Merge pull request ruby-grape#239 from adamgotterer/validation

Validation updates: call `before` before validation / added param value when raising ValidationError

Author: dblock

.gitignore

@@ -16,6 +16,7 @@ tmtags
 
 ## VIM
 *.swp
+*.swo
 
 ## RUBYMINE
 .idea

README.markdown

@@ -214,7 +214,7 @@ end
 
 ## Parameter Validation and Coercion
 
-You can define validations and coercion options for your parameters using `params`.
+You can define validations and coercion options for your parameters using a `params` block.
 
 ```ruby
 params do
@@ -260,22 +260,22 @@ end
 
 ### Custom Validators
 ```ruby
-class doit < Grape::Validations::Validator
+class AlphaNumeric < Grape::Validations::Validator
   def validate_param!(attr_name, params)
-    unless params[attr_name] == 'im custom'
-      throw :error, :status => 400, :message => "#{attr_name}: is not custom!"
+    unless params[attr_name] =~ /^[[:alnum:]]+$/
+      throw :error, :status => 400, :message => "#{attr_name}: must consist of alpha-numeric characters"
     end    
   end
 end  
 ```
 
 ```ruby
 params do
-  requires :name, :doit => true
+  requires :username, :alpha_numeric => true
 end
 ```
 
-You can also create custom classes that take additional parameters
+You can also create custom classes that take parameters
 ```ruby
 class Length < Grape::Validations::SingleOptionValidator
   def validate_param!(attr_name, params)
@@ -292,6 +292,20 @@ params do
 end
 ```
 
+### Validation Errors
+When validation and coercion erros occur an exception of type `ValidationError` is raised.
+If the exception goes uncaught it will respond with a status of 400 and an error message.
+You can rescue a `ValidationError` and respond with a custom response.
+```ruby
+rescue_from ValidationError do |e|
+    Rack::Response.new({
+        'status' => e.status,
+        'message' => e.message,
+        'param' => e.param
+    }.to_json, e.status)    
+end 
+```
+
 
 
 ## Headers

lib/grape/endpoint.rb

@@ -293,11 +293,12 @@ def run(env)
       self.extend helpers
       cookies.read(@request)
 
+      run_filters befores
+
       Array(settings[:validations]).each do |validator|
         validator.validate!(params)
       end
 
-      run_filters befores
       response_text = instance_eval &self.block
       run_filters afters
       cookies.write(header)

lib/grape/exceptions/validation_error.rb

@@ -1,4 +1,10 @@
 require 'grape/exceptions/base'
 
 class ValidationError < Grape::Exceptions::Base
+  attr_accessor :param
+
+  def initialize(args = {})
+    @param = args[:param].to_s if args.has_key? :param
+    super
+  end
 end

lib/grape/validations/coerce.rb

@@ -12,7 +12,7 @@ def validate_param!(attr_name, params)
         if valid_type?(new_value)
           params[attr_name] = new_value
         else
-          raise ValidationError, :status => 400, :message => "invalid parameter: #{attr_name}"
+          raise ValidationError, :status => 400, :param => attr_name, :message => "invalid parameter: #{attr_name}"
         end
       end
 

lib/grape/validations/presence.rb

@@ -3,7 +3,7 @@ module Validations
     class PresenceValidator < Validator
       def validate_param!(attr_name, params)
         unless params.has_key?(attr_name)
-          raise ValidationError, :status => 400, :message => "missing parameter: #{attr_name}"
+          raise ValidationError, :status => 400, :param => attr_name, :message => "missing parameter: #{attr_name}"
         end
       end
     end

lib/grape/validations/regexp.rb

@@ -4,7 +4,7 @@ module Validations
     class RegexpValidator < SingleOptionValidator
       def validate_param!(attr_name, params)
         if params[attr_name] && !( params[attr_name].to_s =~ @option )
-          raise ValidationError, :status => 400, :message => "invalid parameter: #{attr_name}"
+          raise ValidationError, :status => 400, :param => attr_name, :message => "invalid parameter: #{attr_name}"
         end
       end
     end