Add ability to validate map data (#752)

* Implement ValidateMapCtx func for validating map data

* Add ValidateMap func for validating map data with an empty context

* Implement a basic example of ValidateMap method

* Update ValidateMapCtx method, so it can validate nested maps

* Due to changes in ValidateMapCtx, make some updates on ValidateMap method

* Update tests due to changes in ValidateMap method

* Create a basic test for validating nested maps

* Handle error when invalid data is supplied for diving

_examples/map-validation/main.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"fmt"
+	"github.com/go-playground/validator/v10"
+)
+
+var validate *validator.Validate
+
+func main() {
+	validate = validator.New()
+
+	validateMap()
+	validateNestedMap()
+}
+
+func validateMap() {
+	user := map[string]interface{}{"name": "Arshiya Kiani", "email": "zytel3301@gmail.com"}
+
+	// Every rule will be applied to the item of the data that the offset of rule is pointing to.
+	// So if you have a field "email": "omitempty,required,email", the validator will apply these
+	// rules to offset of email in user data
+	rules := map[string]interface{}{"name": "required,min=8,max=32", "email": "omitempty,required,email"}
+
+	// ValidateMap will return map[string]error.
+	// The offset of every item in errs is the name of invalid field and the value
+	// is the message of error. If there was no error, ValidateMap method will
+	// return an EMPTY map of errors, not nil. If you want to check that
+	// if there was an error or not, you must check the length of the return value
+	errs := validate.ValidateMap(user, rules)
+
+	if len(errs) > 0 {
+		fmt.Println(errs)
+		// The user is invalid
+	}
+
+	// The user is valid
+}
+
+func validateNestedMap() {
+
+	data := map[string]interface{}{
+		"name":  "Arshiya Kiani",
+		"email": "zytel3301@gmail.com",
+		"details": map[string]interface{}{
+			"family_members": map[string]interface{}{
+				"father_name": "Micheal",
+				"mother_name": "Hannah",
+			},
+			"salary": "1000",
+		},
+	}
+
+	// Rules must be set as the structure as the data itself. If you want to dive into the
+	// map, just declare its rules as a map
+	rules := map[string]interface{}{
+		"name":  "min=4,max=32",
+		"email": "required,email",
+		"details": map[string]interface{}{
+			"family_members": map[string]interface{}{
+				"father_name": "required,min=4,max=32",
+				"mother_name": "required,min=4,max=32",
+			},
+			"salary": "number",
+		},
+	}
+
+	if len(validate.ValidateMap(data, rules)) == 0 {
+		// Data is valid
+	}
+
+	// Data is invalid
+}

validator_instance.go

@@ -143,6 +143,33 @@ func (v *Validate) SetTagName(name string) {
 	v.tagName = name
 }
 
+// ValidateMapCtx validates a map using a map of validation rules and allows passing of contextual
+// validation validation information via context.Context.
+func (v Validate) ValidateMapCtx(ctx context.Context, data map[string]interface{}, rules map[string]interface{}) map[string]interface{} {
+	errs := make(map[string]interface{})
+	for field, rule := range rules {
+		if reflect.ValueOf(rule).Kind() == reflect.Map && reflect.ValueOf(data[field]).Kind() == reflect.Map {
+			err := v.ValidateMapCtx(ctx, data[field].(map[string]interface{}), rule.(map[string]interface{}))
+			if len(err) > 0 {
+				errs[field] = err
+			}
+		} else if reflect.ValueOf(rule).Kind() == reflect.Map {
+			errs[field] = errors.New("The field: '" + field + "' is not a map to dive")
+		} else {
+			err := v.VarCtx(ctx, data[field], rule.(string))
+			if err != nil {
+				errs[field] = err
+			}
+		}
+	}
+	return errs
+}
+
+// ValidateMap validates map data form a map of tags
+func (v *Validate) ValidateMap(data map[string]interface{}, rules map[string]interface{}) map[string]interface{} {
+	return v.ValidateMapCtx(context.Background(), data, rules)
+}
+
 // RegisterTagNameFunc registers a function to get alternate names for StructFields.
 //
 // eg. to use the names which have been specified for JSON representations of structs, rather than normal Go field names: