= RCAP - Common Alerting Protocol for Ruby == Overview The Common Alerting Protocol is a lightweight standard to facilitate the distribution of alerting data. RCAP is an implementation of the CAP in Ruby. It allows for the creation of RCAP messages from Ruby applications and the parsing of external messages. RCAP currently supports only CAP Version 1.1. == Version 0.4 == Dependencies RCAP depends on the following gems * {Assistance}[http://assistance.rubyforge.org] * {UUIDTools}[http://uuidtools.rubyforge.org] * {JSON}[http://json.rubyforge.org] RCAP uses the REXML API, included in Ruby, to parse and generate XML. == Installation RCAP is distributed as a Ruby gem and is available from {Gemcutter}[http://gemcutter.org]. If you have Gemcutter set as a source of your gems then RCAP can be installed from the command line gem install rcap The gem is also available for download and manual installtion at http://www.aimred.com/gems . == Web resources * The RCAP project page can be found at http://www.aimred.com/projects/rcap * The RCAP API docs can be fount at http://www.aimred.com/projects/rcap/api * A public git repository can be found at git://github.com/farrel/RCAP.git == Usage To include RCAP into your application add the following require require 'rcap' All RCAP classes reside in the RCAP namespace but including the RCAP module makes the classes available at the top level without the RCAP prefix. alert = RCAP::Alert.new(... include RCAP # Include RCAP module into namespace alert = Alert.new(... === Creating an Alert alert = Alert.new( :sender => 'cape_town_disaster_relief@capetown.municipal.za', :status => Alert::STATUS_ACTUAL, :msg_type => Alert::MSG_TYPE_ALERT, :scope => Alert::SCOPE_PUBLIC, :infos => Info.new( :event => 'Liquid Petroleoum Tanker Fire', :language => 'en-ZA', :categories => [ Info::CATEGORY_TRANSPORT, Info::CATEGORY_FIRE ], :urgency => Info::URGENCY_IMMEDIATE, :severity => Info::SEVERITY_SEVERE, :certainty => Info::CERTAINTY_OBSERVED, :headline => 'LIQUID PETROLEOUM TANKER FIRE ON N2 INCOMING FREEWAY', :description => 'A liquid petroleoum tanker has caught fire on the N2 incoming freeway 1km after the R300 interchange. Municipal fire fighting crews have been dispatched. Traffic control officers are on the scene and have diverted traffic onto alternate routes.' )) # Accessing attributes puts alert.status # Print out "Actual" puts alert.infos[0].language # Print out "en-ZA" puts alert.infos[0].categories.join( ' ' ) # Print out "Transport Fire" === Exporting an Alert ==== To XML Using the alert message created above puts alert.to_xml # Print out CAP XML message Will print the following CAP XML 494207a7-f86b-4060-8318-a4b2a3ce565e cape_town_disaster_relief@capetown.municipal.za 2009-10-26T21:04:51+02:00 Actual Alert Public en-ZA Transport Fire Liquid Petroleoum Tanker Fire Immediate Severe Observed LIQUID PETROLEOUM TANKER FIRE ON N2 INCOMING FREEWAY A liquid petroleoum tanker has caught fire on the N2 incoming freeway 1km after the R300 interchange. Municipal fire fighting crews have been dispatched. Traffic control officers are on the scene and have diverted traffic onto alternate routes. ==== To YAML YAML is a plain text serialization format designed to be easily readable and editable by both human and machine. RCAP has custom YAML generation and parsing methods to produce a YAML document that is as human friednly as possible. The following code alert.to_yaml will produce the following YAML document --- Identifier: 2a1ba96d-16e4-4f52-85ea-0258c1440bd5 Sender: cape_town_disaster_relief@capetown.municipal.za Sent: 2009-11-19T02:41:29+02:00 Status: Actual Message Type: Alert Scope: Public Information: - Language: en-ZA Categories: [Transport, Fire] Event: Liquid Petroleoum Tanker Fire Urgency: Immediate Severity: Severe Certainty: Observed Headline: LIQUID PETROLEOUM TANKER FIRE ON N2 INCOMING FREEWAY Description: |- A liquid petroleoum tanker has caught fire on the N2 incoming freeway 1km after the R300 interchange. Municipal fire fighting crews have been dispatched. Traffic control officers are on the scene and have diverted traffic onto alternate routes. Note: If you use Ruby 1.8 the order of the attributes is jumbled due to hashes being unorderd (Ruby 1.9 implements ordered hashes). This does not affect the ability to parse documents generated from RCAP::Alert#to_yaml, it just makes things the output slightly messy. === To JSON JSON(JavaScript Object Notation) is a text serialization format that can be easily loaded in a JavaScript environment. alert.to_json will produce the following JSON string {"identifier":"0eb97e40-195b-437b-9a01-55fe89691def", "sender":"cape_town_disaster_relief@capetown.municipal.za", "sent":"2011-03-04T15:58:01+02:00", "status":"Actual", "msg_type":"Alert", "scope":"Public", "infos":[ {"language":"en-ZA", "categories":["Transport","Fire"], "event":"Liquid Petroleoum Tanker Fire", "urgency":"Immediate", "severity":"Severe", "certainty":"Observed", "headline":"LIQUID PETROLEOUM TANKER FIRE ON N2 INCOMING FREEWAY", "description":"A liquid petroleoum tanker has caught fire on the N2 incoming freeway 1km after the R300 interchange. Municipal fire fighting crews have been dispatched. Traffic control officers are on the scene and have diverted traffic onto \nalternate routes."}]} === Parsing an Alert From An External Source ==== From XML RCAP allows for the parsing of a CAP XML string alert = RCAP::Alert.from_xml( xml_string ) Currently RCAP only supports version 1.1 of the CAP standard and the parser is as strict as possible when parsing data. ==== From YAML Alert messgaes can be read in from text files containing data formatted in YAML as generated by Alert#to_yaml. alert = RCAP::Alert.from_yaml( yaml_string ) ==== From JSON An Alert can also be initialised from a JSON string produced by Alert#to_json alert = RCAP::Alert.from_json( json_string ) === Validating an alert The RCAP API aims to codify as many of the rules of the CAP XML format into validation rules that can be checked using the Assistance API. The following Info object has two attributes ('severity' and 'certainty') set to incorrect values. info = Info.new( :event => 'Liquid Petroleoum Tanker Fire', :language => 'en-ZA', :categories => [ Info::CATEGORY_TRANSPORT, Info::CATEGORY_FIRE ], :urgency => Info::URGENCY_IMMEDIATE, :severity => nil, # Severity is not assigned :certainty => 'Unknown Certainty' ) # Certainty is assigned in incorrect value puts "Is info valid: #{ info.valid? }" info.errors.full_messages.each{ |message| puts "Error: #{ message }" } Will produce the folling output: Is info valid: false Error: severity is not present Error: certainty can only be assigned the following values: Observed, Likely, Possible, Unlikely, Unknown All RCAP classes include the Validation module. A full spec suite using {RSpec}[http://www.rspec.info] was used to test the validations and currently numbers over 250 tests. === DateTime and Time It is highly recommended that when dealing with date and time fields (onset, expires etc) that the DateTime class is used to ensure the correct formatting of dates. The Time class can be used when generating a CAP alert XML message however any CAP alert that is parsed from an external XML source will use DateTime by default. == Authors Farrel Lifson - farrel.lifson@aimred.com == License RCAP is released under the BSD License. == Copyright 2009-2010 Aimred CC