InvalidSymbolKey error when using symbol keys in schema

[stanig2106]

Hello,

I'm currently using the activerecord_json_validator gem in a project and I've come across an issue when I use symbol keys in the JSON schema. Here's the code where the issue arises:

validates :data, json: {
  schema: {
    type: :object,
    properties: {
      time: { type: :number, minimum: 0 }
    },
    required: %i[time]
  }
}

When I run this, I get the following error:

JSONSchemer::InvalidSymbolKey: schemas must use string keys

This error seems to be raised from the JSONSchemer::Schema::Base#initialize method when the schema is a Hash, is not empty, and the first key in the schema is not a string. Here's the code block where this happens:

raise InvalidSymbolKey, 'schemas must use string keys' if schema.is_a?(Hash) && !schema.empty? && !schema.first.first.is_a?(String)

Proposed Solution:

As a simple fix for this issue, instead of raising an error when the schema contains symbol keys, the schema could be modified to convert all keys to strings. We can use Hash#deep_stringify_keys (from active_support) method on the schema.

This change would make the gem more flexible and user-friendly by eliminating the need for users to ensure that their schemas only use string keys. I believe this would be a beneficial change and would appreciate if it could be considered for implementation.

Thank you for your time and consideration.

Best,
Stani

[remi]

Hi @stanig2106,

You’re right, json_schemer produces this error when symbols are used as keys for the schema.

I don’t think we should circumvent this limitation in ActiveRecord::JSONValidator though, we don’t want to add and maintain an additional logic layer between us and json_schemer when passing hashes as the schema.

What I would suggest is that you explicitly convert symbols to strings:

validates :data, json: {
  schema: {
    type: :object,
    properties: {
      time: { type: :number, minimum: 0 }
    },
    required: %i[time]
  }.deep_stringify_keys
}

Hope that helps!

[davishmcclurg]

This would be partially covered by upgrading to json_schemer 2.0: #78
Symbol keys are supported, but not symbol values (eg, type: 'object' works but not type: :object)