Gab Social. All are welcome.

app/services/subscribe_service.rb

@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+class SubscribeService < BaseService
+  def call(account)
+    return if account.hub_url.blank?
+
+    @account        = account
+    @account.secret = SecureRandom.hex
+
+    build_request.perform do |response|
+      if response_failed_permanently? response
+        # We're not allowed to subscribe. Fail and move on.
+        @account.secret = ''
+        @account.save!
+      elsif response_successful? response
+        # The subscription will be confirmed asynchronously.
+        @account.save!
+      else
+        # The response was either a 429 rate limit, or a 5xx error.
+        # We need to retry at a later time. Fail loudly!
+        raise GabSocial::UnexpectedResponseError, response
+      end
+    end
+  end
+
+  private
+
+  def build_request
+    request = Request.new(:post, @account.hub_url, form: subscription_params)
+    request.on_behalf_of(some_local_account) if some_local_account
+    request
+  end
+
+  def subscription_params
+    {
+      'hub.topic': @account.remote_url,
+      'hub.mode': 'subscribe',
+      'hub.callback': api_subscription_url(@account.id),
+      'hub.verify': 'async',
+      'hub.secret': @account.secret,
+      'hub.lease_seconds': 7.days.seconds,
+    }
+  end
+
+  def some_local_account
+    @some_local_account ||= Account.local.without_suspended.first
+  end
+
+  # Any response in the 3xx or 4xx range, except for 429 (rate limit)
+  def response_failed_permanently?(response)
+    (response.status.redirect? || response.status.client_error?) && !response.status.too_many_requests?
+  end
+
+  # Any response in the 2xx range
+  def response_successful?(response)
+    response.status.success?
+  end
+end