1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TypeFamilies #-}
-----------------------------------------------------------------------------
-- |
-- Module : Aws.DynamoDb.Commands.GetItem
-- Copyright : Soostone Inc
-- License : BSD3
--
-- Maintainer : Ozgun Ataman <ozgun.ataman@soostone.com>
-- Stability : experimental
--
--
----------------------------------------------------------------------------
module Aws.DynamoDb.Commands.GetItem where
-------------------------------------------------------------------------------
import Control.Applicative
import Data.Aeson
import Data.Default
import qualified Data.Text as T
import Prelude
-------------------------------------------------------------------------------
import Aws.Core
import Aws.DynamoDb.Core
-------------------------------------------------------------------------------
-- | A GetItem query that fetches a specific object from DDB.
--
-- See: @http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/API_GetItem.html@
data GetItem = GetItem {
giTableName :: T.Text
, giKey :: PrimaryKey
, giAttrs :: Maybe [T.Text]
-- ^ Attributes to get. 'Nothing' grabs everything.
, giConsistent :: Bool
-- ^ Whether to issue a consistent read.
, giRetCons :: ReturnConsumption
-- ^ Whether to return consumption stats.
} deriving (Eq,Show,Read,Ord)
-------------------------------------------------------------------------------
-- | Construct a minimal 'GetItem' request.
getItem
:: T.Text -- ^ Table name
-> PrimaryKey -- ^ Primary key
-> GetItem
getItem tn k = GetItem tn k Nothing False def
-- | Response to a 'GetItem' query.
data GetItemResponse = GetItemResponse {
girItem :: Maybe Item
, girConsumed :: Maybe ConsumedCapacity
} deriving (Eq,Show,Read,Ord)
instance Transaction GetItem GetItemResponse
instance ToJSON GetItem where
toJSON GetItem{..} = object $
maybe [] (return . ("AttributesToGet" .=)) giAttrs ++
[ "TableName" .= giTableName
, "Key" .= giKey
, "ConsistentRead" .= giConsistent
, "ReturnConsumedCapacity" .= giRetCons
]
instance SignQuery GetItem where
type ServiceConfiguration GetItem = DdbConfiguration
signQuery gi = ddbSignQuery "GetItem" gi
instance FromJSON GetItemResponse where
parseJSON (Object v) = GetItemResponse
<$> v .:? "Item"
<*> v .:? "ConsumedCapacity"
parseJSON _ = fail "GetItemResponse must be an object."
instance ResponseConsumer r GetItemResponse where
type ResponseMetadata GetItemResponse = DdbResponse
responseConsumer _ _ ref resp = ddbResponseConsumer ref resp
instance AsMemoryResponse GetItemResponse where
type MemoryResponse GetItemResponse = GetItemResponse
loadToMemory = return
|
