ActiveRecord::AssociationTypeMismatch

rubyonrails-talk
1

Hi to all, I have this error and I don't understand why. I have three model, Image and Playlist and PlaylistItem. Everything works fine. The app should work also a XML REST service. When I made this call I obtain this XML because the playlist don't contains images:

GET http://0.0.0.0:3000/playlists/7.xml <playlist>   <id>7</id>   <name>metallo</name>   <images></images> </playlist>

I would put some images in playlist (the images are already presents on server) I should made this call:

PUT http://0.0.0.0:3000/playlists/7.xml

<playlist>     <id>7</id>     <name>metal</name>     <images>         <image>             <id>1</id>             <name>gino</name>         </image>         <image>             <id>2</id>             <name>pino</name>         </image>     </images> </playlist>

but I obtain this error:

ActiveRecord::AssociationTypeMismatch in PlaylistsController#update Image(#87559180) expected, got Array(#78093260)

parameters: {"playlist"=>{"id"=>"7", "name"=>"metal", "images"=>{"image"=>[{"id"=>"1", "name"=>"gino"}, {"id"=>"2", "name"=>"pino"}]}}, "id"=>"7", "format"=>"xml"}

This are the three models:

class Image < ActiveRecord::Base   attr_accessor :picture   validates :name, :uniqueness => true, :presence => true   validates :picture, :presence => true

  has_many :playlist_items   has_many :playlists, :through => :playlist_items end

class Playlist < ActiveRecord::Base   validates :name, :presence => true, :uniqueness => true

  has_many :playlist_items   has_many :images, :through => :playlist_items   accepts_nested_attributes_for :images, :allow_destroy => true end

class PlaylistItem < ActiveRecord::Base   belongs_to :image   belongs_to :playlist end

The project can be found here: GitHub - gpad/rms: Exmample REST server with file upload

can anybody help?

thanks Gianluca

2

Looks like you need a slightly different format for the XML:

--Matt Jones

3

I got also faced this error . when I was using same column name in two different tables and trying to access them.I renamed the column in one of the tables and it started working.

–RorUser

4

Gracias el de una semana es para la semana del 4 al 10. De diciembre

SERGIO

5

I try this type of XML

<playlist>   <id>7</id>   <name>metal</name>   <images_attributes type="array">     <image>       <id>3</id>     </image>   </images_attributes> </playlist>

but I receive this error:

Couldn't find Image with ID=3 for Playlist with ID=7

app/controllers/playlists_controller.rb:43:in `block in update' app/controllers/playlists_controller.rb:42:in `update'

"playlist"=>{"id"=>"7", "name"=>"metal", "images_attributes"=>[{"id"=>"3"}]}, "id"=>"7", "format"=>"xml"}

The image ID 3 already exist!

It's very strange ... I don't think I'm in a case corner, It's common in REST service have this type of information ...

bye Gianluca

6

Hi to all, I think I have understand the problem. When you made a PUT of this type:

<playlist> <id>7</id> <name>metal</name> <images_attributes type="array">    <image>      <id>3</id>    </image> </images_attributes> </playlist>

Rails suppose that:

Or your are creating the playlist and the image or you are updating the relationship inside the playlist, see the method assign_nested_attributes_for_collection_association in activerecord-3.0.10/lib/active_record/associations/has_many_through_association.rb

In may case I have already all the image in the play list and I would create a playlist selecting some images ...

How can I obtain this behavior?

thanks Gianluca