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Inconsistence between CachedResourcesProcessor#process_resources vs SimpleResourcesProcessor#process_resources #31
Description
When I start implementing caching in my app, I noticed CachedResourcesProcessor#process_resources returns an array of strings, but SimpleResourcesProcessor#process_resources returns an array of hashes.
I assume the api should expect to return an array of hashes, so that when Rails' controllers calls render in jsonapi-rails, it converts that data hash into json correctly, but if it's a string, it will to_json again on string which I don't think we want that behaviour.
Option 1
Change CachedResourcesProcessor#process_resources to return array of hash:
def process_resources
[@primary, @included].each do |resources|
cache_hash = cache_key_map(resources)
processed_resources = @cache.fetch_multi(*cache_hash.keys) do |key|
res, include, fields = cache_hash[key]
json = res.as_jsonapi(include: include, fields: fields).to_json
JSONString.new(json)
end
values = processed_resources.values.map { |json| JSON.parse(json) }
resources.replace(values)
end
endPros: Consistency API.
Cons: It's a bit slow if we do with big data because it has to convert json data back and forth.
Option 2
Change jsonapi-rails to not calling to_json again if it's already in string.
::ActionController::Renderers.add(name) do |resources, options|
# Renderer proc is evaluated in the controller context.
self.content_type ||= Mime[:jsonapi]
ActiveSupport::Notifications.instrument('render.jsonapi-rails',
resources: resources,
options: options) do
data = renderer.render(resources, options, self)
data.is_a?(String) ? data : data.to_json
end
endPros: It's fast because we don't need to do double works on converting json data.
Cons: Inconsistency API between CachedResourcesProcessor#process_resources vs SimpleResourcesProcessor#process_resources.
Edit: Option 2 is not working because renderer.render(resources, options, self) return jsonapi respone data hash not just data attribute.
Activity
samnang commentedon Dec 21, 2017
After I investigate the issue, it seems
JSONAPI::Renderer::CachedResourcesProcessor::JSONString#to_jsonis never run.What we expect the return value should be
"{\"data\":{\"id\": \"1\"}}"I am on Rails 5.1.4.
beauby commentedon Dec 21, 2017
Hi @samnang – you are right. There is a fix for Rails 5 in jsonapi-rb/jsonapi-rails#70, and I'll try to cut new releases of all gems next week.
In the meantime, in order to use caching, you should add the following to your Gemfile:
samnang commentedon Dec 21, 2017
Thank @beauby, you saved my day. I have been tried different options to get it to work, but none of them are good.
samnang commentedon Dec 21, 2017
@beauby I have few questions that try to understand how the caching work here:
cacheoption in my index action for rendering collection, does it cache individual resource within collection separately or cache the entire collection?beauby commentedon Jan 5, 2018
Hi @samnang
Not sure I understand, but what is cached is a fragment of JSON representing a resource (along with its relationships' linkage data).
Each resource will be fetched (though using
fetch_multi).It caches individual resources.