Adding custom validation error messages

CHANGELOG.md

@@ -12,7 +12,7 @@
 * [#1255](https://github.com/ruby-grape/grape/pull/1255): Allow param type definition in `route_param` - [@namusyaka](https://github.com/namusyaka).
 * [#1257](https://github.com/ruby-grape/grape/pull/1257): Allow Proc, Symbol or String in `rescue_from with: ...` - [@namusyaka](https://github.com/namusyaka).
 * [#1285](https://github.com/ruby-grape/grape/pull/1285): Add a warning for errors appearing in `after` callbacks - [@gregormelhorn](https://github.com/gregormelhorn).
-* Your contribution here.
+* [#1295](https://github.com/ruby-grape/grape/pull/1295): Add custom validation messages for parameter exceptions - [@railsmith](https://github.com/railsmith).
 
 #### Fixes
 

README.md

@@ -41,6 +41,7 @@
   - [Custom Validators](#custom-validators)
   - [Validation Errors](#validation-errors)
   - [I18n](#i18n)
+  - [Custom Validation Messages](#custom-validation-messages)
 - [Headers](#headers)
 - [Routes](#routes)
 - [Helpers](#helpers)
@@ -1237,6 +1238,119 @@ end
 Grape supports I18n for parameter-related error messages, but will fallback to English if
 translations for the default locale have not been provided. See [en.yml](lib/grape/locale/en.yml) for message keys.
 
+### Custom Validation messages
+
+Grape supports custom validation messages for parameter-related and coerce-related error messages.
+
+#### `presence`, `allow_blank`, `values`, `regexp`
+
+```ruby
+params do
+  requires :name, values: { value: 1..10, message: 'not in range from 1 to 10' }, allow_blank: { value: false, message: 'cannot be blank' }, regexp: { value: /^[a-z]+$/, message: 'format is invalid' }, message: 'is required'
+end
+```
+#### `all_or_none_of`
+
+```ruby
+params do
+  optional :beer
+  optional :wine
+  optional :juice
+  all_or_none_of :beer, :wine, :juice, message: "all params are required or none is required"
+end
+```
+
+#### `mutually_exclusive`
+
+```ruby
+params do
+  optional :beer
+  optional :wine
+  optional :juice
+  mutually_exclusive :beer, :wine, :juice, message: "are mutually exclusive cannot pass both params"
+end
+```
+#### `exactly_one_of`
+
+```ruby
+params do
+  optional :beer
+  optional :wine
+  optional :juice
+  exactly_one_of :beer, :wine, :juice, message: {exactly_one: "are missing, exactly one parameter is required", mutual_exclusion: "are mutually exclusive, exactly one parameter is required"}
+end
+```
+#### `at_least_one_of`
+
+```ruby
+params do
+  optional :beer
+  optional :wine
+  optional :juice
+  at_least_one_of :beer, :wine, :juice, message: "are missing, please specify at least one param"
+end
+```
+#### `Coerce`
+
+```ruby
+params do
+  requires :int, type: {value: Integer, message: "type cast is invalid" }
+end
+```
+#### `With Lambdas`
+
+```ruby
+params do
+  requires :name, values: { value: -> { (1..10).to_a }, message: 'not in range from 1 to 10' }
+end
+```
+#### `Pass symbols for i18n translations`
+
+You can pass a symbol if you want i18n translations for your custom validation messages.
+
+```ruby
+params do
+  requires :name, message: :name_required
+end
+```
+```ruby
+# en.yml
+
+en:
+  grape:
+    errors:
+      format: ! '%{attributes} %{message}'
+      messages:
+        name_required: 'must be present'
+```
+
+#### `Overriding attribute names`
+
+You can also override attribute names.
+
+```ruby
+# en.yml
+
+en:
+  grape:
+    errors:
+      format: ! '%{attributes} %{message}'
+      messages:
+        name_required: 'must be present'
+      attributes:
+        name: 'Oops! Name'
+```
+Will produce 'Oops! Name must be present'
+
+#### `With Default`
+
+You cannot set a custom message option for Default as it requires interpolation `%{option1}: %{value1} is incompatible with %{option2}: %{value2}`. You can change the default error message for Default by changing the `incompatible_option_values` message key inside [en.yml](lib/grape/locale/en.yml)
+
+```ruby
+params do
+  requires :name, values: { value: -> { (1..10).to_a }, message: 'not in range from 1 to 10' }, default: 5
+end
+```
 ## Headers
 
