Aims to provide a declarative JSON based mapper
run irb -r ./dev/setup for an interactive prompt.
Add this line to your application's Gemfile:
gem 'json-path-builder'And then execute:
$ bundle install
Or install it yourself as:
$ gem install json-path-builder
maps input based fields to be mapped via
.frommethod
For advance usage check out .from documentation
input = { key: "some-value" }
JsonPath::Builder.new.from(:key, to: :another_key).build_for(input)
#=> {:another_key=>"some-value"}defines the json path(s) to locate the value(s) to be mapped for each field
json_path~ JSON path supporting dot notation which contains the value(s) relating to the field to be mapped e.g.account.profile.name
to:~ field name for mapped value (defaults tojson_path)transform:- can be one of the following
Proce.g.->(val) { val.to_s.upcase }to convert value located atjson_pathto uppercase- Built in Transforms
:iso8601e.g.Date.new(2022,1,1)=>2022-01-01:datee.g.2022-01-01=><Date Sat, 01 Jan 2022>
defaults- (Hash) e.g.{user_id: 1}fallback- (Proc) used when mapped value isblank
- can be one of the following
Example:
# Example 1 - Mapping subset of fields
input = { key: "some-value", other_key: "some-other-value", list: %w[some-list-value-1 some-list-value-2] }.as_json
builder = JsonPath::Builder.new
builder.from(:key)
builder.from(:other_key)
builder.build_for(input) #=> {:key=>"some-value", :other_key=>"some-other-value"}
# Example 2 - Mapping nested field to non nested
input = { profile: {email: '[email protected]'} }.as_json
JsonPath::Builder.new.from('profile.email', to: :email).build_for(input) #=> {:email=>"[email protected]"}
# Example 3 - mapping field to another field name
input = { key: "some-value" }
JsonPath::Builder.new.from(:key, to: :another_key).build_for(input) #=> {:another_key=>"some-value"}
# Example 4 - mapping field to nested field
input = { key: "some-value" }
JsonPath::Builder.new.from(:key, to: "root.key").build_for(input) #=> {:root=>{:key=>"some-value"}}
# Example 5 - transforming value to uppercase
input = { key: "some-value" }
transform = ->(val) { val.to_s.upcase }
JsonPath::Builder.new.from(:key, transform: transform).build_for(input) #=> {:key=>"SOME-VALUE"}
# Example 6 - transforming value to iso8601 format
input = { created_at: Date.new(2022,1,2) }
transform = :iso8601
JsonPath::Builder.new.from(:created_at, transform: transform).build_for(input) #=> {:created_at=>"2022-01-02"}
# Example 6 - transforming value to iso8601 format
input = { created_at: '2023-02-27 16:24:02' }
transform = :date
JsonPath::Builder.new.from(:created_at, transform: transform).build_for(input) #=> {:created_at=><Date Sat, 01 Jan 2022>}
# Example 7 - fallback when value to be mapped is `nil` or not present
input = { }
fallback = -> { Time.now }
JsonPath::Builder.new.from(:created_at, fallback: fallback).build_for(input)
# => {:created_at=> <Time 2023-02-27 16:36:44.068037 -0700>}similar to
.frombut for mapping list items
Example:
input = { list: %w[some-list-value-1 some-list-value-2] }.as_json
builder = JsonPath::Builder.new
transform = proc { |val| val.upcase }
builder.from_each(:list, to: :keys, transform: transform)
builder.build_for(input) #=> {:keys=>["SOME-LIST-VALUE-1", "SOME-LIST-VALUE-2"]}Adds the ability to provide a scope based on dot notation
Example:
input = { root: { deep: { profile: { email: '[email protected]', uid: 1 } } } }.as_json
builder = JsonPath::Builder.new
builder.within('root.deep.profile') do |b|
b.from(:email)
b.from(:uid, to: :user_id)
end
builder.build_for(input) #=> {:email=>"[email protected]", :user_id=>1}Supports wrapping mapped values with a custom class that must act like a hash i.e. implements
SimpleDelegator
Example:
input = { profile: { email: '[email protected]', uid: 1 } }.as_json
builder = JsonPath::Builder.new
wrapped_data_class = Class.new(SimpleDelegator) do
def user
User.find_by(email: self[:email])
end
end
builder.with_wrapped_data_class(wrapped_data_class)
transform = proc { |email, path_context| }
builder.from('profile.email', to: :user_id, transform: transform)
email = '[email protected]'
user_id = 123
input = { profile: { email: email } }.as_json
user = OpenStruct.new(id: user_id)
user_repo = OpenStruct.new(find_by: -> (_email) { user })
wrapped_data_class = Class.new(SimpleDelegator) do
class << self
attr_accessor :user_repo
end
def user
self.class.user_repo.find_by.call(email: self.dig('profile', 'email'))
end
end
wrapped_data_class.user_repo = user_repo
builder = JsonPath::Builder.new
builder.with_wrapped_data_class(wrapped_data_class)
transform = proc do |_email, path_context|
path_context.wrapped_source_data.user.id
end
builder.from('profile.email', to: :user_id, transform: transform)
builder.build_for(input) #=> {:user_id=>123}After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/json-path-builder. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.
The gem is available as open source under the terms of the MIT License.
Everyone interacting in the JsonPathBuilder project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.