multiparameter error with datetime_select

Question

I have the following code in my form.

<%= f.datetime_select(:date_time, :prompt => {:day => \'Day\', :month => \'Month\', :year => \'Year\'},          


        

Answer 1

Christian. This is a bug in Rails that checks the database to infer the type needed for the multiparameter attributes. My guess is that your "date_time" attribute is not associated with a time column in your database.

I recently tackled this problem where I wanted a non-database attribute to accepted multiparameter attributes, this was the best solution I could come up with:

I found myself wanting to set an attr_accessor to handle passing a date to my model in a form_for tag with the f.datetime_select helper. So this is what I had:

Model:

attr_accessor :my_time

View:

<%= f.datetime_select :my_time %>

Unfortunately when I submit my form I get this:

1 error(s) on assignment of multiparameter attributes

Well it turns out that this is actually a Rails bug a ticket for which has been submitted. In the meantime how do we make this work? The only solution I could find that was remotely attractive was to make use of composed_of as a replacement for attr_accessor. so...

Model:

  composed_of :my_time,
              :class_name => 'Time',
              :mapping => %w(Time to_s),
              :constructor => Proc.new{ |item| item },
              :converter => Proc.new{ |item| item }

I know almost nothing about the composed_of method so you should probably do your own reading on it, but what I do know is that it creates both a reader and writer for the given instance variable, and more importantly, the setter accepts multiparameter attributes. How I chose the options:

class_name: the name of our expected class. In this case, Time
mapping: the first argument is the class and the second argument seems to work with any method that an instance of the class responds to. I chose to_s constructor: Not really sure how this is supposed to work. Seems to be called when @my_time is nil.
converter: Not really sure how this is supposed to work. Seems to be called when from my_time=, but doesn't seem to be applied with mass assignment. One problem I ran into with this solution was that times were getting set in UTC instead of the environment's time zone. So unfortunately we cannot use my_time directly, but instead need to convert it to the proper time zone:

Time.zone.parse(my_time.to_s(:number))

Answer 2

What Does ActiveRecord::MultiparameterAssignmentErrors Mean?

def initialize(attributes={})
  date_hack(attributes, "deliver_date")
  super(attributes)
end   

def date_hack(attributes, property)
  keys, values = [], []
  attributes.each_key {|k| keys << k if k =~ /#{property}/ }.sort
  keys.each { |k| values << attributes[k]; attributes.delete(k); }
  attributes[property] = values.join("-")
end

Answer 3

I was facing the same problem. I just added attr_accessible for that attribute and it works fine.

Hope it helps.

Answer 4

Remove :include_blank => false from your code.

<%= f.datetime_select(:date_time, :prompt => {:day => 'Day', :month => 'Month', :year => 'Year'}, :start_year => Date.today.year, :end_year => Date.today.year + 2, :minute_step => 15 %>

Thanks....

Answer 5

I had the same problem using a date dropdown that wasn't backed by a database attribute. I wrote a little Rack middleware to cope with the problem:

class DateParamsParser
  def initialize(app)
    @app = app
  end

  def call(env)
    if %w{POST PUT}.include? env['REQUEST_METHOD']
      params = Rack::Utils.parse_query(env["rack.input"].read, "&")

      # selects only relevant params like 'date1(1i)'
      filtered_params = params.select{ |key, value| key =~ /\(\di\)/ }
      # delete date params
      filtered_params.each { |key, value| params.delete(key) }

      # returns something like {'date1' => [2012, 5, 14], 'date2' => [2002, 3, 28]}
      date_array_params = filtered_params.sort.reduce({}) do |array_params, keyvalue|
        date_key = keyvalue.first.match(/(.+)\(/)[1] + ']'
        array_params[date_key] ||= []
        array_params[date_key] << keyvalue.last
        array_params
      end

      # Creates params with date strings like {'date1' => '2012-5-14', 'date2' => '2002-3-28'}
      date_params = Hash[date_array_params.map{ |key, date_array| [key, date_array.join('-')] }]

      params.merge! date_params
      env["rack.input"] = StringIO.new(Rack::Utils.build_query(params))
      env["rack.input"].rewind
    end

    @app.call(env)
  end
end

And in application.rb I put

config.middleware.insert_before ActionDispatch::ParamsParser, "DateParamsParser"

Note that I only build a date string here. So if you also require time you'll need to build the date_params differently.

Answer 6

I faced the same problem with the model below

class Reservation < ActiveRecord::Base
    attr_accessor :sid, :check_in, :credit_card_number, :expiration_date
    attr_accessible :expiration_date
end

The corresponding form with the field for the expiration date:

<div class="field">
  <%= f.label :expiration_date %>
  <%= f.date_select(:expiration_date, start_year: Time.now.year + 3, :end_year => Time.now.year - 3, discard_day: true) %>
</div>

as mentioned by @gabeodess the problem is checking the database to infer the type accordingly the solution I did for it was adding the following code to the model to put the type of the needed attribute in this case :expiration_date so the model is modified to be the following

class Reservation < ActiveRecord::Base
  attr_accessor :sid, :check_in, :credit_card_number, :expiration_date
  attr_accessible :expiration_date
  columns_hash["expiration_date"] = ActiveRecord::ConnectionAdapters::Column.new("expiration_date", nil, "date")
end

Hope this is useful