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
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
# Copyright 2011-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
module AWS
class SQS
# Represents a message received from an Amazon SQS Queue.
class ReceivedMessage
include Core::Model
# @return [Queue] The queue from which this message was
# received.
attr_reader :queue
# @return [String] The ID of the message.
attr_reader :id
# @return [String] A string associated with this specific
# instance of receiving the message.
attr_reader :handle
# @return [String] The message's contents.
attr_reader :body
# @return [String] An MD5 digest of the message body.
attr_reader :md5
# @return [String] The request ID.
attr_reader :request_id
# @api private
attr_reader :attributes
# @return [String] The message attributes attached to the message.
attr_reader :message_attributes
# @api private
ATTRIBUTE_ALIASES = {
:sent_at => :sent_timestamp,
:receive_count => :approximate_receive_count,
:first_received_at => :approximate_first_receive_timestamp
}
# @api private
def initialize(queue, id, handle, opts = {})
@queue = queue
@id = id
@handle = handle
@body = opts[:body]
@md5 = opts[:md5]
@request_id = opts[:request_id]
@attributes = opts[:attributes] || {}
@message_attributes = opts[:message_attributes] || {}
super
end
# When SNS publishes messages to SQS queues the message body is
# formatted as a json message and then base 64 encoded.
#
# @example
#
# sns_msg = message.as_sns_message
#
# sns_msg.topic
# #=> <AWS::SNS::Topic ...>
#
# sns_msg.to_h.inspect
# #=> { :body => '...', :topic_arn => ... }
#
# @return [ReceivedSNSMessage]
def as_sns_message
ReceivedSNSMessage.new(body, :config => config)
end
# Deletes the message from the queue. Even if the message is
# locked by another reader due to the visibility timeout
# setting, it is still deleted from the queue. If you leave a
# message in the queue for more than 4 days, SQS automatically
# deletes it.
#
# If you use {Queue#poll} or {Queue#receive_message} in block
# form, the messages you receive will be deleted automatically
# unless an exception occurs while you are processing them.
# You can still use this method if you want to delete a
# message early and then continue processing it.
#
# @note It is possible you will receive a message even after
# you have deleted it. This might happen on rare occasions
# if one of the servers storing a copy of the message is
# unavailable when you request to delete the message. The
# copy remains on the server and might be returned to you
# again on a subsequent receive request. You should create
# your system to be idempotent so that receiving a
# particular message more than once is not a problem.
#
# @return [nil]
def delete
client.delete_message(
:queue_url => queue.url,
:receipt_handle => handle)
nil
end
# Changes the visibility timeout of a specified message in a
# queue to a new value. The maximum allowed timeout value you
# can set the value to is 12 hours. This means you can't
# extend the timeout of a message in an existing queue to more
# than a total visibility timeout of 12 hours. (For more
# information visibility timeout, see
# [Visibility Timeout](http://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/IntroductionArticle.html#AboutVT)
# in the Amazon SQS Developer Guide.)
#
# For example, let's say the timeout for the queue is 30
# seconds, and you receive a message. Once you're 20 seconds
# into the timeout for that message (i.e., you have 10 seconds
# left), you extend it by 60 seconds by calling this method
# with `timeout` set to 60 seconds. You have then changed the
# remaining visibility timeout from 10 seconds to 60 seconds.
#
# @note If you attempt to set the timeout to an amount more
# than the maximum time left, Amazon SQS returns an
# error. It will not automatically recalculate and increase
# the timeout to the maximum time remaining.
#
# @note Unlike with a queue, when you change the visibility
# timeout for a specific message, that timeout value is
# applied immediately but is not saved in memory for that
# message. If you don't delete a message after it is
# received, the visibility timeout for the message the next
# time it is received reverts to the original timeout value,
# not the value you set with this method.
#
# @return Returns the timeout argument as passed.
#
def visibility_timeout=(timeout)
client.change_message_visibility(
:queue_url => queue.url,
:receipt_handle => handle,
:visibility_timeout => timeout
)
timeout
end
# @return [String] The AWS account number (or the IP address,
# if anonymous access is allowed) of the sender.
def sender_id
attributes["SenderId"]
end
# @return [Time] The time when the message was sent.
def sent_timestamp
@sent_at ||=
(timestamp = attributes["SentTimestamp"] and
Time.at(timestamp.to_i / 1000.0)) || nil
rescue RangeError => e
p [timestamp, timestamp.to_i]
end
alias_method :sent_at, :sent_timestamp
# @return [Integer] The number of times a message has been
# received but not deleted.
def approximate_receive_count
(count = attributes["ApproximateReceiveCount"] and
count.to_i) or nil
end
alias_method :receive_count, :approximate_receive_count
# @return [Time] The time when the message was first received.
def approximate_first_receive_timestamp
@received_at ||=
(timestamp = attributes["ApproximateFirstReceiveTimestamp"] and
Time.at(timestamp.to_i / 1000.0)) || nil
end
alias_method :first_received_at, :approximate_first_receive_timestamp
end
end
end
|
