Here's what's happend: I have gone and pulled a large amount of data from an API. This is nice, but it includes a lot of results.
When I do a result.find(id: api_id) I get all the results like find was never performed. #where does not work either. I'm assuming this is because its not extending from Active Model.
Key Question: How do I find, say, the name of a particular object in an active resource collection?
Object.find(id: api_id) in active resource is essentially doing an api request as in (uri_of_api)/objects/:api_id)
But the :find method on an array is a different aninmal. You can look up the array 'find' method here... http://www.ruby-doc.org/core-2.1.1/Enumerable.html#method-i-find
The correct format would be...
result.find{|rec| rec.id == api_id}
Related
I want to write a test on helper method which fetches data from external service based on an id. So there is an uncertainty whether the value will be returned or nil. But if value is returned, id of returned value must be equal to given id. Is there a way to achieve this?
expect(record).to be_nil.or expect(record.id).to eq(deal.user_id)
however it seems the or condition does not work the way I think. I am new to RoR. Might be missing any obvious way to do it.
You can write ruby code in specs too:
if record != nil
expect(record.id).to eq(deal.user_id)
end
or combine matchers:
expect(record).to be_nil.or(eq(deal.user_id))
I'm not sure if this is just a lacking of the Rails language, or if I am searching all the wrong things here on Stack Overflow, but I cannot find out how to add an attribute to each record in an array.
Here is an example of what I'm trying to do:
#news_stories.each do |individual_news_story|
#user_for_record = User.where(:id => individual_news_story[:user_id]).pluck('name', 'profile_image_url');
individual_news_story.attributes(:author_name) = #user_for_record[0][0]
individual_news_story.attributes(:author_avatar) = #user_for_record[0][1]
end
Any ideas?
If the NewsStory model (or whatever its name is) has a belongs_to relationship to User, then you don't have to do any of this. You can access the attributes of the associated User directly:
#news_stories.each do |news_story|
news_story.user.name # gives you the name of the associated user
news_story.user.profile_image_url # same for the avatar
end
To avoid an N+1 query, you can preload the associated user record for every news story at once by using includes in the NewsStory query:
NewsStory.includes(:user)... # rest of the query
If you do this, you won't need the #user_for_record query — Rails will do the heavy lifting for you, and you could even see a performance improvement, thanks to not issuing a separate pluck query for every single news story in the collection.
If you need to have those extra attributes there regardless:
You can select them as extra attributes in your NewsStory query:
NewsStory.
includes(:user).
joins(:user).
select([
NewsStory.arel_table[Arel.star],
User.arel_table[:name].as("author_name"),
User.arel_table[:profile_image_url].as("author_avatar"),
]).
where(...) # rest of the query
It looks like you're trying to cache the name and avatar of the user on the NewsStory model, in which case, what you want is this:
#news_stories.each do |individual_news_story|
user_for_record = User.find(individual_news_story.user_id)
individual_news_story.author_name = user_for_record.name
individual_news_story.author_avatar = user_for_record.profile_image_url
end
A couple of notes.
I've used find instead of where. find returns a single record identified by it's primary key (id); where returns an array of records. There are definitely more efficient ways to do this -- eager-loading, for one -- but since you're just starting out, I think it's more important to learn the basics before you dig into the advanced stuff to make things more performant.
I've gotten rid of the pluck call, because here again, you're just learning and pluck is a performance optimization useful when you're working with large amounts of data, and if that's what you're doing then activerecord has a batch api you should look into.
I've changed #user_for_record to user_for_record. The # denote instance variables in ruby. Instance variables are shared and accessible from any instance method in an instance of a class. In this case, all you need is a local variable.
In my rails app I have a collectionproxy that is an array (I think) of records. I want to take a record from the middle of the array and put it at the beginning. I don't know the position of the item, but I can find it using an attribute on user model. It seems like some methods aren't available to use on a collectionproxy.
I tried:
user_images = user.images
user_images.insert(0, user_images.delete(user.images.find_by_id(user.primary_image_id))
but got an error that I gave 2 arguments but it expected 1. I'm guessing because the insert method that is used on arrays isnt the same method that is used on collectionproxies. What's the best way to do this?
Edit: I just need this to display the items in the view, I don't need to change at the database level.
As very few methods are available for collection proxy, first change the collection proxy to array and then manipulate it.
