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Form_for a Nested Resources Permissions (Y Model)

Answer 1

+2 A:

For the first error where you have a nil object you should pass in a blank object wherever you're passing objects to forms eg @permission ||= @project.permissions.new (assuming it's the permission object that is causing the nil object. Or to be fancier @project.permissions.find_or_initialize_by_user_id(params[:user_id]).

For the second error, It's odd that it's trying to map to destroy, it should be trying to map to the :update action right? run rake routes to see all routes in the application to verify that the PUT /projects/:project_id/permissions/:id action exists and maps to permissions#update

Jeremy 2010-10-12 05:07:00

@Jeremy, thanks for this... I just updated my permissions controller with your suggestion: "@permission = @project.permissions.find_or_initialize_by_user_id(params[:user_id])" No error there, but in the logs, it's not querying the permissions table.

AnApprentice 2010-10-12 05:24:02

@Jeremy, my mistake it is... Can you talk to me about the form where it shows the current setting if any and allows the user to modify... Is this the right setup? "<%=form_for [:project, @permission] do |f| %>"

AnApprentice 2010-10-12 05:26:27

Regarding Rake Routes, they look good, I'm guessing it's something to do with the form_for tag... "space_permission PUT /projects/:project_id/permissions/:id(.:format) {:controller=>"permissions", :action=>"update"}"

AnApprentice 2010-10-12 05:28:38

If I try "<%=form_for(@permission) do |f| %>" i get: "undefined method `permission_path' for #<#<Class:0x10305de18>:0x1030545c0>"

AnApprentice 2010-10-12 05:30:39

That would indicate that @permission isn't an instance of a Permission object. Try putting `debugger` just before your `form_for` call, and start your webserver with `rails server --debugger`. Check what's actually stored in the @permission object

Jeremy 2010-10-12 05:33:50

Very interesting, I haven't used that before.... Looking through the error now... In the debugger, I'm at line "@user = User.find(params[:user_id])" Looks like it isn't finding the user? "(rdb:2) @usernil(rdb:2) @user.inspect"nil"(rdb:2) params[:user_id]"13"(rdb:2) "

AnApprentice 2010-10-12 05:55:31

Strange: "@permission = @project.permissions.find_or_initialize_by_user_id(params[:user_id]) … (rdb:2) @permission ….. RETURNS: nil …. But (rdb:2) @project.permissions.find_or_initialize_by_user_id(params[:user_id]) DOES RETURN: #<Permission project_id: 3, role_id: 2, user_id: 13> Does that make any sense?

AnApprentice 2010-10-12 05:59:47

Ok I see, it shows me the line it's about to run... well in that case, it is getting the permission object. ANy thoughts on what the Form_For tag is supposed to look like?

AnApprentice 2010-10-12 06:02:27

@Jeremy. For a permission that does not currently exist, the form that renders looks good "<form method="post" id="new_permission" class="new_permission" action="/projects/3/permissions" accept-charset="UTF-8">" it's the existing records that are breaking it.

AnApprentice 2010-10-12 06:06:42

I got the form to work by using "<%=form_for [:project, @permission], :url => { :action => "update" } do |f| %>" What's confusing is, for a (Project, Role, User) record that does NOT exist in the DB table, the forms shows a record of it... Is that what the "find_or_initialize_by_user_id" is all about? That's confusing since it shows that role.id = 1, which is ADMIN, which is very untrue if a record does not exist... Is there a clever method that initalizes the user but with a Nil Role, forcing the admin to select the role?

AnApprentice 2010-10-12 06:17:46

`find_or_initialize` basically takes the conditions you're searching on (here that it would already belong to @project, and have the given user_id), if no record is found with these, then it essentially returns `@project.permissions.new(:user_id => params[:user_id])` (a new object which is not yet saved to the database). The reason for using this is that if you're passing in this blank object as opposed to nil, the form can detect what object you're wanting to create (because the record doesn't exist, it should automatically route to permissions#create instead of permissions#update).

Jeremy 2010-10-12 10:00:23

In the code you've just posted to make it work for #update that may break for permissions that don't exist yet. It's a bit ugly but you could try using `<%=form_for [:project, @permission], :url => { :action => (@permission.new_record? ? "create" : "update") } do |f| %>` (new_record? returns true if @permission is an object which does not yet exist in the database).

Jeremy 2010-10-12 10:03:13

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Form_for a Nested Resources Permissions (Y Model)

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