Handle exceptions

app/controllers/application_controller.rb

@@ -47,4 +47,94 @@ def clear_mdc_context
       org.slf4j.MDC.remove(key)
     end
   end
+
+  # Note! Order matters, StandardError needs to be first
+  rescue_from(StandardError) do |error|
+    flash[:error] = "Error: #{as_string(error)}"
+    try_to_redirect_to_account_path = !params[:controller].ends_with?('accounts')
+    perform_redirect_after_error try_to_redirect_to_account_path
+  end
+
+  rescue_from(ActionController::ParameterMissing) do |parameter_missing_exception|
+    log_rescue_error parameter_missing_exception
+    flash[:error] = "Required parameter missing: #{parameter_missing_exception.param}"
+    perform_redirect_after_error
+  end
+
+  rescue_from(KillBillClient::API::ResponseError) do |killbill_exception|
+    flash[:error] = "Error while communicating with the Kill Bill server: #{as_string(killbill_exception)}"
+    try_to_redirect_to_account_path = !killbill_exception.is_a?(KillBillClient::API::Unauthorized) && !(killbill_exception.is_a?(KillBillClient::API::NotFound) && params[:controller].ends_with?('accounts'))
+    perform_redirect_after_error try_to_redirect_to_account_path
+  end
+
+  private
+
+  def nested_hash_value(obj, key)
+    if obj.respond_to?(:key?) && obj.key?(key)
+      obj[key]
+    elsif obj.is_a?(Hash) || obj.is_a?(Array)
+      r = nil
+      obj.find { |*a| r = nested_hash_value(a.last, key) }
+      r
+    else
+      nil
+    end
+  end
+
+  def as_string(exception)
+    if exception.is_a?(KillBillClient::API::ResponseError)
+      as_string_from_response(exception.response.body)
+    elsif exception.is_a?(ActionController::ParameterMissing)
+      # e.message contains corrections, which we don't want
+      "missing parameter #{exception.param}"
+    elsif exception.respond_to?(:cause) && !exception.cause.nil?
+      as_string(exception.cause)
+    else
+      log_rescue_error(exception)
+      exception.message
+    end
+  end
+
+  def as_string_from_response(response)
+    error_message = response
+    begin
+      # BillingExceptionJson?
+      error_message = JSON.parse response
+    rescue StandardError => _e
+      # Ignore
+    end
+
+    if error_message.respond_to?(:[]) && error_message['message'].present?
+      # Likely BillingExceptionJson
+      error_message = error_message['message']
+      error_message += " (code=#{error_message['code']})" unless error_message['code'].blank?
+    end
+    # Limit the error size to avoid ActionDispatch::Cookies::CookieOverflow
+    error_message[0..1000]
+  end
+
+  def current_tenant_user
+    user = current_user
+    kb_tenant_id = session[:kb_tenant_id]
+    user_tenant = Kaui::Tenant.find_by_kb_tenant_id(kb_tenant_id) if kb_tenant_id
+    result = {
+        :username => user.kb_username,
+        :password => user.password,
+        :session_id => user.kb_session_id,
+    }
+    if user_tenant
+      result[:api_key] = user_tenant.api_key
+      result[:api_secret] = user_tenant.api_secret
+    end
+    result
+  end
+
+  def perform_redirect_after_error(try_to_redirect_to_account_path = true)
+    account_id = nested_hash_value(params.permit!.to_h, :account_id)
+    if try_to_redirect_to_account_path && account_id.present?
+      redirect_to kaui_engine.account_path(account_id)
+    else
+      redirect_to kaui_engine.home_path
+    end
+  end
 end