module Agents
class DataOutputAgent < Agent
cannot_be_scheduled!
description do
<<-MD
The Agent outputs received events as either RSS or JSON. Use it to output a public or private stream of Huginn data.
This Agent will output data at:
`https://#{ENV['DOMAIN']}#{Rails.application.routes.url_helpers.web_requests_path(agent_id: ':id', user_id: user_id, secret: ':secret', format: :xml)}`
where `:secret` is one of the allowed secrets specified in your options and the extension can be `xml` or `json`.
You can setup multiple secrets so that you can individually authorize external systems to
access your Huginn data.
Options:
* `secrets` - An array of tokens that the requestor must provide for light-weight authentication.
* `expected_receive_period_in_days` - How often you expect data to be received by this Agent from other Agents.
* `template` - A JSON object representing a mapping between item output keys and incoming event values. Use [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) to format the values. Values of the `link`, `title`, `description` and `icon` keys will be put into the \\<channel\\> section of RSS output. The `item` key will be repeated for every Event. The `pubDate` key for each item will have the creation time of the Event unless given.
* `events_to_show` - The number of events to output in RSS or JSON. (default: `40`)
* `ttl` - A value for the \\<ttl\\> element in RSS output. (default: `60`)
If you'd like to output RSS tags with attributes, such as `enclosure`, use something like the following in your `template`:
"enclosure": {
"_attributes": {
"url": "{{media_url}}",
"length": "1234456789",
"type": "audio/mpeg"
}
},
"another_tag": {
"_attributes": {
"key": "value",
"another_key": "another_value"
},
"_contents": "tag contents (can be an object for nesting)"
}
# Liquid Templating
In Liquid templating, the following variable is available:
* `events`: An array of events being output, sorted in descending order up to `events_to_show` in number. For example, if source events contain a site title in the `site_title` key, you can refer to it in `template.title` by putting `{{events.first.site_title}}`.
MD
end
def default_options
{
"secrets" => ["a-secret-key"],
"expected_receive_period_in_days" => 2,
"template" => {
"title" => "XKCD comics as a feed",
"description" => "This is a feed of recent XKCD comics, generated by Huginn",
"item" => {
"title" => "{{title}}",
"description" => "Secret hovertext: {{hovertext}}",
"link" => "{{url}}"
}
}
}
end
def working?
last_receive_at && last_receive_at > options['expected_receive_period_in_days'].to_i.days.ago && !recent_error_logs?
end
def validate_options
if options['secrets'].is_a?(Array) && options['secrets'].length > 0
options['secrets'].each do |secret|
case secret
when %r{[/.]}
errors.add(:base, "secret may not contain a slash or dot")
when String
else
errors.add(:base, "secret must be a string")
end
end
else
errors.add(:base, "Please specify one or more secrets for 'authenticating' incoming feed requests")
end
unless options['expected_receive_period_in_days'].present? && options['expected_receive_period_in_days'].to_i > 0
errors.add(:base, "Please provide 'expected_receive_period_in_days' to indicate how many days can pass before this Agent is considered to be not working")
end
unless options['template'].present? && options['template']['item'].present? && options['template']['item'].is_a?(Hash)
errors.add(:base, "Please provide template and template.item")
end
end
def events_to_show
(interpolated['events_to_show'].presence || 40).to_i
end
def feed_ttl
(interpolated['ttl'].presence || 60).to_i
end
def feed_title
interpolated['template']['title'].presence || "#{name} Event Feed"
end
def feed_link
interpolated['template']['link'].presence || "https://#{ENV['DOMAIN']}"
end
def feed_url(options = {})
feed_link + Rails.application.routes.url_helpers.
