Make Each and When context aware (#130)

* Minor linting tweaks

* Make Each and When context aware

Author: NathanBaulch

README.md

@@ -82,16 +82,6 @@ to achieve this purpose. A single struct can have rules for multiple fields, and
 rules. For example,
 
 ```go
-package main
-
-import (
-	"fmt"
-	"regexp"
-
-	"github.com/go-ozzo/ozzo-validation/v4"
-	"github.com/go-ozzo/ozzo-validation/v4/is"
-)
-
 type Address struct {
 	Street string
 	City   string
@@ -112,19 +102,17 @@ func (a Address) Validate() error {
 	)
 }
 
-func main() {
-	a := Address{
-		Street: "123",
-		City:   "Unknown",
-		State:  "Virginia",
-		Zip:    "12345",
-	}
-
-	err := a.Validate()
-	fmt.Println(err)
-	// Output:
-	// Street: the length must be between 5 and 50; State: must be in a valid format.
+a := Address{
+    Street: "123",
+    City:   "Unknown",
+    State:  "Virginia",
+    Zip:    "12345",
 }
+
+err := a.Validate()
+fmt.Println(err)
+// Output:
+// Street: the length must be between 5 and 50; State: must be in a valid format.
 ```
 
 Note that when calling `validation.ValidateStruct` to validate a struct, you should pass to the method a pointer 
@@ -457,8 +445,6 @@ You can also customize the pre-defined error(s) of a built-in rule such that the
 instance of the rule. For example, the `Required` rule uses the pre-defined error `ErrRequired`. You can customize it
 during the application initialization:
 ```go
-import "github.com/go-ozzo/ozzo-validation/v4"
-
 validation.ErrRequired = validation.ErrRequired.SetMessage("the value is required") 
 ```
 

date_test.go

@@ -84,8 +84,8 @@ func TestDateRule_MinMax(t *testing.T) {
 	if assert.NotNil(t, err) {
 		assert.Equal(t, "the date is out of range", err.Error())
 	}
-	err2 := r2.Validate("2021-01-02")
+	err = r2.Validate("2021-01-02")
 	if assert.NotNil(t, err) {
-		assert.Equal(t, "the date is out of range", err2.Error())
+		assert.Equal(t, "the date is out of range", err.Error())
 	}
 }

each.go

@@ -5,6 +5,7 @@
 package validation
 
 import (
+	"context"
 	"errors"
 	"reflect"
 	"strconv"
@@ -26,21 +27,38 @@ type EachRule struct {
 
 // Validate loops through the given iterable and calls the Ozzo Validate() method for each value.
 func (r EachRule) Validate(value interface{}) error {
+	return r.ValidateWithContext(nil, value)
+}
+
+// ValidateWithContext loops through the given iterable and calls the Ozzo ValidateWithContext() method for each value.
+func (r EachRule) ValidateWithContext(ctx context.Context, value interface{}) error {
 	errs := Errors{}
 
 	v := reflect.ValueOf(value)
 	switch v.Kind() {
 	case reflect.Map:
 		for _, k := range v.MapKeys() {
 			val := r.getInterface(v.MapIndex(k))
-			if err := Validate(val, r.rules...); err != nil {
+			var err error
+			if ctx == nil {
+				err = Validate(val, r.rules...)
+			} else {
+				err = ValidateWithContext(ctx, val, r.rules...)
+			}
+			if err != nil {
 				errs[r.getString(k)] = err
 			}
 		}
 	case reflect.Slice, reflect.Array:
 		for i := 0; i < v.Len(); i++ {
 			val := r.getInterface(v.Index(i))
-			if err := Validate(val, r.rules...); err != nil {
+			var err error
+			if ctx == nil {
+				err = Validate(val, r.rules...)
+			} else {
+				err = ValidateWithContext(ctx, val, r.rules...)
+			}
+			if err != nil {
 				errs[strconv.Itoa(i)] = err
 			}
 		}

each_test.go

@@ -1,6 +1,9 @@
 package validation
 
 import (
+	"context"
+	"errors"
+	"strings"
 	"testing"
 )
 