 Request headers are available through the `headers` helper or from `env` in their original form.

lib/grape/dsl/parameters.rb

@@ -98,7 +98,7 @@ def requires(*attrs, &block)
         orig_attrs = attrs.clone
 
         opts = attrs.extract_options!.clone
-        opts[:presence] = true
+        opts[:presence] = { value: true, message: opts[:message] }
 
         if opts[:using]
           require_required_and_optional_fields(attrs.first, opts)
@@ -137,25 +137,25 @@ def optional(*attrs, &block)
       # Disallow the given parameters to be present in the same request.
       # @param attrs [*Symbol] parameters to validate
       def mutually_exclusive(*attrs)
-        validates(attrs, mutual_exclusion: true)
+        validates(attrs, mutual_exclusion: { value: true, message: extract_message_option(attrs) })
       end
 
       # Require exactly one of the given parameters to be present.
       # @param (see #mutually_exclusive)
       def exactly_one_of(*attrs)
-        validates(attrs, exactly_one_of: true)
+        validates(attrs, exactly_one_of: { value: true, message: extract_message_option(attrs) })
       end
 
       # Require at least one of the given parameters to be present.
       # @param (see #mutually_exclusive)
       def at_least_one_of(*attrs)
-        validates(attrs, at_least_one_of: true)
+        validates(attrs, at_least_one_of: { value: true, message: extract_message_option(attrs) })
       end
 
       # Require that either all given params are present, or none are.
       # @param (see #mutually_exclusive)
       def all_or_none_of(*attrs)
-        validates(attrs, all_or_none_of: true)
+        validates(attrs, all_or_none_of: { value: true, message: extract_message_option(attrs) })
       end
 
       # Define a block of validations which should be applied if and only if

lib/grape/exceptions/base.rb

@@ -38,15 +38,15 @@ def compose_message(key, attributes = {})
       end
 
       def problem(key, attributes)
-        translate_message("#{key}.problem", attributes)
+        translate_message("#{key}.problem".to_sym, attributes)
       end
 
       def summary(key, attributes)
-        translate_message("#{key}.summary", attributes)
+        translate_message("#{key}.summary".to_sym, attributes)
       end
 
       def resolution(key, attributes)
-        translate_message("#{key}.resolution", attributes)
+        translate_message("#{key}.resolution".to_sym, attributes)
       end
 
       def translate_attributes(keys, options = {})
@@ -60,7 +60,14 @@ def translate_attribute(key, options = {})
       end
 
       def translate_message(key, options = {})
-        translate("#{BASE_MESSAGES_KEY}.#{key}", options.reverse_merge(default: ''))
+        case key
+        when Symbol
+          translate("#{BASE_MESSAGES_KEY}.#{key}", options.reverse_merge(default: ''))
+        when Proc
+          key.call
+        else
+          key
+        end
       end
 
       def translate(key, options = {})

lib/grape/exceptions/incompatible_option_values.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class IncompatibleOptionValues < Base
       def initialize(option1, value1, option2, value2)
-        super(message: compose_message('incompatible_option_values', option1: option1, value1: value1, option2: option2, value2: value2))
+        super(message: compose_message(:incompatible_option_values, option1: option1, value1: value1, option2: option2, value2: value2))
       end
     end
   end

lib/grape/exceptions/invalid_accept_header.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class InvalidAcceptHeader < Base
       def initialize(message, headers)
-        super(message: compose_message('invalid_accept_header', message: message), status: 406, headers: headers)
+        super(message: compose_message(:invalid_accept_header, message: message), status: 406, headers: headers)
       end
     end
   end

