Merge pull request #1674 from glaucocustodio/implement-as

Add parameter alias

Author: dblock

CHANGELOG.md

@@ -5,6 +5,7 @@
 * Your contribution here.
 * [#1652](https://github.com/ruby-grape/grape/pull/1652): Add the original exception to the error_formatter the original exception - [@dcsg](https://github.com/dcsg).
 * [#1665](https://github.com/ruby-grape/grape/pull/1665): Make helpers available in subclasses - [@pablonahuelgomez](https://github.com/pablonahuelgomez).
+* [#1674](https://github.com/ruby-grape/grape/pull/1674): Add parameter alias (`as`) - [@glaucocustodio](https://github.com/glaucocustodio).
 
 #### Fixes
 

README.md

@@ -42,6 +42,7 @@
   - [Validation of Nested Parameters](#validation-of-nested-parameters)
   - [Dependent Parameters](#dependent-parameters)
   - [Group Options](#group-options)
+  - [Alias](#alias)
   - [Built-in Validators](#built-in-validators)
   - [Namespace Validation and Coercion](#namespace-validation-and-coercion)
   - [Custom Validators](#custom-validators)
@@ -1094,6 +1095,23 @@ params do
 end
 ```
 
+### Alias
+
+You can set an alias for parameters using `as`, which can be useful when refactoring existing APIs:
+
+```ruby
+resource :users do
+  params do
+    requires :email_address, as: :email
+    requires :password
+  end
+  post do
+    User.create!(declared(params)) # User takes email and password
+  end
+end
+```
+
+The value passed to `as` will be the key when calling `params` or `declared(params)`.
 
 ### Built-in Validators
 

lib/grape.rb

@@ -13,6 +13,7 @@
 require 'active_support/core_ext/hash/deep_merge'
 require 'active_support/core_ext/hash/reverse_merge'
 require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/hash/slice'
 require 'active_support/core_ext/hash/conversions'
 require 'active_support/dependencies/autoload'
 require 'active_support/notifications'
@@ -198,6 +199,7 @@ module ServeFile
 require 'grape/validations/validators/base'
 require 'grape/validations/attributes_iterator'
 require 'grape/validations/validators/allow_blank'
+require 'grape/validations/validators/as'
 require 'grape/validations/validators/at_least_one_of'
 require 'grape/validations/validators/coerce'
 require 'grape/validations/validators/default'

lib/grape/dsl/inside_route.rb

@@ -50,8 +50,16 @@ def declared_hash(passed_params, options, declared_params)
             # If it is not a Hash then it does not have children.
             # Find its value or set it to nil.
             if !declared_param.is_a?(Hash)
-              next unless options[:include_missing] || passed_params.key?(declared_param)
-              memo[optioned_param_key(declared_param, options)] = passed_params[declared_param]
+              has_alias = route_setting(:aliased_params) && route_setting(:aliased_params).find { |current| current[declared_param] }
+              param_alias = has_alias[declared_param] if has_alias
+
+              next unless options[:include_missing] || passed_params.key?(declared_param) || param_alias
+
+              if param_alias
+                memo[optioned_param_key(param_alias, options)] = passed_params[param_alias]
+              else
+                memo[optioned_param_key(declared_param, options)] = passed_params[declared_param]
+              end
             else
               declared_param.each_pair do |declared_parent_param, declared_children_params|
                 next unless options[:include_missing] || passed_params.key?(declared_parent_param)

lib/grape/dsl/parameters.rb

@@ -131,8 +131,7 @@ def requires(*attrs, &block)
           require_required_and_optional_fields(attrs.first, opts)
         else
           validate_attributes(attrs, opts, &block)
-
-          block_given? ? new_scope(orig_attrs, &block) : push_declared_params(attrs)
+          block_given? ? new_scope(orig_attrs, &block) : push_declared_params(attrs, opts.slice(:as))
         end
       end
 
@@ -158,7 +157,7 @@ def optional(*attrs, &block)
         else
           validate_attributes(attrs, opts, &block)
 