@@ -37,3 +40,35 @@ func TestEach(t *testing.T) {
 		assertError(t, test.err, err, test.tag)
 	}
 }
+
+func TestEachWithContext(t *testing.T) {
+	rule := Each(WithContext(func(ctx context.Context, value interface{}) error {
+		if !strings.Contains(value.(string), ctx.Value("contains").(string)) {
+			return errors.New("unexpected value")
+		}
+		return nil
+	}))
+	ctx1 := context.WithValue(context.Background(), "contains", "abc")
+	ctx2 := context.WithValue(context.Background(), "contains", "xyz")
+
+	tests := []struct {
+		tag   string
+		value interface{}
+		ctx   context.Context
+		err   string
+	}{
+		{"t1.1", map[string]string{"key": "abc"}, ctx1, ""},
+		{"t1.2", map[string]string{"key": "abc"}, ctx2, "key: unexpected value."},
+		{"t1.3", map[string]string{"key": "xyz"}, ctx1, "key: unexpected value."},
+		{"t1.4", map[string]string{"key": "xyz"}, ctx2, ""},
+		{"t1.5", []string{"abc"}, ctx1, ""},
+		{"t1.6", []string{"abc"}, ctx2, "0: unexpected value."},
+		{"t1.7", []string{"xyz"}, ctx1, "0: unexpected value."},
+		{"t1.8", []string{"xyz"}, ctx2, ""},
+	}
+
+	for _, test := range tests {
+		err := ValidateWithContext(test.ctx, test.value, rule)
+		assertError(t, test.err, err, test.tag)
+	}
+}

error.go

@@ -33,7 +33,7 @@ type (
 	}
 
 	// Errors represents the validation errors that are indexed by struct field names, map or slice keys.
-	// values are Error or Errors (for map,slice and array error value is Errors).
+	// values are Error or Errors (for map, slice and array error value is Errors).
 	Errors map[string]error
 
 	// InternalError represents an error that should NOT be treated as a validation error.
@@ -118,9 +118,11 @@ func (es Errors) Error() string {
 		return ""
 	}
 
-	keys := []string{}
+	keys := make([]string, len(es))
+	i := 0
 	for key := range es {
-		keys = append(keys, key)
+		keys[i] = key
+		i++
 	}
 	sort.Strings(keys)
 
@@ -130,9 +132,9 @@ func (es Errors) Error() string {
 			s.WriteString("; ")
 		}
 		if errs, ok := es[key].(Errors); ok {
-			fmt.Fprintf(&s, "%v: (%v)", key, errs)
+			_, _ = fmt.Fprintf(&s, "%v: (%v)", key, errs)
 		} else {
-			fmt.Fprintf(&s, "%v: %v", key, es[key].Error())
+			_, _ = fmt.Fprintf(&s, "%v: %v", key, es[key].Error())
 		}
 	}
 	s.WriteString(".")

is/rules.go

@@ -6,11 +6,11 @@
 package is
 
 import (
-	validation "github.com/go-ozzo/ozzo-validation/v4"
 	"regexp"
 	"unicode"
 
 	"github.com/asaskevich/govalidator"
+	validation "github.com/go-ozzo/ozzo-validation/v4"
 )
 
 var (

multipleof_test.go

@@ -10,10 +10,10 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestMultipleof(t *testing.T) {
-	r := MultipleOf(int(10))
-	assert.Equal(t, "must be multiple of 10", r.Validate(int(11)).Error())
-	assert.Equal(t, nil, r.Validate(int(20)))
+func TestMultipleOf(t *testing.T) {
+	r := MultipleOf(10)
+	assert.Equal(t, "must be multiple of 10", r.Validate(11).Error())
+	assert.Equal(t, nil, r.Validate(20))
 	assert.Equal(t, "cannot convert float32 to int64", r.Validate(float32(20)).Error())
 
 	r2 := MultipleOf("some string ....")
@@ -26,7 +26,7 @@ func TestMultipleof(t *testing.T) {
 
