Pass request params to ActionMailer::Preview

[ixti]

Allows passing query params to email previews:

http://localhost:3000/rails/mailers/user_mailer/password_recovery?email=alice@foobar.com

[rails-bot]

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[ixti]

This is mostly a discussion starter. So if this is "acceptable" idea, I will add specs for changes.

[prathamesh-sonpatki]

cc @pixeltrix

There was some interest in having this feature.

[sethherr]

I'm also very interested in this - essentially a solution to #21702 with @pixeltrix's suggestion.

@ixti - have you written specs for this change?

[ixti]

@sethherr finally, yes.

@sgrif sorry it took me so long to get back to this PR, but, finally it's ready for review :D

[pixeltrix]

I'm not sure of the worth of this test as it stands - I think it needs breaking out into a separate preview test case file and then actually testing the content of params changes the output. I know that the railties test does that but we should probably have a unit test that does it as well because not everyone runs the railties tests 😉

[ixti]

Do you propose to extract that into a separate file? I'm not sure I fully understand your proposal.

[eric1234]

Shouldn't the railties template be updated so that the params are passed into the iframe. Otherwise the body of the message won't get the same params...

https://github.com/rails/rails/blob/master/railties/lib/rails/templates/rails/mailers/email.html.erb#L110

[ixti]

@eric1234 Oh. Indeed! Thanks! Will fix that!

[eric1234]

@ixti - Also the dropdown that selects the part being viewed.

[ixti]

@eric1234 thanks again. I really completely forgot about views :D

[ixti]

@eric1234 fixed view templates and extended test to cover that.
@pixeltrix can you explain your comment, please?
@sgrif review, please.

[ixti]

@sgrif I have rebased PR upon master. Still waiting for a review. If there's no interest in this PR, please, close it.

[sgrif]

I'm on parental leave for the next few months. I'll defer to someone else on this.

r? @pixeltrix

[ixti]

Is there still any interest in this PR? @pixeltrix

[ixti]

I assume silence and ignore means no interest.