Class: Line::Bot::V2::WebhookParser

Inherits:
Object
  • Object
show all
Defined in:
lib/line/bot/v2/webhook_parser.rb

Defined Under Namespace

Classes: InvalidSignatureError

Instance Method Summary collapse

Constructor Details

#initialize(channel_secret:, skip_signature_verification: nil) ⇒ WebhookParser

Initialize webhook parser

Parameters:

  • channel_secret (String) —

    The channel secret used for signature verification.

  • skip_signature_verification (() -) (defaults to: nil) —

    bool, nil] A callable object with type ‘() -> bool` that determines whether to skip webhook signature verification. Signature verification is skipped if and only if this callable is provided and returns `true`. This can be useful in scenarios such as when you’re in the process of updating the channel secret and need to temporarily bypass verification to avoid disruptions.



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# File 'lib/line/bot/v2/webhook_parser.rb', line 25

def initialize(channel_secret:, skip_signature_verification: nil)
  @channel_secret = channel_secret
  @skip_signature_verification = skip_signature_verification
end

Instance Method Details

#parse(body:, signature:) ⇒ Array<Line::Bot::V2::Webhook::Event>

Parse events from the raw request body and validate the signature.

Examples:

Sinatra usage

def parser
  @parser ||= Line::Bot::V2::WebhookParser.new(
    channel_secret: ENV.fetch("LINE_CHANNEL_SECRET"),
    skip_signature_verification: -> { ENV['SKIP_SIGNATURE_VERIFICATION'] == 'true' }
  )
end

post '/callback' do
  body = request.body.read
  signature = request.env['HTTP_X_LINE_SIGNATURE']

  begin
    events = parser.parse(body: body, signature: signature)
  rescue Line::Bot::V2::WebhookParser::InvalidSignatureError
    halt 400, { 'Content-Type' => 'text/plain' }, 'Bad Request'
  end

  # Handle events...
  events.each do |event|
    case event
    when Line::Bot::V2::Webhook::MessageEvent
      handle_message_event(event)
    ...
  end
  "OK"
end

Parameters:

  • body (String) —

    The unmodified request body (exactly as received).

  • signature (String) —

    The value of the ‘X-LINE-Signature’ header.

Returns:

  • (Array<Line::Bot::V2::Webhook::Event>) —

    An array of event objects. Recognized events become instances of classes under ‘Line::Bot::V2::Webhook::*Event`; `Line::Bot::V2::Webhook::Event` is returned as fallback only when the event class is not defined in line-bot-sdk library. When you update the SDK, you may not need to handle `Line::Bot::V2::Webhook::Event` anymore.

Raises:



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# File 'lib/line/bot/v2/webhook_parser.rb', line 71

def parse(body:, signature:)
  should_skip = @skip_signature_verification&.call || false

  unless should_skip == true || verify_signature(body: body, signature: signature)
    raise InvalidSignatureError.new("Invalid signature: #{signature}")
  end

  data = JSON.parse(body.chomp, symbolize_names: true)
  data = Line::Bot::V2::Utils.deep_underscore(data)
  data = Line::Bot::V2::Utils.deep_convert_reserved_words(data)
  data = Line::Bot::V2::Utils.deep_symbolize(data)

  data[:events].map do |event|
    Line::Bot::V2::Webhook::Event.create(**event) # steep:ignore
  end
end

#verify_signature(body:, signature:) ⇒ Object 



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# File 'lib/line/bot/v2/webhook_parser.rb', line 88

def verify_signature(body:, signature:)
  hash = OpenSSL::HMAC.digest(OpenSSL::Digest.new('SHA256'), @channel_secret, body)
  expected = Base64.strict_encode64(hash)
  variable_secure_compare(signature, expected)
end