web_requests_path(agent_id: id || ':id',
user_id: user_id,
secret: options[:secret],
format: options[:format])
end
def feed_icon
interpolated['template']['icon'].presence || feed_link + '/favicon.ico'
end
def feed_description
interpolated['template']['description'].presence || "A feed of Events received by the '#{name}' Huginn Agent"
end
def receive_web_request(params, method, format)
unless interpolated['secrets'].include?(params['secret'])
if format =~ /json/
return [{ error: "Not Authorized" }, 401]
else
return ["Not Authorized", 401]
end
end
source_events = received_events.order(id: :desc).limit(events_to_show).to_a
interpolation_context.stack do
interpolation_context['events'] = source_events
items = source_events.map do |event|
interpolated = interpolate_options(options['template']['item'], event)
interpolated['guid'] = {'_attributes' => {'isPermaLink' => 'false'},
'_contents' => interpolated['guid'].presence || event.id}
date_string = interpolated['pubDate'].to_s
date =
begin
Time.zone.parse(date_string) # may return nil
rescue => e
error "Error parsing a \"pubDate\" value \"#{date_string}\": #{e.message}"
nil
end || event.created_at
interpolated['pubDate'] = date.rfc2822.to_s
interpolated
end
if format =~ /json/
content = {
'title' => feed_title,
'description' => feed_description,
'pubDate' => Time.now,
'items' => simplify_item_for_json(items)
}
return [content, 200]
else
content = Utils.unindent(<<-XML)
<?xml version="1.0" encoding="UTF-8" ?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
<channel>
<atom:link href=#{feed_url(secret: params['secret'], format: :xml).encode(xml: :attr)} rel="self" type="application/rss+xml" />
<atom:icon>#{feed_icon.encode(xml: :text)}</atom:icon>
<title>#{feed_title.encode(xml: :text)}</title>
<description>#{feed_description.encode(xml: :text)}</description>
<link>#{feed_link.encode(xml: :text)}</link>
<lastBuildDate>#{Time.now.rfc2822.to_s.encode(xml: :text)}</lastBuildDate>
<pubDate>#{Time.now.rfc2822.to_s.encode(xml: :text)}</pubDate>
<ttl>#{feed_ttl}</ttl>
XML
content += simplify_item_for_xml(items).to_xml(skip_types: true, root: "items", skip_instruct: true, indent: 1).gsub(/^<\/?items>/, '').strip
content += Utils.unindent(<<-XML)
</channel>
</rss>
XML
return [content, 200, 'text/xml']
end
end
end
private
class XMLNode
def initialize(tag_name, attributes, contents)
@tag_name, @attributes, @contents = tag_name, attributes, contents
end
def to_xml(options)
if @contents.is_a?(Hash)
options[:builder].tag! @tag_name, @attributes do
@contents.each { |key, value| ActiveSupport::XmlMini.to_tag(key, value, options.merge(skip_instruct: true)) }
end
else
options[:builder].tag! @tag_name, @attributes, @contents
end
end
end
def simplify_item_for_xml(item)
if item.is_a?(Hash)
item.each.with_object({}) do |(key, value), memo|
if value.is_a?(Hash)
if value.key?('_attributes') || value.key?('_contents')
memo[key] = XMLNode.new(key, value['_attributes'], simplify_item_for_xml(value['_contents']))
else
memo[key] = simplify_item_for_xml(value)
end
else
memo[key] = value
end
end
elsif item.is_a?(Array)
item.map { |value| simplify_item_for_xml(value) }
else
item
end
end
def simplify_item_for_json(item)
if item.is_a?(Hash)
item.each.with_object({}) do |(key, value), memo|
if value.is_a?(Hash)
if value.key?('_attributes') || value.key?('_contents')
contents = if value['_contents'] && value['_contents'].is_a?(Hash)
simplify_item_for_json(value['_contents'])
elsif value['_contents']
{ "contents" => value['_contents'] }
else
{}
end
memo[key] = contents.merge(value['_attributes'] || {})
else
memo[key] = simplify_item_for_json(value)
end
else
memo[key] = value
end
end
elsif item.is_a?(Array)
item.map { |value| simplify_item_for_json(value) }
else
item
end
end
end
end