fix: validate template_params for WhatsApp (#6881)

- Add JsonSchemaValidator, which takes a declarative schema and validates it for a given property.
- Add specs for JsonSchemaValidator
- Enable the validator for template_params

app/models/concerns/json_schema_validator.rb

@@ -0,0 +1,84 @@
+# This file defines a custom validator class `JsonSchemaValidator` for validating a JSON object against a schema.
+# To use this validator, define a schema as a Ruby hash and include it in the validation options when validating a model.
+# The schema should define the expected structure and types of the JSON object, as well as any validation rules.
+# Here's an example schema:
+#
+# schema = {
+#   'type' => 'object',
+#   'properties' => {
+#     'name' => { 'type' => 'string' },
+#     'age' => { 'type' => 'integer' },
+#     'is_active' => { 'type' => 'boolean' },
+#     'tags' => { 'type' => 'array' },
+#     'address' => {
+#       'type' => 'object',
+#       'properties' => {
+#         'street' => { 'type' => 'string' },
+#         'city' => { 'type' => 'string' }
+#       },
+#       'required' => ['street', 'city']
+#     }
+#   },
+#   'required': ['name', 'age']
+# }.to_json.freeze
+#
+# To validate a model using this schema, include the `JsonSchemaValidator` in the model's validations and pass the schema
+# as an option:
+#
+# class MyModel < ApplicationRecord
+#   validates_with JsonSchemaValidator, schema: schema
+# end
+
+class JsonSchemaValidator < ActiveModel::Validator
+  def validate(record)
+    # Get the attribute resolver function from options or use a default one
+    attribute_resolver = options[:attribute_resolver] || ->(rec) { rec.additional_attributes }
+
+    # Resolve the JSON data to be validated
+    json_data = attribute_resolver.call(record)
+
+    # Get the schema to be used for validation
+    schema = options[:schema]
+
+    # Create a JSONSchemer instance using the schema
+    schemer = JSONSchemer.schema(schema)
+
+    # Validate the JSON data against the schema
+    validation_errors = schemer.validate(json_data)
+
+    # Add validation errors to the record with a formatted statement
+    validation_errors.each do |error|
+      # byebug
+      format_and_append_error(error, record)
+    end
+  end
+
+  private
+
+  def format_and_append_error(error, record)
+    return handle_required(error, record) if error['type'] == 'required'
+
+    type = error['type'] == 'object' ? 'hash' : error['type']
+
+    handle_type(error, record, type)
+  end
+
+  def handle_required(error, record)
+    missing_values = error['details']['missing_keys']
+    missing_values.each do |missing|
+      record.errors.add(missing, 'is required')
+    end
+  end
+
+  def handle_type(error, record, expected_type)
+    data = get_name_from_data_pointer(error)
+    record.errors.add(data, "must be of type #{expected_type}")
+  end
+
+  def get_name_from_data_pointer(error)
+    data = error['data_pointer']
+
+    # if data starts with a "/" remove it
+    data[1..] if data[0] == '/'
+  end
+end

app/models/message.rb

@@ -37,12 +37,33 @@ class Message < ApplicationRecord
   include Liquidable
   NUMBER_OF_PERMITTED_ATTACHMENTS = 15
 
+  TEMPLATE_PARAMS_SCHEMA = {
+    'type': 'object',
+    'properties': {
+      'template_params': {
+        'type': 'object',
+        'properties': {
+          'name': { 'type': 'string' },
+          'category': { 'type': 'string' },
+          'language': { 'type': 'string' },
+          'namespace': { 'type': 'string' },
+          'processed_params': { 'type': 'object' }
+        },
+        'required': %w[name category language namespace processed_params]
+      }
+    }
+  }.to_json.freeze
+
   before_validation :ensure_content_type
 
   validates :account_id, presence: true
   validates :inbox_id, presence: true
   validates :conversation_id, presence: true
   validates_with ContentAttributeValidator
+  validates_with JsonSchemaValidator,
+                 schema: TEMPLATE_PARAMS_SCHEMA,
+                 attribute_resolver: ->(record) { record.additional_attributes }
+
   validates :content_type, presence: true
   validates :content, length: { maximum: 150_000 }