lib/grape/exceptions/invalid_formatter.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class InvalidFormatter < Base
       def initialize(klass, to_format)
-        super(message: compose_message('invalid_formatter', klass: klass, to_format: to_format))
+        super(message: compose_message(:invalid_formatter, klass: klass, to_format: to_format))
       end
     end
   end

lib/grape/exceptions/invalid_message_body.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class InvalidMessageBody < Base
       def initialize(body_format)
-        super(message: compose_message('invalid_message_body', body_format: body_format), status: 400)
+        super(message: compose_message(:invalid_message_body, body_format: body_format), status: 400)
       end
     end
   end

lib/grape/exceptions/invalid_version_header.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class InvalidVersionHeader < Base
       def initialize(message, headers)
-        super(message: compose_message('invalid_version_header', message: message), status: 406, headers: headers)
+        super(message: compose_message(:invalid_version_header, message: message), status: 406, headers: headers)
       end
     end
   end

lib/grape/exceptions/invalid_versioner_option.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class InvalidVersionerOption < Base
       def initialize(strategy)
-        super(message: compose_message('invalid_versioner_option', strategy: strategy))
+        super(message: compose_message(:invalid_versioner_option, strategy: strategy))
       end
     end
   end

lib/grape/exceptions/invalid_with_option_for_represent.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class InvalidWithOptionForRepresent < Base
       def initialize
-        super(message: compose_message('invalid_with_option_for_represent'))
+        super(message: compose_message(:invalid_with_option_for_represent))
       end
     end
   end

lib/grape/exceptions/missing_group_type.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class MissingGroupTypeError < Base
       def initialize
-        super(message: compose_message('missing_group_type'))
+        super(message: compose_message(:missing_group_type))
       end
     end
   end

lib/grape/exceptions/missing_mime_type.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class MissingMimeType < Base
       def initialize(new_format)
-        super(message: compose_message('missing_mime_type', new_format: new_format))
+        super(message: compose_message(:missing_mime_type, new_format: new_format))
       end
     end
   end

lib/grape/exceptions/missing_option.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class MissingOption < Base
       def initialize(option)
-        super(message: compose_message('missing_option', option: option))
+        super(message: compose_message(:missing_option, option: option))
       end
     end
   end

lib/grape/exceptions/missing_vendor_option.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class MissingVendorOption < Base
       def initialize
-        super(message: compose_message('missing_vendor_option'))
+        super(message: compose_message(:missing_vendor_option))
       end
     end
   end

lib/grape/exceptions/unknown_options.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class UnknownOptions < Base
       def initialize(options)
-        super(message: compose_message('unknown_options', options: options))
+        super(message: compose_message(:unknown_options, options: options))
       end
     end
   end

lib/grape/exceptions/unknown_parameter.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class UnknownParameter < Base
       def initialize(param)
-        super(message: compose_message('unknown_parameter', param: param))
+        super(message: compose_message(:unknown_parameter, param: param))
       end
     end
   end

lib/grape/exceptions/unknown_validator.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class UnknownValidator < Base
       def initialize(validator_type)
-        super(message: compose_message('unknown_validator', validator_type: validator_type))
+        super(message: compose_message(:unknown_validator, validator_type: validator_type))
       end
     end
   end

lib/grape/exceptions/unsupported_group_type.rb

@@ -3,7 +3,7 @@ module Grape
   module Exceptions
     class UnsupportedGroupTypeError < Base
       def initialize
-        super(message: compose_message('unsupported_group_type'))
+        super(message: compose_message(:unsupported_group_type))
       end
     end
   end

lib/grape/exceptions/validation.rb

@@ -9,8 +9,7 @@ class Validation < Grape::Exceptions::Base
       def initialize(args = {})
         fail 'Params are missing:' unless args.key? :params
         @params = args[:params]
-        @message_key = args[:message_key]
-        args[:message] = translate_message(args[:message_key]) if args.key? :message_key
+        args[:message] = translate_message(args[:message]) if args.key? :message
         super
       end