I am setting up an API.
The client (using HTTParty) posts this to the API:
{:body =>
{
:product=> {:description=>"some text", :cost => "11.99"},
:brand=> {:name=>"BrandName", :etc =>"hey"}
}
}
The server/api receives the post.
Now, if I access params[:brand] I get:
{"name"=>"BrandName", "etc" =>"hey"}
If I do this:
Brand.new(params[:brand])
Then I get a new Brand object with the "name" and "etc" attributes populated correctly.
However, if I try to access params[:brand][:name], I just get nil
Any ideas?
Thanks.
Use params[:brand]["name"] or params["brand"]["name"]
Hash keys can be any sort of object. Common rails practice is to use symbols as hash keys, but when translated from JSON, the keys are likely to be strings.
Related
I'm using Toptal's Chewy gem to connect and query my Elasticsearch, just like an ODM.
I'm using Chewy along with Elasticsearch 6, Ruby on Rails 5.2 and Active Record.
I've defined my index just like this:
class OrdersIndex < Chewy::Index
define_type Order.includes(:customer) do
field :id, type: "keyword"
field :customer do
field :id, type: "keyword"
field :name, type: "text"
field :email, type: "keyword"
end
end
end
And my model:
class Order < ApplicationRecord
belongs_to :customer
end
The problem here is that when I perform any query using Chewy, the customer data gets deserialized as a hash instead of an Object, and I can't use the dot notation to access the nested data.
results = OrdersIndex.query(query_string: { query: "test" })
results.first.id
# => "594d8e8b2cc640bb78bd115ae644637a1cc84dd460be6f69"
results.first.customer.name
# => NoMethodError: undefined method `name' for #<Hash:0x000000000931d928>
results.first.customer["name"]
# => "Frederique Schaefer"
How can I access the nested association using the dot notation (result.customer.name)? Or to deserialize the nested data inside an Object such as a Struct, that allows me to use the dot notation?
try to use
results = OrdersIndex.query(query_string: { query: "test" }).objects
It converts query result into active record Objects. so dot notation should work. If you want to load any extra association with the above result you can use .load method on Index.
If you want to convert existing ES nested object to accessible with dot notation try to reference this answer. Open Struct is best way to get things done in ruby.
Unable to use dot syntax for ruby hash
also, this one can help too
see this link if you need openStruct to work for nested object
Converting the just-deserialized results to JSON string and deserializing it again with OpenStruct as an object_class can be a bad idea and has a great CPU cost.
I've solved it differently, using recursion and the Ruby's native Struct, preserving the laziness of the Chewy gem.
def convert_to_object(keys, values)
schema = Struct.new(*keys.map(&:to_sym))
object = schema.new(*values)
object.each_pair do |key, value|
if value.is_a?(Hash)
object.send("#{key}=", convert_to_object(value.keys, value.values))
end
end
object
end
OrdersIndex.query(query_string: { query: "test" }).lazy.map do |item|
convert_to_object(item.attributes.keys, item.attributes.values)
end
convert_to_object takes an array of keys and another one of values and creates a struct from it. Whenever the class of one of the array of values items is a Hash, then it converts to a struct, recursively, passing the hash keys and values.
To presence the laziness, that is the coolest part of Chewy, I've used Enumerator::Lazy and Enumerator#map. Mapping every value returned by the ES query into the convert_to_object function, makes every entry a complete struct.
The code is very generic and works to every index I've got.
I receive (similar to) the following JSON data:
{"accountId"=>"some-private-really-long-account-id",
"stats"=>
{"score"=>
{"globalScore"=>
[{"key"=>"lifetimeScore", "value"=>"571",
"key"=>"someOtherKeyHere", "value"=>"someValue"}]}
I am not quite sure how I would get the lifetime score. I've tried doing stuff like this:
puts data["globalScore"]["lifetimeScore"]["value"]
But that doesn't work. (data is of course the JSON data received).
I believe the problem here is that data["globalScore"]["lifetimeScore"]["value"] doesn't reference a valid "path" within the JSON. Better formatting helps to clarify this:
hash = {
"accountId" => "some-private-really-long-account-id",
"stats" => {
"score" => {
"globalScore" => [
{
"key" => "lifetimeScore",
"value" => "571",
"key" => "someOtherKeyHere",
"value" => "someValue"
}
]
}
}
}
This Ruby hash has some issues since a hash can't actually have multiple values for a given key, but that aside,
hash['stats']['score']['globalScore'][0]['value']
is a perfectly valid way to access the 'value' field.
My point is that the problem with the original question is not that hash#dig(...) should be used (as shown by #Phlip), it is that the "path" through the Hash data structure was actually invalid.
hash.dig("globalScore", "lifetimeScore", "value)
will fail just like the bracketed syntax in the original question.