 }
 
-func Test_Multipleof_Error(t *testing.T) {
+func Test_MultipleOf_Error(t *testing.T) {
 	r := MultipleOf(10)
 	assert.Equal(t, "must be multiple of 10", r.Validate(3).Error())
 

string_test.go

@@ -6,9 +6,8 @@ package validation
 
 import (
 	"database/sql"
-	"testing"
-
 	"reflect"
+	"testing"
 
 	"github.com/stretchr/testify/assert"
 )

struct.go

@@ -52,26 +52,22 @@ func (e ErrFieldNotFound) Error() string {
 //        Value string
 //    }{"name", "demo"}
 //    err := validation.ValidateStruct(&value,
-//         validation.Field(&a.Name, validation.Required),
-//         validation.Field(&a.Value, validation.Required, validation.Length(5, 10)),
+//        validation.Field(&a.Name, validation.Required),
+//        validation.Field(&a.Value, validation.Required, validation.Length(5, 10)),
 //    )
 //    fmt.Println(err)
 //    // Value: the length must be between 5 and 10.
 //
 // An error will be returned if validation fails.
 func ValidateStruct(structPtr interface{}, fields ...*FieldRules) error {
-	return validateStruct(nil, structPtr, fields...)
+	return ValidateStructWithContext(nil, structPtr, fields...)
 }
 
 // ValidateStructWithContext validates a struct with the given context.
 // The only difference between ValidateStructWithContext and ValidateStruct is that the former will
 // validate struct fields with the provided context.
 // Please refer to ValidateStruct for the detailed instructions on how to use this function.
 func ValidateStructWithContext(ctx context.Context, structPtr interface{}, fields ...*FieldRules) error {
-	return validateStruct(ctx, structPtr, fields...)
-}
-
-func validateStruct(ctx context.Context, structPtr interface{}, fields ...*FieldRules) error {
 	value := reflect.ValueOf(structPtr)
 	if value.Kind() != reflect.Ptr || !value.IsNil() && value.Elem().Kind() != reflect.Struct {
 		// must be a pointer to a struct

struct_test.go

@@ -86,7 +86,7 @@ func TestValidateStruct(t *testing.T) {
 		{"t2.4", &m1, []*FieldRules{Field(&m1.D, Length(0, 5))}, ""},
 		{"t2.5", &m1, []*FieldRules{Field(&m1.F, Length(0, 5))}, ""},
 		{"t2.6", &m1, []*FieldRules{Field(&m1.H, Each(&validateAbc{})), Field(&m1.I, Each(&validateAbc{}))}, ""},
-		{"t2.6", &m1, []*FieldRules{Field(&m1.H, Each(&validateXyz{})), Field(&m1.I, Each(&validateXyz{}))}, "H: (0: error xyz; 1: error xyz.); I: (foo: error xyz.)."},
+		{"t2.7", &m1, []*FieldRules{Field(&m1.H, Each(&validateXyz{})), Field(&m1.I, Each(&validateXyz{}))}, "H: (0: error xyz; 1: error xyz.); I: (foo: error xyz.)."},
 		// non-struct pointer
 		{"t3.1", m1, []*FieldRules{}, ErrStructPointer.Error()},
 		{"t3.2", nil, []*FieldRules{}, ErrStructPointer.Error()},
@@ -189,6 +189,7 @@ func TestValidateStructWithContext(t *testing.T) {
 		assert.Equal(t, "Value: the length must be between 5 and 10.", err.Error())
 	}
 }
+
 func Test_getErrorFieldName(t *testing.T) {
 	var s1 Struct1
 	v1 := reflect.ValueOf(&s1).Elem()