Here is the code to do so,
user_images = user.images.to_a //converted collection to array
user_images.unshift(user_images.detect{ |image| image.id == user.primary_image_id}).uniq //used unshift
puts user_images
The magic we have done here is detect the images that's the primary image of the user and unshift into array
The unshift adds the object in the beginning.
Now remove the duplicated oject which is already there at someplace by using uniq.
That's it your required objects comes first into the array and you can use this in the view as active record collection is used.
It looks like there's currently no way to add to the beginning of a CollectionProxy. The prepend and sort methods were removed. Here's the API for the deprecated prepend method:
http://apidock.com/rails/v4.2.1/ActiveRecord/Associations/CollectionProxy/prepend
You could re-think this slightly, and use the append or << operator along with delete to copy elements to the end of the collection, and delete them from the middle. It's not ideal, but it might be a workaround until you have a better solution.
I'm working on implementing a search form in a ruby on rails application. The general idea is to use form_tag to submit the search fields (via params) to a search function in the model of the class I'm trying to search. The search function will then iterate through each of the params and execute a scoping function if the name of the function appears in params.
The issue is that when I call the search on a collection like so:
#calendar.reservations.search({:search_email => "test"})
I don't know how to refer to the collection of #calendar.reservations from within the search function.
Additionally I'm confused as to why #calendar.reservations.search(...) works, but Reservations.all.search gives me an error saying you can't call an instance method on an array.
I've got the details of the search method over here: https://gist.github.com/783964
Any help would be greatly appreciated!
I don't know how to refer to the
collection of #calendar.reservations
from within the search function.
If you use self (or Reservation, it's the same object) inside the classmethod, you will access the records with the current scope, so in your case you will see only the reservations of a particular calendar.
[edit] I looked at you search function, and I think what you want is:
def self.search(search_fields)
search_fields.inject(self) do |scope, (key, value)|
scope.send(key, value)
end
end
Additionally I'm confused as to why
#calendar.reservations.search(...)
works, but Reservations.all.search
gives me an error saying you can't
call an instance method on an array.
#calendar.reservations does not return a standard array but a (lazy) AssociationCollection, where you can still apply scopes (and classmethods as your filter). On the other hand Reservation.all returns a plain array, so you cannot execute search there (or any scope, for that matter).
You don't really need a search method at all, as far as I can tell.
Simply use where:
#calendar.reservations.where(:search_email => 'test')
I would strongly encourage you to look at the MetaSearch GEM by Ernie Miller. It handles the kind of thing you're working on very elegantly and is quite easy to implement. I suspect that your view code would almost accomplish what the GEM needs already, and this would take care of all your model searching needs very nicely.
Take a look and see if it will solve your problem. Good luck!
Reservation.all.search doesn't work because it returns all the results as an array, while Reservation.where(..) returns an ActiveRecord object (AREL). Reservation.all actually fetches the results instead of just building the query further, which methods like where, limit etc do.
I'm accessing the Amazon AWS API using the ruby-aaws gem, but without going to much into details of the API or the gem, I think my problem is more of a general nature.
When I query the API I will end up with "object array", let's call it item, containing the API response.
I can easily access the data in the array, e.g. puts item.item_attributes.artist.to_s
Now the API returns attributes whose identifier are reserved words in Rails, e.g. format or binding.
So doing this:
puts item.item_attributes.format.to_s will return method not found
while
puts item.item_attributes.binding.to_s will return some object hash like #<Binding:0xb70478e4>.
I can see that there are values under that name when doing
puts item.item_attributes.to_yaml
Snippet from the resulting yaml show artist and binding:
--- !seq:Amazon::AWS::AWSArray
- !ruby/object:Amazon::AWS::AWSObject::ItemAttributes
__val__:
artist: !seq:Amazon::AWS::AWSArray
- !ruby/object:Amazon::AWS::AWSObject::Artist
__val__: Summerbirds in the Cellar
binding: !seq:Amazon::AWS::AWSArray
- !ruby/object:Amazon::AWS::AWSObject::Binding
__val__: Vinyl
This was probably a very detailed explanation with a very simple solution, but I can't seem to find the solution.
edit
Finally found it. I guess it is because it is an array of objects, duh...
puts item.item_attributes[0].binding.to_s
You may be able to access the individual attributes by using [] instead of the method name (which is probably provided using method_missing anyway).
So, item.item_attributes[:artist].to_s may return what you want. If it doesn't it would be worth trying 'artist' as the key instead.
Finally found it. I guess it is because it is an array of objects, duh...
puts item.item_attributes[0].binding.to_s