-          block_given? ? new_scope(orig_attrs, true, &block) : push_declared_params(attrs)
+          block_given? ? new_scope(orig_attrs, true, &block) : push_declared_params(attrs, opts.slice(:as))
         end
       end
 

lib/grape/validations/params_scope.rb

@@ -115,10 +115,15 @@ def required?
 
       # Adds a parameter declaration to our list of validations.
       # @param attrs [Array] (see Grape::DSL::Parameters#requires)
-      def push_declared_params(attrs)
+      def push_declared_params(attrs, **opts)
         if lateral?
           @parent.push_declared_params(attrs)
         else
+          if opts && opts[:as]
+            @api.route_setting(:aliased_params, @api.route_setting(:aliased_params) || [])
+            @api.route_setting(:aliased_params) << { attrs.first => opts[:as] }
+          end
+
           @declared_params.concat attrs
         end
       end

lib/grape/validations/validators/as.rb

@@ -0,0 +1,15 @@
+module Grape
+  module Validations
+    class AsValidator < Base
+      def initialize(attrs, options, required, scope, opts = {})
+        @alias = options
+        super
+      end
+
+      def validate_param!(attr_name, params)
+        params[@alias] = params[attr_name]
+        params.delete(attr_name)
+      end
+    end
+  end
+end

spec/grape/dsl/parameters_spec.rb

@@ -15,7 +15,7 @@ def validate_attributes_reader
           @validate_attributes
         end
 
-        def push_declared_params(*args)
+        def push_declared_params(args, **_opts)
           @push_declared_params = args
         end
 
@@ -84,7 +84,7 @@ def extract_message_option(attrs)
           subject.requires :id, type: Integer, desc: 'Identity.'
 
           expect(subject.validate_attributes_reader).to eq([[:id], { type: Integer, desc: 'Identity.', presence: { value: true, message: nil } }])
-          expect(subject.push_declared_params_reader).to eq([[:id]])
+          expect(subject.push_declared_params_reader).to eq([:id])
         end
       end
 
@@ -93,7 +93,7 @@ def extract_message_option(attrs)
           subject.optional :id, type: Integer, desc: 'Identity.'
 
           expect(subject.validate_attributes_reader).to eq([[:id], { type: Integer, desc: 'Identity.' }])
-          expect(subject.push_declared_params_reader).to eq([[:id]])
+          expect(subject.push_declared_params_reader).to eq([:id])
         end
       end
 
@@ -102,7 +102,7 @@ def extract_message_option(attrs)
           subject.with(type: Integer) { subject.optional :id, desc: 'Identity.' }
 
           expect(subject.validate_attributes_reader).to eq([[:id], { type: Integer, desc: 'Identity.' }])
-          expect(subject.push_declared_params_reader).to eq([[:id]])
+          expect(subject.push_declared_params_reader).to eq([:id])
         end
       end
 

spec/grape/validations/params_scope_spec.rb

@@ -121,6 +121,42 @@ def initialize(value)
     end
   end
 
+  context 'param alias' do
+    it do
+      subject.params do
+        requires :foo, as: :bar
+        optional :super, as: :hiper
+      end
+      subject.get('/alias') { "#{declared(params)['bar']}-#{declared(params)['hiper']}" }
+      get '/alias', foo: 'any', super: 'any2'
+
+      expect(last_response.status).to eq(200)
+      expect(last_response.body).to eq('any-any2')
+    end
+
+    it do
+      subject.params do
+        requires :foo, as: :bar, type: String, coerce_with: ->(c) { c.strip }
+      end
+      subject.get('/alias-coerced') { "#{params['bar']}-#{params['foo']}" }
+      get '/alias-coerced', foo: ' there we go '
+
+      expect(last_response.status).to eq(200)
+      expect(last_response.body).to eq('there we go-')
+    end
+
+    it do
+      subject.params do
+        requires :foo, as: :bar, allow_blank: false
+      end
+      subject.get('/alias-not-blank') {}
+      get '/alias-not-blank', foo: ''
+
+      expect(last_response.status).to eq(400)
+      expect(last_response.body).to eq('foo is empty')
+    end
+  end
+
   context 'array without coerce type explicitly given' do
     it 'sets the type based on first element' do
       subject.params do