Question

I am using ruby 1.9.2 and sinatra 1.3.2, Datamapper
I get error: “can’t convert nil into Hash”

in /new_record i have a form, and when submitting the form (with some blank fields) instead of getting validation messages i get this error!

here post ‘/new_record’ – because I populating this form with some values of previous form

post '/new_record' do
        @projects = Project.all
        @date = DateTime.parse(params[:report][:date])
        erb :new_record
      end

      post '/create_record' do
        @user = User.get(current_user.id)
        if @user.records.create(params[:record])
          flash(:notice => "Report created successfully!")
          redirect "/"
    else
      @projects = Project.all
      @date = DateTime.parse(params[:report][:date])
      erb :new_record
    end

I can’t guess why because similar form works well:

  get '/new' do
    #session[:user_id] = nil
    title "Create new account"
    erb :new_user
  end

  post '/create' do
   @user = User.new(params[:user])
   if @user.save
     session[:user_id] = nil
     redirect  "/"
   else
     erb :new_user
   end
  end

I think it is something with @user.records.create(params[:record]) with create method, that it tries to build hash, but why if it can’t build a hash just don’t throw error that it couldn’t save (build) @user.records dependency ?
Is there any way to work around this? Because I would like to build record using relationship.
Thanks in advice!

Answer 1

DataMapper is not throwing an error that it couldn’t save because it detects a problem even before it tries to save the record. (Also notice that, by default, DataMapper doesn’t throw exceptions anyway — you have to enable it.)

create takes a hash with the values you want to set as input. So, according to the mesasge you are reporting, apparently a nil was passed to it — and it’s complaining that it can’t convert a nil to a Hash.

Try something like this:

@user.records.create({:column => params[:record]})