Rails/Ruby Parse AWS SNS Topic Notification Data - ruby-on-rails

Question

There is this rails app which I created to accept SNS topic notification data. In summery SNS notification is generated on completion of a elastic transcoder job. So the rails app simply accept the incoming post request from AWS SNS service and All I need to parse this data. What doesn't work for me is, I'm trying to retrieve the Message => jobId but I can't figure out how. Appreciate any help.
def sns_transcode_completed
amz_message_type = request.headers['x-amz-sns-message-type']
amz_sns_topic = request.headers['x-amz-sns-topic-arn']
if !amz_sns_topic.nil? &&
amz_sns_topic.to_s.downcase == 'arn:aws:sns:us-east-1:XXXXXXXXXX:MyApp_transcode_completed'
request_body = JSON.parse(request.body.read, {:symbolize_names => true})
notification = Hashie::Mash.new(request_body)
if amz_message_type.to_s.downcase == 'subscriptionconfirmation'
subscribe_url = request_body['SubscribeURL']
if !subscribe_url.to_s.empty? && !subscribe_url.nil?
subscribe_confirm = HTTParty.get subscribe_url
puts subscribe_confirm
puts subscribe_url
end
end
if amz_message_type.to_s.downcase == 'notification'
puts "--------------------------"
puts notification.inspect # See output 1
puts "--------------------------"
puts notification.MessageId # This works I can get the MessageId
puts "--------------------------"
puts notification.Message => # From here I need to get the jobId, but it comes as a String? See output 2
puts "--------------------------"
end
end
render :nothing => true, :status => 200, :content_type => 'text/html'
end
Output 1
#<Hashie::Mash Message="{\n \"state\" : \"COMPLETED\",\n \"version\" : \"2012-09-25\",\n \"jobId\" : \"1440122777052-XXXXXX\",\n \"pipelineId\" :
\"1432361831290-XXXXX\",\n \"input\" : {\n \"key\" : \"web-b796ab20-297c-0133-4ccf-378cf690e3b1.mp3\"\n },\n \"outputKeyPrefix\" :
\"hlsv4/246-21632840-29d7-0133-1d8e-XXXXXXXX/\",\n \"outputs\" : [ {\n \"id\" : \"1\",\n \"presetId\" : \"1351620000001-200071\",\n \"key\" : \"hls_64k\",\n
\"segmentDuration\" : 10.0,\n \"status\" : \"Complete\",\n \"duration\" : 60\n } ],\n \"playlists\" : [ {\n \"name\" : \"index\",\n \"format\" : \"HLSv4\",\n
\"outputKeys\" : [ \"hls_64k\" ],\n \"status\" : \"Complete\"\n } ]\n}" MessageId="2d26f6d0-1715-5edb-af39-b8809eff521f" Signature="XXXXXX" SignatureVersion="1"
SigningCertURL="https://sns.us-east-1.amazonaws.com/SimpleNotificationService-d6d679a1d18e95c2f9ffcf11fXXXXXXX.pem" Subject="Amazon Elastic Transcoder has
finished transcoding job 1440122777052-XXXXXX." Timestamp="2015-08-21T02:06:34.523Z" TopicArn="arn:aws:sns:us-east-1:005550634774:MyApp_transcode_completed"
Type="Notification"
UnsubscribeURL="https://sns.us-east-1.amazonaws.com/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:us-east-1:005550634774:MyApp_transcode_completed:8c0e48fe-c34
9-4185- bb94-XXXXXXXXXX">
Output 2
{
"state": "COMPLETED",
"version": "2012-09-25",
"jobId": "1440122777052-XXXXX",
"pipelineId": "1432361831290-XXXXXX",
"input": {
"key": "web-b796ab20-297c-0133-4ccf-378cf690e3b1.mp3"
},
"outputKeyPrefix": "hlsv4/246-21632840-29d7-0133-1d8e-35ebbdecd855/",
"outputs": [
{
"id": "1",
"presetId": "1351620000001-200071",
"key": "hls_64k",
"segmentDuration": 10,
"status": "Complete",
"duration": 60
}
],
"playlists": [
{
"name": "index",
"format": "HLSv4",
"outputKeys": [
"hls_64k"
],
"status": "Complete"
}
]
}

Answer 1

I was having the same issue and I ended up ditching Hashie.(It's really not needed aside from being able to use dot notation in this case.) I did still have to double parse (due to the string returned when you dig out the message). Once I grabbed that, the object I wanted to get at was in an Array so I used the dig method to pull out the object and then access the data I needed.
def sns_endpoint
notification = JSON.parse(request.raw_post, {:symbolize_names => true})
case notification[:Type]
when "SubscriptionConfirmation"
confirm(notification[:TopicArn], notification[:Token])
when "Notification"
message_data = JSON.parse(notification[:Message])
thing_you_are_trying_to_get = message_data["Records"].dig(0)["s3"]...etc...(access the data you need here.)
else
Rails.logger.error "Unknown notification type #{notification[:Type]}"
end
render body: nil
end

Answer 2

I got this working parsing the notification.Message value again. I wish if there is a better way than this.
parsed_message = JSON.parse(notification.Message, {:symbolize_names => true})
puts parsed_message.inspect
puts "--------------------------"
puts parsed_message[:jobId]