Use JSON.parse(body) to convert your json to a hash. Then use hash.dig('stats', 'score', 'globalScore', 0, 'value') to run queries on that hash.
So I am iterating through a set of data and building a hash from it:
clean_response = Array.new
response.each_with_index do |h, idx|
clean_response <<
{
:lat => h["location"]["latitude"],
:lg => h["location"]["longitude"],
:place => h["location"]["name"],
#This grabs the entire hash at "location" because we are wanting all of that data
:profile_picture => h["user"]["profile_picture"],
:hash_tags => h["tags"],
:username => h["user"]["username"],
:fullname => h["user"]["full_name"],
:created_time => (Time.at(h["created_time"].to_i)).to_s,
:image => h["images"]["low_resolution"]["url"] # we can replace this with whichever resolution.
}
end
Which return an array of hashes like so:
[{:lat=>40.7486382,
:lg=>-73.9487686,
:place=>"The Cliffs at LIC",
:profile_picture=>"http://scontent.cdninstagram.com/hphotos-xaf1/t51.2885-19/s150x150/12104940_1653775014895036_286845624_a.jpg",
:hash_tags=>["bouldering"],
:username=>"denim_climber",
:fullname=>"DenimClimber",
:created_time=>2015-10-13 22:58:09 -0400,
:image=>"https://scontent.cdninstagram.com/hphotos-xaf1/t51.2885-15/s320x320/e35/11856571_1062082890510188_611068928_n.jpg"},
{:lat=>40.7459602,
:lg=>-73.9574966,
:place=>"SHI",
:profile_picture=>"http://scontent.cdninstagram.com/hphotos-xaf1/t51.2885-19/11348212_1453525204954535_631200718_a.jpg",
:hash_tags=>["cousins", "suchafunmoment", "johnlennonstyle"],
:username=>"xiomirb",
:fullname=>"Xiomi",
:created_time=>2015-10-13 22:57:21 -0400,
:image=>"https://scontent.cdninstagram.com/hphotos-xaf1/t51.2885-15/s320x320/e35/11375290_1688934151392424_2009781937_n.jpg"}]
I'd like to convert this data to json and then serve it to a specific view.
How can I convert this? I tried the .to_json method but it doesn't return a well formatted one since my UI isn't binding to the data.
You can convert a Ruby hash into JSON using to_json:
require 'json'
your_hash.to_json # gives you a JSON object
But, in your case the data is an array of hashes, but NOT a hash. So, your to_json would not work.
I am not quite sure how you want to do this, but one possibility is to loop through the array of hashes, get each hash and convert that to a JSON object using to_json call (like shown above) and build a new array of JSON objects. This way, you can build an array of JSON objects from an array of hashes.
array_of_json = []
# loop through the array of hashes
clean_response.each do |hash|
array_of_json << hash.to_json
end
array_of_json # array of JSON objects
If by "serve it to a specific view" you mean pass it to a .haml or .erb template, you can pass the array of hashes as is. Both haml and erb will allow you to iterate over the array, and even the hash if you want.
If you mean you want to hand a json string to the browser, #to_json should work fine. Other options are jbuilder or oat when you want to refine what is sent, but to_json should "serve" you well!
I have a Model that is called teams.
When I do Teams.account_ids it returns something like:
[{"_id"=>"145952912234658", "_type"=>"Page"},
{"_id"=>"465641870160985", "_type"=>"Account"}]
Lets say I want to get all Teams that have one specific account id regardless of its _type.
Something like:
Team.where(some_id.in => account_ids.map{|k| k["_id"))
You can use multi-keys to effectively ignore the array when searching and then use the standard "key inside a hash" notation to look at the _ids:
Teams.where('account_ids._id' => { :$in => array_of_ids })
I am having problems accessing the attributes of my JSON data. Instead of accessing the JSON data it thinks it is a function.
#response = HTTParty.get('http://localhost:4000/test')
#json = JSON.parse(#response.body)
#json.each do |pet|
MyModel.create(pet) ! WORKS
puts "my object #{pet}" ! WORKS
puts "my object attribute #{pet.myattribute}" ! DOES NOT WORK
end
With no MethodError myattribute.
Thank you for any help!
You may be used to JavaScript, where both object.some_key and object["some_key"] do the same thing. In Ruby, a hash is just a hash, so you have to access values via object["some_key"]. A Struct in Ruby is similar to a JavaScript object, in that you can access values both ways, but the keys have to be pre-defined.
#json = JSON.parse(#response.body) returns a hash, so you would need to do
puts "my object attributes #{pet['id']}, #{pet['title']}"
you might want to convert to HashWithIndifferentAccess so you can use symbols instead of quoted strings, i.e.
#json = JSON.parse(#response.body).with_indifferent_access
# ...
puts "my object attributes #{pet[:id]}, #{pet[:title]}"