 134         if prefix:
 135             s = s.where(self.xfeatures.c.path.like(prefix + '%'))
 136         r = self.conn.execute(s)
 137         l = [row[0] for row in r.fetchall()]
 138         r.close()
 139         return l
 140
 141     def access_list_shared(self, prefix=''):
 142         """Return the list of shared paths."""
 143
 144         s = select([self.xfeatures.c.path],
 145             self.xfeatures.c.path.like(prefix + '%'))
 146         r = self.conn.execute(s)
 147         l = [row[0] for row in r.fetchall()]
 148         r.close()
 149         return l