[TAC061] Improve the length validation on the proposal body

ahukkanen · ahukkanen · commit 8f85e164b46d · 2020-04-01T03:34:42.000+03:00
diff --git a/decidim-core/lib/decidim/form_builder.rb b/decidim-core/lib/decidim/form_builder.rb
@@ -597,9 +597,16 @@ def string_or_symbol?(obj)
     # Returns an Integer or Nil.
     def length_for_attribute(attribute, type)
       length_validator = find_validator(attribute, ActiveModel::Validations::LengthValidator)
-      return unless length_validator
+      return length_validator.options[type] if length_validator
 
-      length_validator.options[type]
+      length_validator = find_validator(attribute, ProposalLengthValidator)
+      if length_validator
+        length = length_validator.options[type]
+        return length.call(object) if length.respond_to?(:call)
+        return length
+      end
+
+      nil
     end
 
     # Private: Finds a validator.
diff --git a/decidim-proposals/app/forms/decidim/proposals/proposal_wizard_create_step_form.rb b/decidim-proposals/app/forms/decidim/proposals/proposal_wizard_create_step_form.rb
@@ -13,7 +13,10 @@ class ProposalWizardCreateStepForm < Decidim::Form
 
       validates :title, :body, presence: true, etiquette: true
       validates :title, length: { in: 15..150 }
-      validates :body, length: { minimum: 15 }
+      validates :body, proposal_length: {
+        minimum: 15,
+        maximum: ->(record) { record.component.settings.proposal_length }
+      }
 
       validate :proposal_length
       validate :body_is_not_bare_template
diff --git a/decidim-proposals/app/validators/proposal_length_validator.rb b/decidim-proposals/app/validators/proposal_length_validator.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+# This validator takes care of ensuring the validated attributes are long enough
+# and not too long. The difference to the Rails length validator is that this
+# allows the minimum and maximum values to be lambdas allowing us to fetch the
+# maximum length dynamically for each proposals component.
+class ProposalLengthValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    return if value.blank?
+
+    validate_length(record, attribute, value)
+  end
+
+  private
+
+  def validate_length(record, attribute, value)
+    min = options[:minimum] || nil
+    min = min.call(record) if min.respond_to?(:call)
+    if min && min > 0 && value.length < min
+      record.errors.add(attribute, options[:message] || :too_short)
+    end
+
+    max = options[:maximum] || nil
+    max = max.call(record) if max.respond_to?(:call)
+    if max && max > 0 && value.length > max
+      record.errors.add(attribute, options[:message] || :too_long)
+    end
+  end
+end
