Add support for contextual schema in validation

mrrobby · Jan 26, 2015 · ec14803 · ec14803
1 parent 63116ee
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Showing 3 changed files with 127 additions and 11 deletions.
diff --git a/README.md b/README.md
@@ -56,6 +56,86 @@ user.valid? # => false
 user.profile_invalid_json # => '{invalid JSON":}'
 ```
 
+#### Options
+
+| Option     | Description
+|------------|-----------------------------------------------------
+| `:schema`  | The JSON schema to validate the data against (see **JSON schema option** section)
+| `:message` | The ActiveRecord message added to the record errors (default: `:invalid_json`)
+
+##### JSON schema option
+
+You can specify four kinds of value for the `:schema` option.
+
+###### A path to a file containing a JSON schema
+
+```ruby
+class User < ActiveRecord::Base
+  # Constants
+  PROFILE_JSON_SCHEMA = Rails.root.join('config', 'schemas', 'profile.json_schema').to_s
+
+  # Validations
+  validates :profile, presence: true, json: { schema: PROFILE_JSON_SCHEMA }
+end
+```
+
+###### A Ruby `Hash` representing a JSON schema
+
+```ruby
+class User < ActiveRecord::Base
+  # Constants
+  PROFILE_JSON_SCHEMA = {
+    type: 'object',
+    :'$schema' => 'http://json-schema.org/draft-03/schema',
+    properties: {
+      city: { type: 'string', required: false },
+      country: { type: 'string', required: true }
+    }
+  }
+
+  # Validations
+  validates :profile, presence: true, json: { schema: PROFILE_JSON_SCHEMA }
+end
+```
+
+###### A plain JSON schema as a Ruby `String`
+
+```ruby
+class User < ActiveRecord::Base
+  # Constants
+  PROFILE_JSON_SCHEMA = '{
+    "type": "object",
+    "$schema": "http://json-schema.org/draft-03/schema",
+    "properties": {
+      "city": { "type": "string", "required": false },
+      "country": { "type": "string", "required": true }
+    }
+  }'
+
+  # Validations
+  validates :profile, presence: true, json: { schema: PROFILE_JSON_SCHEMA }
+end
+```
+
+###### A lambda that will get evaluated in the context of the validated record
+
+The lambda must return a valid value for the `:schema` option (file path, JSON `String` or Ruby `Hash`).
+
+```ruby
+class User < ActiveRecord::Base
+  # Constants
+  PROFILE_REGULAR_JSON_SCHEMA = Rails.root.join('config', 'schemas', 'profile.json_schema').to_s
+  PROFILE_ADMIN_JSON_SCHEMA = Rails.root.join('config', 'schemas', 'profile_admin.json_schema').to_s
+
+  # Validations
+  validates :profile, presence: true, json: { schema: lambda { dynamic_profile_schema } }
+
+  def dynamic_profile_schema
+    admin? ? PROFILE_ADMIN_JSON_SCHEMA : PROFILE_REGULAR_JSON_SCHEMA
+  end
+end
+```
+
 ## License
 
 `ActiveRecord::JSONValidator` is © 2013-2015 [Mirego](http://www.mirego.com) and may be freely distributed under the [New BSD license](http://opensource.org/licenses/BSD-3-Clause).  See the [`LICENSE.md`](https://github.com/mirego/activerecord_json_validator/blob/master/LICENSE.md) file.

diff --git a/lib/active_record/json_validator/validator.rb b/lib/active_record/json_validator/validator.rb
@@ -29,7 +29,8 @@ def validate_each(record, attribute, value)
     end
 
     # Validate value with JSON::Validator
-    errors = ::JSON::Validator.fully_validate(options.fetch(:schema), json_value)
+    schema = fetch_schema_for_record(record)
+    errors = ::JSON::Validator.fully_validate(schema, json_value)
 
     # Everything is good if we don’t have any errors and we got valid JSON value
     return true if errors.empty? && record.send(:"#{attribute}_invalid_json").blank?
@@ -60,4 +61,11 @@ def inject_setter_method(klass, attributes)
       RUBY
     end
   end
+
+  def fetch_schema_for_record(record)
+    schema = options.fetch(:schema)
+    return schema unless schema.is_a?(Proc)
+
+    record.instance_exec(&schema)
+  end
 end
diff --git a/spec/json_validator_spec.rb b/spec/json_validator_spec.rb
@@ -9,23 +9,36 @@
       end
     end
 
+    json_schema = schema
     spawn_model :User do
-      schema = {
-        type: 'object',
-        :'$schema' => 'http://json-schema.org/draft-03/schema',
-        properties: {
-          city: { type: 'string', required: false },
-          country: { type: 'string', required: true }
-        }
-      }
-
       serialize :profile, JSON
       validates :name, presence: true
-      validates :profile, presence: true, json: { schema: schema }
+      validates :profile, presence: true, json: { schema: json_schema }
+
+      def dynamic_json_schema
+        {
+          type: 'object',
+          :'$schema' => 'http://json-schema.org/draft-03/schema',
+          properties: {
+            foo: { type: 'string', required: false },
+            bar: { type: 'string', required: true }
+          }
+        }
+      end
     end
   end
 
   let(:user) { User.create(attributes) }
+  let(:schema) do
+    {
+      type: 'object',
+      :'$schema' => 'http://json-schema.org/draft-03/schema',
+      properties: {
+        city: { type: 'string', required: false },
+        country: { type: 'string', required: true }
+      }
+    }
+  end
 
   context 'with blank JSON value' do
     let(:attributes) { { name: 'Samuel Garneau', profile: {} } }
@@ -65,4 +78,19 @@
       expect(user.profile_invalid_json).to eql('foo:}bar')
     end
   end
+
+  context 'with lambda schema option' do
+    # The dynamic schema makes `country` and `city` keys mandatory
+    let(:schema) { lambda { dynamic_json_schema } }
+
+    context 'with valid JSON value' do
+      let(:attributes) { { name: 'Samuel Garneau', profile: { foo: 'bar', bar: 'foo' } } }
+      it { expect(user).to be_valid }
+    end
+
+    context 'with invalid JSON value' do
+      let(:attributes) { { name: 'Samuel Garneau', profile: {} } }
+      it { expect(user).not_to be_valid }
+    end
+  end
 end