new /x/jsonx and /x/mathx util sub-packages

x/jsonx/iso8601.go

@@ -0,0 +1,112 @@
+package jsonx
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	// ISO8601Layout holds the time layout for the the javascript iso time.
+	// Read more at: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString.
+	ISO8601Layout = "2006-01-02T15:04:05"
+	// ISO8601ZLayout same as ISO8601Layout but with the timezone suffix.
+	ISO8601ZLayout = "2006-01-02T15:04:05Z"
+)
+
+// ISO8601 describes a time compatible with javascript time format.
+type ISO8601 time.Time
+
+// ParseISO8601 reads from "s" and returns the ISO8601 time.
+func ParseISO8601(s string) (ISO8601, error) {
+	if s == "" || s == "null" {
+		return ISO8601{}, nil
+	}
+
+	var (
+		tt  time.Time
+		err error
+	)
+
+	if s[len(s)-1] == 'Z' {
+		tt, err = time.Parse(ISO8601ZLayout, s)
+	} else {
+		tt, err = time.Parse(ISO8601Layout, s)
+	}
+
+	if err != nil {
+		return ISO8601{}, err
+	}
+
+	return ISO8601(tt.UTC()), nil
+}
+
+// UnmarshalJSON parses the "b" into ISO8601 time.
+func (t *ISO8601) UnmarshalJSON(b []byte) error {
+	if len(b) == 0 {
+		return nil
+	}
+
+	s := strings.Trim(string(b), `"`)
+	tt, err := ParseISO8601(s)
+	if err != nil {
+		return err
+	}
+
+	*t = tt
+	return nil
+}
+
+// MarshalJSON writes a quoted string in the ISO8601 time format.
+func (t ISO8601) MarshalJSON() ([]byte, error) {
+	if s := t.String(); s != "" {
+		s = strconv.Quote(s)
+		return []byte(s), nil
+	}
+
+	return nullLiteral, nil // Note: if the front-end wants an empty string instead I must change that.
+}
+
+// ToTime returns the unwrapped *t to time.Time.
+func (t *ISO8601) ToTime() time.Time {
+	tt := time.Time(*t)
+	return tt
+}
+
+// IsZero reports whether "t" is zero time.
+// It completes the pg.Zeroer interface.
+func (t ISO8601) IsZero() bool {
+	return time.Time(t).IsZero()
+}
+
+// String returns the text representation of the "t" using the ISO8601 time layout.
+func (t ISO8601) String() string {
+	tt := t.ToTime()
+	if tt.IsZero() {
+		return ""
+	}
+
+	return tt.Format(ISO8601Layout)
+}
+
+// Scan completes the sql driver.Scanner interface.
+func (t *ISO8601) Scan(src interface{}) error {
+	switch v := src.(type) {
+	case time.Time: // type was set to timestamp
+		if v.IsZero() {
+			return nil // don't set zero, ignore it.
+		}
+		*t = ISO8601(v)
+	case string:
+		tt, err := ParseISO8601(v)
+		if err != nil {
+			return err
+		}
+		*t = tt
+	default:
+		return fmt.Errorf("ISO8601: unknown type of: %T", v)
+	}
+
+	return nil
+}