fix: use the same schema encoder everywhere (#299)

properly register SpaceDelimitedArray for all instances
of schema.Encoder inside the oidc framework.

Closes #295

pkg/oidc/types.go

@@ -4,9 +4,11 @@ import (
 	"database/sql/driver"
 	"encoding/json"
 	"fmt"
+	"reflect"
 	"strings"
 	"time"
 
+	"github.com/gorilla/schema"
 	"golang.org/x/text/language"
 	"gopkg.in/square/go-jose.v2"
 )
@@ -125,6 +127,16 @@ func (s SpaceDelimitedArray) Value() (driver.Value, error) {
 	return strings.Join(s, " "), nil
 }
 
+// NewEncoder returns a schema Encoder with
+// a registered encoder for SpaceDelimitedArray.
+func NewEncoder() *schema.Encoder {
+	e := schema.NewEncoder()
+	e.RegisterEncoder(SpaceDelimitedArray{}, func(value reflect.Value) string {
+		return value.Interface().(SpaceDelimitedArray).Encode()
+	})
+	return e
+}
+
 type Time time.Time
 
 func (t *Time) UnmarshalJSON(data []byte) error {

pkg/oidc/types_test.go

@@ -3,10 +3,12 @@ package oidc
 import (
 	"bytes"
 	"encoding/json"
+	"net/url"
 	"strconv"
 	"strings"
 	"testing"
 
+	"github.com/gorilla/schema"
 	"github.com/stretchr/testify/assert"
 	"golang.org/x/text/language"
 )
@@ -335,3 +337,20 @@ func TestSpaceDelimitatedArray_ValuerNil(t *testing.T) {
 		assert.Equal(t, SpaceDelimitedArray(nil), reversed, "scan nil")
 	}
 }
+
+func TestNewEncoder(t *testing.T) {
+	type request struct {
+		Scopes SpaceDelimitedArray `schema:"scope"`
+	}
+	a := request{
+		Scopes: SpaceDelimitedArray{"foo", "bar"},
+	}
+
+	values := make(url.Values)
+	NewEncoder().Encode(a, values)
+	assert.Equal(t, url.Values{"scope": []string{"foo bar"}}, values)
+
+	var b request
+	schema.NewDecoder().Decode(&b, values)
+	assert.Equal(t, a, b)
+}