Default date serialization

[Simon Huber]

I created a Blueprint like that:

class FirstBlueprint < Blueprinter::Base
  identifier :id

  fields :title, :starts_at, :ends_at
end

What i found out a bit later is, that the date got printed out that way: "2022-08-05 22:38:22 +0200"

Now why is that problematic?

Firefox and Safari won't be able to parse dates in JS like that:

-> new Date('2021-11-23 11:56:20 +0100')
=> Invalid Date

-> new Date('2021-11-23T11:56:15+01:00')
=> Tue Nov 23 2021 11:56:15 GMT+0100 (Central European Standard Time)

I just see a lot of errors occurring out of that, because it's not the expected behaviour. If you do:

[0] pry(main)> { myDate: Time.zone.now }.to_json

Rails will perfectly handle that and convert it to a ISO8601. Therefore i think a blueprint should do the same?

What i asked myself? Is it not intended to use a date as a field? In the documentation i just read, that i could define a custom date format, but not, that it's needed for date fields.

Suggestion:

I would love a default configuration for dates. So that in the background it's checking by default something like field.is_a?(Date) || field.is_a?(DateTime) ? field.iso8601 : field

What do you think?

[Ben Blue]

I ran into this problem myself recently. It's tricky to solve in a straightforward way. Caveat: this is a Rails project that is not using OJ or yajl-ruby.

You can use the Blueprinter.configuration.datetime_format option, but unfortunately, setting that option means Date/DateTime values will be formatted as strings if you're relying on render_to_hash anywhere, which seems incorrect. If you don't care about that, you can use just use the config option and it will format any object responding to strftime -- so both Date and DateTime will be fine.

Even more unexpected is the behavior of render vs render_as_json in a Rails project. render_as_json just calls as_json which means it uses the ActiveSupport::JSON methods, including these options:

ActiveSupport::JSON::Encoding.use_standard_json_time_format
ActiveSupport::JSON::Encoding.escape_html_entities_in_json
ActiveSupport::JSON::Encoding.time_precision
ActiveSupport::JSON::Encoding.json_encoder 

render by default calls JSON.generate which ActiveSupport::JSON takes care not to override, so the formatting will be different depending on the value of ActiveSupport::JSON::Encoding.use_standard_json_time_format:

# render_as_json
"updatedAt"=>"2021-12-20T18:04:43.311Z"

# render
\"updatedAt\":\"2021-12-20 18:04:43 UTC\"

If you just want the default Rails behavior, and you're not using a different generator like OJ, you can use this configuration:

Blueprinter.configure do |config|
  config.method = :encode
  config.generator = ActiveSupport::JSON
end

[Josh Rohrbaugh]

different but related issue I just discovered:

setting Blueprinter.configuration.datetime_format will format DateTime values defined as fields, but it will not transform DateTimes passed through the meta hash

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.