JSON API for listing messages and their metadata

[kmarsh]

Adds a JSON API for listing messages and their metadata:

GET /letter_opener.json

[
  {
    "from": "App <notifications@example.com>",
    "id": "1531326085_772435_3ec1a42",
    "subject": "Retailer accepted your invitation!",
    "to": "Rebekah_Borer@gmail.com"
  },
  {
    "from": "App <notifications@example.com>",
    "id": "1531326065_158782_e7bf42c",
    "subject": "You have been invited to participate!",
    "to": "Laurie18@yahoo.com"
  }
]

Also:

• Adds an optional /raw parameter to LettersController#show access a message without letter_opener's iframe wrapper.
• Fixes some Rubocop errors (not in my changes) that were preventing a push

This was adding to make end-to-end testing with Cypress, etc. easier.

[kmarsh]

Looks like this build is failing on Ruby 2.1 because Rubocop doesn't support it. That's a pretty old version of Ruby, no longer supported. Should I remove it from Travis?

[fgrehm]

Hey @kmarsh! Sorry for the silence but what's the use case here? You mentioned end to end testing with cypress but I wonder how you plan to use it.

I've personally only used this gem in development environments. I know some people use it on staging envs but it's the first time I hear about usage for tests!

cc @pseudomuto in case you have any thoughts too

[kmarsh]

I was using it to verify emails were sent during an integration test. I ended up rolling off that particular project but I still think it’d be useful for that use case and would be happy to get the PR into shape once Travis is fixed.

[fgrehm]

once Travis is fixed.

Master is currently green 😄

[fgrehm]

Hi @kmarsh! CI has been fixed and moved over to github actions and we now have a 2.0 release, if you or anyone else is interested in pursuing this please open up a new PR and I'll be more than happy to help review and release!

In any case, thanks for the PR and interest in contributing with the project!