Add full form access to rule functions

README.md

@@ -179,7 +179,7 @@ Send request to the server using curl or postman: `curl GET "http://localhost:90
 ```go
 func init() {
  // simple example
- govalidator.AddCustomRule("must_john", func(field string, rule string, message string, value interface{}) error {
+ govalidator.AddCustomRule("must_john", func(field string, rule string, message string, value interface{}, form map[string]interface{}) error {
  val := value.(string)
  if val != "john" || val != "John" {
  return fmt.Errorf("The %s field must be John or john", field)
@@ -189,7 +189,7 @@ func init() {
 
  // custom rules to take fixed length word.
  // e.g: word:5 will throw error if the field does not contain exact 5 word
- govalidator.AddCustomRule("word", func(field string, rule string, message string, value interface{}) error {
+ govalidator.AddCustomRule("word", func(field string, rule string, message string, value interface{}, form map[string]interface{}) error {
  valSlice := strings.Fields(value.(string))
  l, _ := strconv.Atoi(strings.TrimPrefix(rule, "word:")) //handle other error
  if len(valSlice) != l {
@@ -202,6 +202,60 @@ func init() {
 ```
 Note: Array, map, slice can be validated by adding custom rules.
 
+You can use the `form` parameter to compare one field with another.
+```go
+govalidator.AddCustomRule("greater_than", (f string, rule string, message string, v interface{}, form map[string]interface{}) error {
+ if form == nil { // All comparison rules should check if the form is provided
+ panic(errors.New("No form provided for comparison rule"))
+ }
+
+ compareToKey := strings.TrimPrefix(rule, "greater_than:")
+ err := fmt.Errorf("The %s field must be greater than the %s field", f, compareToKey)
+ compareToField := form[compareToKey]
+
+ if compareToField == nil { // Field to compare to doesn't exist or is empty
+ return err
+ }
+
+ // Get the value of the field we want to compare to
+ var compareToValue int
+ rv := reflect.ValueOf(compareToField)
+ switch rv.Kind() {
+ case reflect.String:
+ v, atoiErr := strconv.Atoi(compareToField.(string))
+ if atoiErr != nil {
+ panic(errStringToInt)
+ }
+ compareToValue = v
+ case reflect.Int:
+ compareToValue = compareToField.(int)
+ //...
+ // Handle other types such as float
+ }
+
+ // Do the comparison
+ rv2 := reflect.ValueOf(v)
+ switch rv2.Kind() {
+ case reflect.Int:
+ if v.(int) <= compareToValue {
+ return err
+ }
+ case reflect.String:
+ vInt, atoiErr := strconv.Atoi(v.(string))
+ if atoiErr != nil {
+ panic(errStringToInt)
+ }
+ if vInt <= compareToValue {
+ return err
+ }
+ //...
+ // Handle other types
+ }
+
+ return nil
+})
+```
+
 ### Custom Message/ Localization
 If you need to translate validation message you can pass messages as options.
 

doc/CUSTOM_RULE.md

@@ -20,7 +20,7 @@ import (
 func init() {
  // custom rules to take fixed length word.
  // e.g: max_word:5 will throw error if the field contains more than 5 words
- govalidator.AddCustomRule("max_word", func(field string, rule string, message string, value interface{}) error {
+ govalidator.AddCustomRule("max_word", func(field string, rule string, message string, value interface{}, form map[string]interface{}) error {
  valSlice := strings.Fields(value.(string))
  l, _ := strconv.Atoi(strings.TrimPrefix(rule, "max_word:")) //handle other error
  if len(valSlice) > l {