Accessing hashes with slash separated keys - ruby-on-rails

Question

Suppose I have the following hash in one of my models named Company.
FIELDS = {
TEAM: {
'num_founders': 'Number of Founders',
'num_employees': 'Number of Employees',
'founders': {
'person_info': {
'full_name': 'Full Name',
'first_name': 'First Name',
'last_name': 'Last Name',
'location': 'Location',
'gender': 'Gender',
'biography': 'Biography',
'num_articles': 'Number of Articles'
}
}
}
}
And I have a action in my application controller which renders this hash as json:
def field_names
module_name = params[:module]
category = params[:category]
case module_name
when 'company'
render json: Company::FIELDS[category.to_sym].to_json
end
end
So now if I open localhost:3000/field_names/company/TEAM I'd get the json. But the problem I'm now facing is I need to get the sub hash of this hash too. Like I want to /field_names/company/TEAM/founders/person_info and get the respective object.
To begin with I'd split the url by slashes to get the keys. Im unable to figure out how would I use those strings to access the hash.
If I define the route like get '/field_names/:query', to: 'application#field_names
And If I hit localhost:3000/field_names/company/TEAM/founders
The action should render Company::FIELDS[:TEAM]["founders"] object which would be
'person_info': {
'full_name': 'Full Name',
'first_name': 'First Name',
'last_name': 'Last Name',
'location': 'Location',
'gender': 'Gender',
'biography': 'Biography',
'num_articles': 'Number of Articles'
}
For this my action should do something like:
def field_names
query = params[:query]
keys = query.split("/")
#keys.first::FIELDS[key2][key3]... .to_json
end
How do I achieve this? Thanks :)

Answer 1

How about something like this:
fields = {
TEAM: {
'num_founders': 'Number of Founders',
'num_employees': 'Number of Employees',
'founders': {
'person_info': {
'full_name': 'Full Name',
'first_name': 'First Name',
'last_name': 'Last Name',
'location': 'Location',
'gender': 'Gender',
'biography': 'Biography',
'num_articles': 'Number of Articles'
}
}
}
}.with_indifferent_access
'TEAM/founders'.split('/').each do |key|
fields = fields[key]
end
puts fields
=> {"person_info"=>{"full_name"=>"Full Name", "first_name"=>"First Name", "last_name"=>"Last Name", "location"=>"Location", "gender"=>"Gender", "biography"=>"Biography", "num_articles"=>"Number of Articles"}}
Just for console, I changed FIELDS to fields (SHOUTING_CASE is usually reserved for constants, fwiw). And, I used with_indifferent_access because your nested hashes use both strings and symbols as keys.
If you want that person_info, then:
fields = {
TEAM: {
'num_founders': 'Number of Founders',
'num_employees': 'Number of Employees',
'founders': {
'person_info': {
'full_name': 'Full Name',
'first_name': 'First Name',
'last_name': 'Last Name',
'location': 'Location',
'gender': 'Gender',
'biography': 'Biography',
'num_articles': 'Number of Articles'
}
}
}
}.with_indifferent_access
'TEAM/founders/person_info'.split('/').each do |key|
fields = fields[key]
end
puts fields
=> {"full_name"=>"Full Name", "first_name"=>"First Name", "last_name"=>"Last Name", "location"=>"Location", "gender"=>"Gender", "biography"=>"Biography", "num_articles"=>"Number of Articles"}
You probably want to put some try in there in case the url is malformed.
Also, you could abstract and simplify that bit where you go:
case module_name
when 'company'
render json: Company::FIELDS[category.to_sym].to_json
end
Assuming you have (in routes.rb):
get '/field_names/:query'
And you hit:
localhost:3000/field_names/company/TEAM/founders
Then your params should include:
{query: 'company/TEAM/founders'}
In which case you do something like:
def field_names
query_split = params[:query].split
module_name = query_split.shift.camelize
fields = "#{module_name}::FIELDS".constantize.clone.with_indifferent_access
query_split.each{|key| fields = fields[key]}
render json: fields
end
You don't have to put to_json at the end of your hash, btw.

Answer 2

It's a routing problem in your project. Actually, you should have a route to retrieve these fieldnames, like:
get 'field_names' => 'controller#action'
then, you can pass any parameters on your URL.
Eg.
/field_names?company=TEAM&attribute=founders
Than, those attributes would be available in your controller as
params[:company]
params[:attribute]
and so you can render only the attributes you want