Class: Rack::Superfeedr

Inherits:
Object
  • Object
show all
Defined in:
lib/rack-superfeedr.rb

Overview

This is a Rack Middleware that can be used in your rack-compatible web framework (Rails, Sinatra…) to perform subscriptions over at superfeedr using the PubSubHubbub API.

Constant Summary collapse

SUPERFEEDR_ENDPOINT = 
"https://push.superfeedr.com"

Instance Method Summary collapse

Constructor Details

#initialize(app, params = {}, &block) ⇒ Superfeedr

When using this Rack, you need to supply the following params (2nd argument):

  • :host (the host for your web app. Used to build the callback urls.)

  • :login

  • :password

  • :format (atom|json, atom being default)

  • :async (true|false), false is default. You need to set that to false if you’re using platforms like Heroku that may disallow concurrency.

Raises:

  • (ArgumentError) 


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# File 'lib/rack-superfeedr.rb', line 102

def initialize(app, params = {}, &block)
  raise ArgumentError, 'Missing :host in params' unless params[:host]
  raise ArgumentError, 'Missing :login in params' unless params[:login]
  raise ArgumentError, 'Missing :password in params' unless params[:password]
  @callback = Proc.new { |notification, feed_id|
    # Bh default, do nothing
  }
  @verifications = {}
  @params = params
  @params[:port] = 80 unless params[:port]
  @app = app
  @base_path = params[:base_path] || '/superfeedr/feed/'
  block.call(self)
  self
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/rack-superfeedr.rb', line 129

def call(env)
  req = Rack::Request.new(env)
  if env['REQUEST_METHOD'] == 'GET' && feed_id = env['PATH_INFO'].match(/#{@base_path}(.*)/)
    # Verification of intent!
    if @verifications[feed_id[1]] && verification = @verifications[feed_id[1]][req.params['hub.mode']]
      # Check with the user
      if verification.call(req.params['hub.topic'], feed_id[1])
        Rack::Response.new(req.params['hub.challenge'], 200).finish
      else
        Rack::Response.new("not valid", 404).finish
      end
    else
      # By default, we accept all
      Rack::Response.new(req.params['hub.challenge'], 200).finish
    end
  elsif env['REQUEST_METHOD'] == 'POST' && feed_id = env['PATH_INFO'].match(/#{@base_path}(.*)/)
    # Notification
    content = nil
    # Body is a stream, not a string, so capture it once and save it
    body = req.body.read
    if env["CONTENT_TYPE"]
      content_type = env["CONTENT_TYPE"].split(";").first
    else
      content_type = "application/atom+xml" #default?
    end
    if content_type == "application/json"
      # Let's parse the body as JSON
      content = JSON.parse(body)
    elsif content_type == "application/atom+xml"
      # Let's parse the body as ATOM using nokogiri
      content = Nokogiri.XML(body)
    end
    # Let's now send that data back to the user.
    info = Hashie::Mash.new(req: req, body: body)
    if !@callback.call(content, feed_id[1], info)
      # We need to unsubscribe the user
    end
    Rack::Response.new("Thanks!", 200).finish
  else
    @app.call(env)
  end
end

#error ⇒ Object

Shows the latest error received by the API. Useful when a subscription or unsubscription request fails.



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# File 'lib/rack-superfeedr.rb', line 20

def error
  @error
end

#on_notification(&block) ⇒ Object

This allows you to define what happens with the notifications. The block passed in argument is called for each notification, with 2 arguments

  • the payload itself (ATOM or JSON, based on what you selected in the params)

  • the id for the feed, if you used any upon subscription



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# File 'lib/rack-superfeedr.rb', line 91

def on_notification(&block)
  @callback = block
end

#params ⇒ Object 



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# File 'lib/rack-superfeedr.rb', line 125

def params
  @params
end

#reset(params = {}) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/rack-superfeedr.rb', line 118

def reset(params = {})
  raise ArgumentError, 'Missing :host in params' unless params[:host]
  raise ArgumentError, 'Missing :login in params' unless params[:login]
  raise ArgumentError, 'Missing :password in params' unless params[:password]
  @params = params
end

#subscribe(url, id = nil, opts = {}, &block) ⇒ Object

Subscribe you to a url. id is optional, but recommanded has a unique identifier for this url. It will be used to help you identify which feed is concerned by a notification. The optional block will be called to let you confirm the subscription (or not). It returns true if the subscription was successful (or will be confirmed if you used async => true in the options), false otherwise. You can also pass an opts third argument that will be merged with the options used in Typhoeus’s Request (github.com/dbalatero/typhoeus) A useful option is :verbose => true for example.



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# File 'lib/rack-superfeedr.rb', line 31

def subscribe(url, id = nil, opts = {}, &block)
  feed_id = "#{id ? id : Base64.urlsafe_encode64(url)}"
  if block
    @verifications[feed_id] ||= {}
    @verifications[feed_id]['subscribe'] = block
  end
  endpoint = opts[:hub] || SUPERFEEDR_ENDPOINT
  opts.delete(:hub)

  if endpoint == SUPERFEEDR_ENDPOINT
    opts[:userpwd] = "#{@params[:login]}:#{@params[:password]}"
  end

  response = ::Typhoeus::Request.post(endpoint,
  opts.merge({
    :params => {
      :'hub.mode' => 'subscribe',
      :'hub.verify' => @params[:async] ? 'async' : 'sync',
      :'hub.topic' => url,
      :'hub.callback' =>  generate_callback(url, feed_id)
    },
    :headers => {
      :Accept => @params[:format] == "json" ? "application/json" : "application/atom+xml"
    }
  }))

  @error = response.body
  @params[:async] && response.code == 202 || response.code == 204 # We return true to indicate the status.
end

#unsubscribe(url, id = nil, opts = {}, &block) ⇒ Object

Unsubscribes a url. If you used an id for the susbcription, you need to use _the same_. The optional block will be called to let you confirm the subscription (or not). This is not applicable for if you use params => true It returns true if the unsubscription was successful (or will be confirmed if you used async => true in the options), false otherwise You can also pass an opts third argument that will be merged with the options used in Typhoeus’s Request (github.com/dbalatero/typhoeus) A useful option is :verbose => true for example.



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# File 'lib/rack-superfeedr.rb', line 67

def unsubscribe(url, id = nil, opts = {}, &block)
  feed_id = "#{id ? id : Base64.urlsafe_encode64(url)}"
  if block
    @verifications[feed_id] ||= {}
    @verifications[feed_id]['unsubscribe'] = block
  end
  response = ::Typhoeus::Request.post(SUPERFEEDR_ENDPOINT,
  opts.merge({
    :params => {
      :'hub.mode' => 'unsubscribe',
      :'hub.verify' => @params[:async] ? 'async' : 'sync',
      :'hub.topic' => url,
      :'hub.callback' =>  generate_callback(url, feed_id)
    },
    :userpwd => "#{@params[:login]}:#{@params[:password]}"
  }))
  @error = response.body
  @params[:async] && response.code == 202 || response.code == 204 # We return true to indicate the status.
end