Merge pull request #8 from tfrench-uber/json

Unmarshal: support non-nested json tags

etc.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 )
 
-func validTag(filed reflect.StructField) bool {
+func validTag(filed reflect.StructField, tag string) bool {
 	return !(filed.Tag.Get(tag) == "" ||
 		filed.Tag.Get(tag) == "-")
 }

unmarshal.go

@@ -3,18 +3,22 @@ package njson
 import (
 	"encoding/json"
 	"errors"
+	"fmt"
 	"reflect"
+	"strings"
 
 	"github.com/tidwall/gjson"
 )
 
-const tag string = "njson"
+const (
+	njsonTag = "njson"
+	jsonTag  = "json"
+)
 
 var jsonNumberType = reflect.TypeOf(json.Number(""))
 
 // Unmarshal used to unmarshal nested json using "njson" tag
 func Unmarshal(data []byte, v interface{}) (err error) {
-
 	// catch code panic and return error message
 	defer func() {
 		if r := recover(); r != nil {
@@ -24,7 +28,7 @@ func Unmarshal(data []byte, v interface{}) (err error) {
 			case error:
 				err = x
 			default:
-				err = errors.New("Unknown panic")
+				err = fmt.Errorf("unknown panic: %v", r)
 			}
 		}
 	}()
@@ -34,12 +38,25 @@ func Unmarshal(data []byte, v interface{}) (err error) {
 	for i := 0; i < elem.NumField(); i++ {
 		field := elem.Field(i)
 
-		if !(validTag(typeOfT.Field(i)) && field.CanSet()) {
+		// Check that the tag is either "json" or "njson", and can be set
+		if (!validTag(typeOfT.Field(i), njsonTag) && !validTag(typeOfT.Field(i), jsonTag)) || !field.CanSet() {
 			continue
 		}
 
+		// Assume "njson" by default, but change to "json" if tag matches
+		fieldName := typeOfT.Field(i).Tag.Get(njsonTag)
+		if validTag(typeOfT.Field(i), jsonTag) {
+			fieldName = typeOfT.Field(i).Tag.Get(jsonTag)
+
+			// Only support true "json" tags:
+			// if a tag is nested, it must use the "njson" tag
+			if len(strings.Split(fieldName, ".")) > 1 {
+				return fmt.Errorf("invalid json tag: %s", fieldName)
+			}
+		}
+
 		// get field value by tag
-		result := gjson.GetBytes(data, typeOfT.Field(i).Tag.Get(tag))
+		result := gjson.GetBytes(data, fieldName)
 
 		// if field type json.Number
 		if v != nil && field.Kind() == reflect.String && field.Type() == jsonNumberType {
@@ -60,7 +77,7 @@ func Unmarshal(data []byte, v interface{}) (err error) {
 		}
 	}
 
-	return nil
+	return
 }
 
 func unmarshalSlice(results []gjson.Result, field reflect.Type) interface{} {

unmarshal_test.go

@@ -260,7 +260,7 @@ func TestUnmarshalSlices(t *testing.T) {
 			[
 				[
 					601, 602, 603
-				],
+				]
 			]
 
 		],
@@ -429,7 +429,7 @@ func TestUnmarshalComplex(t *testing.T) {
 		],
 		"time_1": "2021-01-11T23:56:51.141Z",
 		"time_2": "2021-01-11T23:56:51.141+01:00",
-		"time_3": "2021-01-11T23:56:51.141-01:00",
+		"time_3": "2021-01-11T23:56:51.141-01:00"
 	  }
 	`
 
@@ -550,3 +550,93 @@ func TestUnmarshalMoreComplex(t *testing.T) {
 	}
 
 }
+
+func TestUnmarshalJson(t *testing.T) {
+	t.Run("success", func(t *testing.T) {
+		json := `
+		{
+			"name": {"first": "Mohamed", "last": "Shapan"},
+			"age": 26,
+			"friends": [
+				{"first": "Asma", "age": 26},
+				{"first": "Ahmed", "age": 25},
+				{"first": "Mahmoud", "age": 30}
+			]
+		}`
+
+		type Name struct {
+			First string `njson:"first"`
+			Last  string `njson:"last"`
+		}
+
+		type User struct {
+			Name    Name   `njson:"name"`
+			Age     int    `json:"age"`
+			Friends []Name `json:"friends"`
+		}
+
+		actual := User{}
+
+		err := Unmarshal([]byte(json), &actual)
+		if err != nil {
+			t.Error(err)
+		}
+
+		var friends []Name
+		friends = append(friends, Name{
+			First: "Asma",
+		})
+
+		friends = append(friends, Name{
+			First: "Ahmed",
+		})
+
+		friends = append(friends, Name{
+			First: "Mahmoud",
+		})
+
+		expected := User{
+			Name: Name{
+				First: "Mohamed",
+				Last:  "Shapan",
+			},
+			Age:     26,
+			Friends: friends,
+		}
+
+		diff := cmp.Diff(expected, actual)
+		if diff != "" {
+			t.Error(diff)
+		}
+	})
+
+	t.Run("fail", func(t *testing.T) {
+		json := `
+		{
+			"name": {"first": "Mohamed", "last": "Shapan"},
+			"age": 26,
+			"friends": [
+				{"first": "Asma", "age": 26},
+				{"first": "Ahmed", "age": 25},
+				{"first": "Mahmoud", "age": 30}
+			]
+		}`
+
+		type Name struct {
+			First string `njson:"first"`
+			Last  string `njson:"last"`
+		}
+
+		type User struct {
+			Name    string `json:"name.first"`
+			Age     int    `json:"age"`
+			Friends []Name `json:"friends"`
+		}
+
+		actual := User{}
+
+		if err := Unmarshal([]byte(json), &actual); err == nil {
+			t.Error("error should not be nil")
+		}
+	})
+}