Question

So basically I have a Book model that contains information like

• book title (string)
• author (string)
• description (text)
• etc.

Now on the front end I added the capability of dynamically adding more author fields. In the form I named it book[coauthor], so if I add a second author, I’d have a field book[coauthor][name_0].

What I’d like to achieve is combine book[author] and all book[coauthor][name_i] to one big string and separate each name with ,. (i.e. so with book[author] being “Alice” and book[coauthor][name_0] being “Bob” I should get “Alice,Bob” saved in book[author] in DB)

First Question: At this point is it better to do it with Javascript or with Rails (in controller)?

Second Questiion: Currently I’m doing it in the Rails controller but got Can't mass-assign protected attribute 'coauthor'. However I don’t want to make it a real attribute since all I need is some processing before saving all the information to the author field. What should I do?

Thanks guys.

Answer 1

The first question is a bit loaded, and you might get some heated disagreements but the way I look at it is this. Not everybody runs with Javascript enabled, so I make sure I have a way to do everything through Rails myself.

In this case, it’s actually quite easy.

The first thing I recommend is to not send the coauthors as part of the params[:book]. Instead, send them separately as a params[:coauthors]. Then in your controller you can do this:

@book = Book.new(params[:book])
@book.author = ([@book.author] + [params[:coauthors]]).join(",")
@book.save

Actually, it may be better to update params[:book][:author] since that would work for both create and update. Either way, I hope that helps.