Merge pull request #280 from 56quarters/duration-json

Add methods to model.Duration for JSON marshalling and unmarshalling

model/time.go

@@ -14,6 +14,7 @@
 package model
 
 import (
+	"encoding/json"
 	"fmt"
 	"math"
 	"regexp"
@@ -254,6 +255,25 @@ func (d Duration) String() string {
 	return r
 }
 
+// MarshalJSON implements the json.Marshaler interface.
+func (d Duration) MarshalJSON() ([]byte, error) {
+	return json.Marshal(d.String())
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (d *Duration) UnmarshalJSON(bytes []byte) error {
+	var s string
+	if err := json.Unmarshal(bytes, &s); err != nil {
+		return err
+	}
+	dur, err := ParseDuration(s)
+	if err != nil {
+		return err
+	}
+	*d = dur
+	return nil
+}
+
 // MarshalText implements the encoding.TextMarshaler interface.
 func (d *Duration) MarshalText() ([]byte, error) {
 	return []byte(d.String()), nil

model/time_test.go

@@ -14,6 +14,7 @@
 package model
 
 import (
+	"encoding/json"
 	"strconv"
 	"testing"
 	"time"
@@ -230,6 +231,82 @@ func TestDuration_UnmarshalText(t *testing.T) {
 	}
 }
 
+func TestDuration_UnmarshalJSON(t *testing.T) {
+	var cases = []struct {
+		in  string
+		out time.Duration
+
+		expectedString string
+	}{
+		{
+			in:             `"0"`,
+			out:            0,
+			expectedString: `"0s"`,
+		}, {
+			in:             `"0w"`,
+			out:            0,
+			expectedString: `"0s"`,
+		}, {
+			in:  `"0s"`,
+			out: 0,
+		}, {
+			in:  `"324ms"`,
+			out: 324 * time.Millisecond,
+		}, {
+			in:  `"3s"`,
+			out: 3 * time.Second,
+		}, {
+			in:  `"5m"`,
+			out: 5 * time.Minute,
+		}, {
+			in:  `"1h"`,
+			out: time.Hour,
+		}, {
+			in:  `"4d"`,
+			out: 4 * 24 * time.Hour,
+		}, {
+			in:  `"4d1h"`,
+			out: 4*24*time.Hour + time.Hour,
+		}, {
+			in:             `"14d"`,
+			out:            14 * 24 * time.Hour,
+			expectedString: `"2w"`,
+		}, {
+			in:  `"3w"`,
+			out: 3 * 7 * 24 * time.Hour,
+		}, {
+			in:             `"3w2d1h"`,
+			out:            3*7*24*time.Hour + 2*24*time.Hour + time.Hour,
+			expectedString: `"23d1h"`,
+		}, {
+			in:  `"10y"`,
+			out: 10 * 365 * 24 * time.Hour,
+		},
+	}
+
+	for _, c := range cases {
+		var d Duration
+		err := json.Unmarshal([]byte(c.in), &d)
+		if err != nil {
+			t.Errorf("Unexpected error on input %q", c.in)
+		}
+		if time.Duration(d) != c.out {
+			t.Errorf("Expected %v but got %v", c.out, d)
+		}
+		expectedString := c.expectedString
+		if c.expectedString == "" {
+			expectedString = c.in
+		}
+		bytes, err := json.Marshal(d)
+		if err != nil {
+			t.Errorf("Unexpected error on marshal of %v: %s", d, err)
+		}
+		if string(bytes) != expectedString {
+			t.Errorf("Expected duration string %q but got %q", c.in, d.String())
+		}
+	}
+}
+
 func TestParseBadDuration(t *testing.T) {
 	var cases = []string{
 		"1",