Class: WAZ::Queues::Service

Inherits:
Object
  • Object
show all
Includes:
Storage::SharedKeyCoreService
Defined in:
lib/waz/queues/service.rb

Overview

This is internally used by the waz-queues part of the gem and it exposes the Windows Azure Queue API REST methods implementation. You can use this class to perform an specific operation that aren’t provided by the current API.

Instance Attribute Summary

Attributes included from Storage::SharedKeyCoreService

#access_key, #account_name, #base_url, #type_of_service, #use_devenv, #use_ssl

Instance Method Summary collapse

Methods included from Storage::SharedKeyCoreService

#canonicalize_headers, #canonicalize_message, #canonicalize_message20090919, #execute, #generate_request, #generate_request_uri, #generate_signature, #generate_signature20090919, #initialize

Instance Method Details

#clear_queue(queue_name) ⇒ Object

Marks every message on the given queue for deletion.



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# File 'lib/waz/queues/service.rb', line 101

def clear_queue(queue_name)
  execute :delete, "#{queue_name}/messages", {}, :x_ms_version => '2009-09-19'
end

#create_queue(queue_name, metadata = {}) ⇒ Object

Creates a queue on the current storage account. Throws WAZ::Queues::QueueAlreadyExists when existing metadata and given metadata differ.



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# File 'lib/waz/queues/service.rb', line 33

def create_queue(queue_name, metadata = {})
  execute(:put, queue_name, nil, metadata.merge!(:x_ms_version => '2009-09-19'))
end

#delete_message(queue_name, message_id, pop_receipt) ⇒ Object

Deletes the given message from the queue, correlating the operation with the pop_receipt in order to avoid eventually inconsistent scenarios.



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# File 'lib/waz/queues/service.rb', line 96

def delete_message(queue_name, message_id, pop_receipt)
  execute :delete, "#{queue_name}/messages/#{message_id}", { :pop_receipt => pop_receipt }
end

#delete_queue(queue_name) ⇒ Object

Deletes the given queue from the current storage account.



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# File 'lib/waz/queues/service.rb', line 38

def delete_queue(queue_name)
  execute(:delete, queue_name, {}, {:x_ms_version => '2009-09-19'})
end

#enqueue(queue_name, message_payload, ttl = 604800) ⇒ Object

Enqueues a message on the current queue.

ttl Specifies the time-to-live interval for the message, in seconds. The maximum time-to-live allowed is 7 days. If this parameter is omitted, the default time-to-live is 7 days.



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# File 'lib/waz/queues/service.rb', line 56

def enqueue(queue_name, message_payload, ttl = 604800)
  payload = "<?xml version=\"1.0\" encoding=\"utf-8\"?><QueueMessage><MessageText>#{message_payload}</MessageText></QueueMessage>"
  execute(:post, "#{queue_name}/messages", { :messagettl => ttl }, { 'Content-Type' => 'application/xml', :x_ms_version => "2009-09-19"}, payload)
end

#get_messages(queue_name, options = {}) ⇒ Object

Locks N messages (1 default) from the given queue.

:num_of_messages option specifies the max number of messages to get (maximum 32)

:visibility_timeout option specifies the timeout of the message locking in seconds (max two hours)

Raises:



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# File 'lib/waz/queues/service.rb', line 66

def get_messages(queue_name, options = {})
  raise WAZ::Queues::OptionOutOfRange, {:name => :num_of_messages, :min => 1, :max => 32} if (options.keys.include?(:num_of_messages) && (options[:num_of_messages].to_i < 1 || options[:num_of_messages].to_i > 32))
  raise WAZ::Queues::OptionOutOfRange, {:name => :visibility_timeout, :min => 1, :max => 7200} if (options.keys.include?(:visibility_timeout) && (options[:visibility_timeout].to_i < 1 || options[:visibility_timeout].to_i > 7200))
  content = execute(:get, "#{queue_name}/messages", options, {:x_ms_version => "2009-09-19"})
  doc = REXML::Document.new(content)
  messages = []
  REXML::XPath.each(doc, '//QueueMessage/') do |item|
    message = { :message_id => REXML::XPath.first(item, "MessageId").text,
                :message_text => REXML::XPath.first(item, "MessageText").text,
                :dequeue_count => REXML::XPath.first(item, "DequeueCount").nil? ? nil : REXML::XPath.first(item, "DequeueCount").text.to_i,
                :expiration_time => Time.httpdate(REXML::XPath.first(item, "ExpirationTime").text),
                :insertion_time => Time.httpdate(REXML::XPath.first(item, "InsertionTime").text) }

    # This are only valid when peek-locking messages
    message[:pop_receipt] = REXML::XPath.first(item, "PopReceipt").text unless REXML::XPath.first(item, "PopReceipt").nil?
    message[:time_next_visible] = Time.httpdate(REXML::XPath.first(item, "TimeNextVisible").text) unless REXML::XPath.first(item, "TimeNextVisible").nil?
    messages << message
  end
  return messages
end

#get_queue_metadata(queue_name) ⇒ Object

Gets the given queue metadata.



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# File 'lib/waz/queues/service.rb', line 43

def get_queue_metadata(queue_name)
  execute(:head, queue_name, { :comp => 'metadata'}, :x_ms_version => '2009-09-19').headers
end

#list_queues(options = {}) ⇒ Object

Lists the queues on the given storage account.

When the options :include => ‘metadata’ is passed it returns the corresponding metadata for each queue on the listing.



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# File 'lib/waz/queues/service.rb', line 12

def list_queues(options ={})
  content = execute(:get, nil, { :comp => 'list' }.merge!(options), { :x_ms_version => "2009-09-19" })
  doc = REXML::Document.new(content)
  queues = []
  
  REXML::XPath.each(doc, '//Queue/') do |item|
    metadata = {}
    
    item.elements['Metadata'].elements.each do |element|
      metadata.merge!(element.name.gsub(/-/, '_').downcase.to_sym => element.text)
    end unless item.elements['Metadata'].nil?
    
    queues << { :name => REXML::XPath.first(item, "Name").text,
                :url => REXML::XPath.first(item, "Url").text,
                :metadata => metadata}
  end
  return queues
end

#peek(queue_name, options = {}) ⇒ Object

Peeks N messages (default 1) from the given queue.

Implementation is the same of get_messages but differs on an additional parameter called :peek_only.



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# File 'lib/waz/queues/service.rb', line 90

def peek(queue_name, options = {})
  return get_messages(queue_name, {:peek_only => true}.merge(options))
end

#set_queue_metadata(queue_name, metadata = {}) ⇒ Object

Sets the given queue metadata.



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# File 'lib/waz/queues/service.rb', line 48

def set_queue_metadata(queue_name, metadata = {})
  execute(:put, queue_name, { :comp => 'metadata' }, metadata.merge!(:x_ms_version => '2009-09-19'))
end