class List
include DataMapper::Resource
property :id, Serial
property :name, String
property :items, String
end
List.auto_migrate!
get '/:id' do
#list = List.all(:id => params[:id])
#items = #list.items
erb :show
end
I get undefined method `items' for #. Any ideas?
You fetch a collection of lists instead of a single list instance, that's why you get the error. I believe you want to do:
#list = List.get(params[:id])
Related
I have used this method before in a Sinatra application with Datamapper without any troubles.
Now it doesn't seem to work. Any ideas appreciated.
My test:
scenario 'add hashtags to posts' do
visit '/'
add_post('Stacca',
'Hello! out there',
%w(foo bar))
post = Post.first
expect(post.hashtag.map(&:text)).to include('foo')
expect(post.hashtag.map(&:text)).to include('bar')
end
My server
post '/posting' do
username = params['username']
message = params['message']
hashtag = params['hashtag'].split(' ').map do |hashtag|
hashtag.first_or_create(text: hashtag)
end
Post.create(username: username, message: message, hashtag: hashtag)
redirect to ('/')
end
My Models:
class Post
include DataMapper::Resource
property :id, Serial
property :username, String
property :message, String
has n, :hashtag, through: Resource
end
and:
class Hashtag
include DataMapper::Resource
has n, :posts, through: Resource
property :id, Serial
property :text, String
end
Thank you
This line:
hashtag.first_or_create(text: hashtag)
should be:
Hashtag.first_or_create(text: hashtag) # uppercase!
Else, you are just trying to call a non existing "first_or_create" method on the String ("foo") you got from the scenario. 'Hashtag' is your class, 'hashtag' is your (String) variable.
Hashtag.first_or_create(text: hashtag)
Hashtag should have been a class
i.e. you missed the capital
I have this model:
class CompanyCrawler < ActiveRecord::Base
....
serialize :entry_pages, Array
def entry_page_objects
entry_pages.map { |url| EntryPage.new(url) }
end
def entry_page_objects_attributes=(attributes)
# ...
end
....
end
This form to render the model:
.....
%p
%p
= crawler_form.label 'Entry pages'
= crawler_form.text_area :entry_pages_text, size: '80x6'
%ul.entry-pages
= crawler_form.fields_for :entry_page_objects do |entry_page_field|
%li=entry_page_field.text_field :url, size: 80
%a{href: '#', class: 'add-button'} Add Entry Page
The problem I have is that the form renders the entry_page_object input names incorrectly(e.g. company_crawler[entry_page_objects_attributes][0][url] instead of company_crawler[entry_page_objects][0][url]). I am really not sure what to do, I have read the documentation and the example says that just by defining attr_attributes=(attributes) and persisted? I will be able to use fields_for for collections just if they were associations defined with accept_nested_fields.
I have seen different solutions like just giving String 'entry_page_objects[]' to fields_for but I want to be consistent with rails naming convention and I know I can use form_tag instead of form_for but I want to make fields_for work as expected.
Here is some information for all that have not understood properly how nested_attributes works, like me.
What I have reported as issue is actually how it is supposed to work. When we have, let say, this model:
class Foo < ActiveRecord::Base # it has name attribute
has_many :larodis
accepts_nested_attributes_for :larodi
end
class Larodi < ActiveRecord::Base # it has name attribute
belongs_to :foo
end
This definition gives me the possibility to create Foo with many Larodi's just by giving a hash of parameters. For example:
x = Foo.create(name: 'Josh', larodi_attributes: [ {name: 'Wayne'} ]
x.larodis.map(&:name) # ['Wayne']
Now comes the part where #field_for understands if we have nested attribute to work with. We check this by looking for name_attributes= method. If it is defined #fields_for generates form of the type <input ... name=object[name][INDEX][method]>... where index is just an integer.
Keep in mind that when implementing custom name_attibutes(attributes) you must check attributes type - it can be Array like the example, it can be Hash of this type:
{ 1 => { ... } , 2 => { ... } }
Just like a hash representing array, where the key is index and value is the value for this index.
The answear looks like this:
_form.html.haml
....
= crawler_form.fields_for :entry_pages do |entry_page_field|
%li
=entry_page_field.text_field :url, size: 80
...
company_crawler.rb
class CompanyCrawler < ActiveRecord::Base
....
serialize :entry_pages, Array
def entry_pages_attributes=(attributes)
self.entry_pages = attributes_collection(attributes).map do |attribute|
EntryPage.new(attribute[:url])
end
end
def entry_pages=(entry_pages)
entry_pages = entry_pages.map do |entry_page|
cast_entry_page_to_entry_page_object(entry_page)
end
write_attribute(:entry_pages, entry_pages)
end
...
private
def attributes_collection(attributes)
case attributes
when Array
attributes
when Hash
attributes.values
end
end
def cast_entry_page_to_entry_page_object(entry_page)
case entry_page
when String
EntryPage.new(entry_page)
when EntryPage
entry_page
end
end
end
For clarity I have removed entry_page_objects and use only entry_pages.
