Class: Heroic::SNS::Message

Inherits:
Object
  • Object
show all
Defined in:
lib/heroic/sns/message.rb

Overview

Encapsulates an SNS message. See: docs.aws.amazon.com/sns/latest/gsg/json-formats.html

Instance Method Summary collapse

Constructor Details

#initialize(json) ⇒ Message

Returns a new instance of Message.



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# File 'lib/heroic/sns/message.rb', line 24

def initialize(json)
  @msg = ::JSON.parse(json)
rescue JSON::ParserError => e
  raise Error.new("failed to parse message as JSON: #{e.message}")
end

Instance Method Details

#==(other_message) ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 83

def ==(other_message)
  @msg == other_message.instance_variable_get(:@msg)
end

#body ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 65

def body
  @msg['Message']
end

#hash ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 87

def hash
  @msg.hash
end

#id ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 38

def id
  @msg['MessageId']
end

#signature ⇒ Object

The message signature data, Base-64 decoded.



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# File 'lib/heroic/sns/message.rb', line 56

def signature
  Base64::decode64(@msg['Signature'])
end

#signature_version ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 47

def signature_version
  @msg['SignatureVersion']
end

#signing_cert_url ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 51

def signing_cert_url
  @msg['SigningCertURL']
end

#subject ⇒ Object

The message may not have a subject.



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# File 'lib/heroic/sns/message.rb', line 61

def subject
  @msg['Subject']
end

#subscribe_url ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 69

def subscribe_url
  @msg['SubscribeURL']
end

#timestamp ⇒ Object

The timestamp as a Time object.



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# File 'lib/heroic/sns/message.rb', line 43

def timestamp
  Time.xmlschema(@msg['Timestamp'])
end

#to_json ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 99

def to_json
  @msg.to_json
end

#to_s ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 91

def to_s
  string = "<SNSMessage:\n"
  @msg.each do |k,v|
    string << sprintf("  %s: %s\n", k, v.inspect)
  end
  string << ">"
end

#token ⇒ Object

The token is used to confirm subscriptions via the SNS API. If you visit the :subscribe_url, you can ignore this field.



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# File 'lib/heroic/sns/message.rb', line 79

def token
  @msg['Token']
end

#topic_arn ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 34

def topic_arn
  @msg['TopicArn']
end

#type ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 30

def type
  @msg['Type']
end

#unsubscribe_url ⇒ Object 



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# File 'lib/heroic/sns/message.rb', line 73

def unsubscribe_url
  @msg['UnsubscribeURL']
end

#verify! ⇒ Object

Verifies the message signature. Raises an exception if it is not valid. See: docs.aws.amazon.com/sns/latest/gsg/SendMessageToHttp.verify.signature.html

Raises:

  • (Errow) 


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# File 'lib/heroic/sns/message.rb', line 105

def verify!
  age = Time.now - timestamp
  raise Errow.new("timestamp is in the future", self) if age < 0
  raise Error.new("timestamp is too old", self) if age > MAXIMUM_ALLOWED_AGE
  if signature_version != '1'
    raise Error.new("unknown signature version: #{signature_version}", self)
  end
  if signing_cert_url !~ %r[^https://.*amazonaws\.com/]
    raise Error.new("signing certificate is not from amazonaws.com", self)
  end
  text = string_to_sign # will warn of invalid Type
  cert = CERTIFICATE_CACHE[signing_cert_url]
  digest = OpenSSL::Digest::SHA1.new
  unless cert.public_key.verify(digest, signature, text)
    raise Error.new("message signature is invalid", self)
  end
end