authenticate: fix expiring user info endpoint (#2976)

* authenticate: fix expiring user info endpoint

* add test

authenticate/url_test.go

@@ -0,0 +1,52 @@
+package authenticate
+
+import (
+	"net/http"
+	"net/url"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/pomerium/pomerium/internal/urlutil"
+)
+
+func TestAuthenticate_getRedirectURI(t *testing.T) {
+	t.Run("query", func(t *testing.T) {
+		r, err := http.NewRequest("GET", "https://www.example.com?"+(url.Values{
+			urlutil.QueryRedirectURI: {"https://www.example.com/redirect"},
+		}).Encode(), nil)
+		require.NoError(t, err)
+
+		a := new(Authenticate)
+		redirectURI, ok := a.getRedirectURI(r)
+		assert.True(t, ok)
+		assert.Equal(t, "https://www.example.com/redirect", redirectURI)
+	})
+	t.Run("form", func(t *testing.T) {
+		r, err := http.NewRequest("POST", "https://www.example.com", strings.NewReader((url.Values{
+			urlutil.QueryRedirectURI: {"https://www.example.com/redirect"},
+		}).Encode()))
+		require.NoError(t, err)
+		r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+		a := new(Authenticate)
+		redirectURI, ok := a.getRedirectURI(r)
+		assert.True(t, ok)
+		assert.Equal(t, "https://www.example.com/redirect", redirectURI)
+	})
+	t.Run("cookie", func(t *testing.T) {
+		r, err := http.NewRequest("GET", "https://www.example.com", nil)
+		require.NoError(t, err)
+		r.AddCookie(&http.Cookie{
+			Name:  urlutil.QueryRedirectURI,
+			Value: "https://www.example.com/redirect",
+		})
+
+		a := new(Authenticate)
+		redirectURI, ok := a.getRedirectURI(r)
+		assert.True(t, ok)
+		assert.Equal(t, "https://www.example.com/redirect", redirectURI)
+	})
+}