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comparison planemo/lib/python3.7/site-packages/boto/sdb/item.py @ 0:d30785e31577 draft

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"planemo upload commit 6eee67778febed82ddd413c3ca40b3183a3898f1"
author guerler
date Fri, 31 Jul 2020 00:18:57 -0400
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1 # Copyright (c) 2006,2007 Mitch Garnaat http://garnaat.org/
2 #
3 # Permission is hereby granted, free of charge, to any person obtaining a
4 # copy of this software and associated documentation files (the
5 # "Software"), to deal in the Software without restriction, including
6 # without limitation the rights to use, copy, modify, merge, publish, dis-
7 # tribute, sublicense, and/or sell copies of the Software, and to permit
8 # persons to whom the Software is furnished to do so, subject to the fol-
9 # lowing conditions:
10 #
11 # The above copyright notice and this permission notice shall be included
12 # in all copies or substantial portions of the Software.
13 #
14 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
15 # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
16 # ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
17 # SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
18 # WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
20 # IN THE SOFTWARE.
21
22 import base64
23
24 class Item(dict):
25 """
26 A ``dict`` sub-class that serves as an object representation of a
27 SimpleDB item. An item in SDB is similar to a row in a relational
28 database. Items belong to a :py:class:`Domain <boto.sdb.domain.Domain>`,
29 which is similar to a table in a relational database.
30
31 The keys on instances of this object correspond to attributes that are
32 stored on the SDB item.
33
34 .. tip:: While it is possible to instantiate this class directly, you may
35 want to use the convenience methods on :py:class:`boto.sdb.domain.Domain`
36 for that purpose. For example, :py:meth:`boto.sdb.domain.Domain.get_item`.
37 """
38 def __init__(self, domain, name='', active=False):
39 """
40 :type domain: :py:class:`boto.sdb.domain.Domain`
41 :param domain: The domain that this item belongs to.
42
43 :param str name: The name of this item. This name will be used when
44 querying for items using methods like
45 :py:meth:`boto.sdb.domain.Domain.get_item`
46 """
47 dict.__init__(self)
48 self.domain = domain
49 self.name = name
50 self.active = active
51 self.request_id = None
52 self.encoding = None
53 self.in_attribute = False
54 self.converter = self.domain.connection.converter
55
56 def startElement(self, name, attrs, connection):
57 if name == 'Attribute':
58 self.in_attribute = True
59 self.encoding = attrs.get('encoding', None)
60 return None
61
62 def decode_value(self, value):
63 if self.encoding == 'base64':
64 self.encoding = None
65 return base64.decodestring(value)
66 else:
67 return value
68
69 def endElement(self, name, value, connection):
70 if name == 'ItemName':
71 self.name = self.decode_value(value)
72 elif name == 'Name':
73 if self.in_attribute:
74 self.last_key = self.decode_value(value)
75 else:
76 self.name = self.decode_value(value)
77 elif name == 'Value':
78 if self.last_key in self:
79 if not isinstance(self[self.last_key], list):
80 self[self.last_key] = [self[self.last_key]]
81 value = self.decode_value(value)
82 if self.converter:
83 value = self.converter.decode(value)
84 self[self.last_key].append(value)
85 else:
86 value = self.decode_value(value)
87 if self.converter:
88 value = self.converter.decode(value)
89 self[self.last_key] = value
90 elif name == 'BoxUsage':
91 try:
92 connection.box_usage += float(value)
93 except:
94 pass
95 elif name == 'RequestId':
96 self.request_id = value
97 elif name == 'Attribute':
98 self.in_attribute = False
99 else:
100 setattr(self, name, value)
101
102 def load(self):
103 """
104 Loads or re-loads this item's attributes from SDB.
105
106 .. warning::
107 If you have changed attribute values on an Item instance,
108 this method will over-write the values if they are different in
109 SDB. For any local attributes that don't yet exist in SDB,
110 they will be safe.
111 """
112 self.domain.get_attributes(self.name, item=self)
113
114 def save(self, replace=True):
115 """
116 Saves this item to SDB.
117
118 :param bool replace: If ``True``, delete any attributes on the remote
119 SDB item that have a ``None`` value on this object.
120 """
121 self.domain.put_attributes(self.name, self, replace)
122 # Delete any attributes set to "None"
123 if replace:
124 del_attrs = []
125 for name in self:
126 if self[name] is None:
127 del_attrs.append(name)
128 if len(del_attrs) > 0:
129 self.domain.delete_attributes(self.name, del_attrs)
130
131 def add_value(self, key, value):
132 """
133 Helps set or add to attributes on this item. If you are adding a new
134 attribute that has yet to be set, it will simply create an attribute
135 named ``key`` with your given ``value`` as its value. If you are
136 adding a value to an existing attribute, this method will convert the
137 attribute to a list (if it isn't already) and append your new value
138 to said list.
139
140 For clarification, consider the following interactive session:
141
142 .. code-block:: python
143
144 >>> item = some_domain.get_item('some_item')
145 >>> item.has_key('some_attr')
146 False
147 >>> item.add_value('some_attr', 1)
148 >>> item['some_attr']
149 1
150 >>> item.add_value('some_attr', 2)
151 >>> item['some_attr']
152 [1, 2]
153
154 :param str key: The attribute to add a value to.
155 :param object value: The value to set or append to the attribute.
156 """
157 if key in self:
158 # We already have this key on the item.
159 if not isinstance(self[key], list):
160 # The key isn't already a list, take its current value and
161 # convert it to a list with the only member being the
162 # current value.
163 self[key] = [self[key]]
164 # Add the new value to the list.
165 self[key].append(value)
166 else:
167 # This is a new attribute, just set it.
168 self[key] = value
169
170 def delete(self):
171 """
172 Deletes this item in SDB.
173
174 .. note:: This local Python object remains in its current state
175 after deletion, this only deletes the remote item in SDB.
176 """
177 self.domain.delete_item(self)