Add full support for iso8601 parsing

Signed-off-by: Lorenzo <[email protected]>

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/gorilla/websocket v1.4.1
 	github.com/kr/pretty v0.1.0 // indirect
 	github.com/leodido/go-urn v1.1.0 // indirect
+	github.com/relvacode/iso8601 v1.3.0 // indirect
 	github.com/sirupsen/logrus v1.4.2
 	github.com/stretchr/testify v1.8.0
 	golang.org/x/sys v0.0.0-20220804214406-8e32c043e418 // indirect

go.sum

@@ -22,6 +22,8 @@ github.com/leodido/go-urn v1.1.0 h1:Sm1gr51B1kKyfD2BlRcLSiEkffoG96g6TPv6eRoEiB8=
 github.com/leodido/go-urn v1.1.0/go.mod h1:+cyI34gQWZcE1eQU7NVgKkkzdXDQHr1dBMtdAPozLkw=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/relvacode/iso8601 v1.3.0 h1:HguUjsGpIMh/zsTczGN3DVJFxTU/GX+MMmzcKoMO7ko=
+github.com/relvacode/iso8601 v1.3.0/go.mod h1:FlNp+jz+TXpyRqgmM7tnzHHzBnz776kmAH2h3sZCn0I=
 github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

ocpp1.6/types/datetime.go

@@ -2,14 +2,13 @@ package types
 
 import (
 	"encoding/json"
-	"strings"
+	"errors"
 	"time"
-)
 
-// ISO8601 time format, assuming Zulu timestamp.
-const ISO8601 = "2006-01-02T15:04:05Z"
+	"github.com/relvacode/iso8601"
+)
 
-// DateTimeFormat to be used for all OCPP messages.
+// DateTimeFormat to be used when serializing all OCPP messages.
 //
 // The default dateTime format is RFC3339.
 // Change this if another format is desired.
@@ -25,24 +24,31 @@ func NewDateTime(time time.Time) *DateTime {
 	return &DateTime{Time: time}
 }
 
+func null(b []byte) bool {
+	if len(b) != 4 {
+		return false
+	}
+	if b[0] != 'n' && b[1] != 'u' && b[2] != 'l' && b[3] != 'l' {
+		return false
+	}
+	return true
+}
+
 func (dt *DateTime) UnmarshalJSON(input []byte) error {
-	strInput := string(input)
-	strInput = strings.Trim(strInput, `"`)
-	if DateTimeFormat == "" {
-		var defaultTime time.Time
-		err := json.Unmarshal(input, &defaultTime)
-		if err != nil {
-			return err
-		}
-		dt.Time = defaultTime.Local()
+	// Do not parse null timestamps
+	if null(input) {
+		return nil
+	}
+	// Assert that timestamp is a string
+	if len(input) > 0 && input[0] == '"' && input[len(input)-1] == '"' {
+		input = input[1 : len(input)-1]
 	} else {
-		newTime, err := time.Parse(DateTimeFormat, strInput)
-		if err != nil {
-			return err
-		}
-		dt.Time = newTime.Local()
+		return errors.New("timestamp not enclosed in double quotes")
 	}
-	return nil
+	// Parse ISO8601
+	var err error
+	dt.Time, err = iso8601.Parse(input)
+	return err
 }
 
 func (dt *DateTime) MarshalJSON() ([]byte, error) {

ocpp2.0.1/types/datetime.go

@@ -2,11 +2,13 @@ package types
 
 import (
 	"encoding/json"
-	"strings"
+	"errors"
 	"time"
+
+	"github.com/relvacode/iso8601"
 )
 
-// DateTimeFormat to be used for all OCPP messages.
+// DateTimeFormat to be used when serializing all OCPP messages.
 //
 // The default dateTime format is RFC3339.
 // Change this if another format is desired.
@@ -22,36 +24,38 @@ func NewDateTime(time time.Time) *DateTime {
 	return &DateTime{Time: time}
 }
 
-// Creates a new DateTime struct, embedding a struct generated using time.Now().
-func Now() *DateTime {
-	return &DateTime{Time: time.Now()}
+func null(b []byte) bool {
+	if len(b) != 4 {
+		return false
+	}
+	if b[0] != 'n' && b[1] != 'u' && b[2] != 'l' && b[3] != 'l' {
+		return false
+	}
+	return true
 }
 
 func (dt *DateTime) UnmarshalJSON(input []byte) error {
-	strInput := string(input)
-	strInput = strings.Trim(strInput, `"`)
-	if DateTimeFormat == "" {
-		var defaultTime time.Time
-		err := json.Unmarshal(input, &defaultTime)
-		if err != nil {
-			return err
-		}
-		dt.Time = defaultTime.Local()
+	// Do not parse null timestamps
+	if null(input) {
+		return nil
+	}
+	// Assert that timestamp is a string
+	if len(input) > 0 && input[0] == '"' && input[len(input)-1] == '"' {
+		input = input[1 : len(input)-1]
 	} else {
-		newTime, err := time.Parse(DateTimeFormat, strInput)
-		if err != nil {
-			return err
-		}
-		dt.Time = newTime.Local()
+		return errors.New("timestamp not enclosed in double quotes")
 	}
-	return nil
+	// Parse ISO8601
+	var err error
+	dt.Time, err = iso8601.Parse(input)
+	return err
 }
 
 func (dt *DateTime) MarshalJSON() ([]byte, error) {
 	if DateTimeFormat == "" {
 		return json.Marshal(dt.Time)
 	}
-	timeStr := FormatTimestamp(dt.Time)
+	timeStr := dt.FormatTimestamp()
 	return json.Marshal(timeStr)
 }