I'm creating a Sinatra App using Datamapper.
With the following route, I'm attempting to print the record for an id. So localhost:9292/api/1 should return results for id=1
inside
get '/api/:id' do
I tried a couple things with varied results:
thing = Thing.get(params[:id])
thing.to_json
end
outputs 'null', but:
id_param = params[:id]
id_param
end
prints 1 as expected, and:
hardcoded_thing = Thing.get(1)
hardcoded_thing.to_json
end
correctly prints the hardcoded db record with id=1. So I must be losing it..
Any ideas?
Thanks!
For reference, here's my model:
class Thing
include DataMapper::Resource
include BCrypt
property :id, Serial, :key => true
property :created_at, DateTime
property :updated_at, DateTime
property :name, String, :length => 50
property :cafe_topic, Text
end
Try this:
get '/api/:id' do |id|
thing = Thing.get(id)
thing.to_json
end
I have a relational DB defined as follows. How can I enter a new value, where B belongs to A. The code given below doesn't seem to work.
Thanks
class A
include DataMapper::Resource
property :id, Serial, :key => true
property :name, String
belongs_to :b
end
class B
include DataMapper::Resource
property :id, Serial, :key => true
property :name, String
has n, :as
end
Create new value
# Create new value
post '/create' do
a = A.new
b = B.new
b.attributes = params
b.belongs_to = a #problem is here
b.save
redirect("/info/#{a.id}")
end
#belongs_to is a model (class) method and you use it to declare ManyToOne relationship.
In your example you should use "<<" method like this:
b.as << a
That will add "a" instance to "as" collection and associate both resources.
[...] How can I enter a new value, where B belongs to A. The code given below doesn't seem to work.
Your code implies you're after A belonging to B, but your question is the reverse so I'll show how to do that, i.e., B belongs to A.
class A
include DataMapper::Resource
property :id, Serial, :key => true
property :name, String
has n, :bs # A has many B's
end
class B
include DataMapper::Resource
property :id, Serial, :key => true
property :name, String
belongs_to :a, :required => false # B has only 1 A
end
Note your has and belongs_to are reversed here. I also added required => false to the belongs_to side because DataMapper will silently refuse to save your model if ever don't have b.a before calling save—once you're comfortable with it you can remove the required false if you desire.
Here are two ways you can use that model:
# Create new value
post '/create' do
a = A.new
a.save
b = B.new
b.attributes = params
b.a = a
b.save
redirect("/info/#{a.id}")
end
This example is generally the same as yours, but I added a save call for A. Note this may not be necessary, I'm not in a good place to test this particular case; in the past I've found DataMapper will save some related objects automatically but not others so I've developed the habit of always saving explicitly to prevent confusion.
# Create new value
post '/create' do
a = A.create
b = a.bs.create(params)
redirect("/info/#{a.id}")
end
In the second example I call create on the many-side of the relationship, this makes a new B, associates it with "a", sets the params given, and saves it immediately. The result is the same as the previous example.
If you're just getting familiar with DataMapper, you may find it helpful to add the following to your app:
DataMapper::Model.raise_on_save_failure = true
This will cause DataMapper to give you errors and backtraces in cases like the above, more info here.
When I try to modify and then save a model using DataMapper I get a SaveFailure exception but no errors.
Specifically I see this message:
"MonthlyBill#save returned false, MonthlyBill was not saved"
This is the code doing the saving:
post '/monthly_bills' do
with_authenticated_user do |user|
description = params[:description]
expected_amount = params[:expected_amount]
pay_period = params[:pay_period]
monthly_bill = MonthlyBill.new(:description=>description, :expected_amount=>expected_amount, :pay_period=>pay_period)
user.monthly_bills << monthly_bill
user.save
end
The User model:
class User
include DataMapper::Resource
property :id, Serial
property :email_address, String
property :password, String
has n, :monthly_bills
has 1, :current_pay_period
end
The MonthlyBill model:
class MonthlyBill
include DataMapper::Resource
property :id, Serial
property :description, String
property :expected_amount,Decimal
property :pay_period, Integer
belongs_to :user
end
What is the issue and, more importantly, how can I get DataMapper to tell me more specifically what is wrong?
Hmm - those capitalised properties look worrying to me. I would do...
has n, :monthly_bills
has 1, :current_pay_period #do you really have a CurrentPayPeriod model?!
And then try:
monthly_bill = MonthlyBill.new(:description=>description,:expected_amount=>expected_amount, :pay_period=>pay_period, :user=>user)
monthly_bill.save