Refactor cookie building and parsing

Extracts buildCookieValue() and parseCookieValue() from OauthProxy.ServeHTTP()
and adds tests for both.

cookies.go

@@ -97,3 +97,34 @@ func decodeAccessToken(aes_cipher cipher.Block, encoded_access_token string) (st
 
 	return string(encrypted_access_token), nil
 }
+
+func buildCookieValue(email string, aes_cipher cipher.Block,
+	access_token string) (string, error) {
+	if aes_cipher == nil {
+		return email, nil
+	}
+
+	encoded_token, err := encodeAccessToken(aes_cipher, access_token)
+	if err != nil {
+		return email, fmt.Errorf(
+			"error encoding access token for %s: %s", email, err)
+	}
+	return email + "|" + encoded_token, nil
+}
+
+func parseCookieValue(value string, aes_cipher cipher.Block) (email, user,
+	access_token string, err error) {
+	components := strings.Split(value, "|")
+	email = components[0]
+	user = strings.Split(email, "@")[0]
+
+	if aes_cipher != nil && len(components) == 2 {
+		access_token, err = decodeAccessToken(aes_cipher, components[1])
+		if err != nil {
+			err = fmt.Errorf(
+				"error decoding access token for %s: %s",
+				email, err)
+		}
+	}
+	return email, user, access_token, err
+}

cookies_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"crypto/aes"
 	"github.com/bmizerany/assert"
+	"strings"
 	"testing"
 )
 
@@ -21,3 +22,54 @@ func TestEncodeAndDecodeAccessToken(t *testing.T) {
 	assert.NotEqual(t, access_token, encoded_token)
 	assert.Equal(t, access_token, decoded_token)
 }
+
+func TestBuildCookieValueWithoutAccessToken(t *testing.T) {
+	value, err := buildCookieValue("michael.bland@gsa.gov", nil, "")
+	assert.Equal(t, nil, err)
+	assert.Equal(t, "michael.bland@gsa.gov", value)
+}
+
+func TestBuildCookieValueWithAccessTokenAndNilCipher(t *testing.T) {
+	value, err := buildCookieValue("michael.bland@gsa.gov", nil,
+		"access token")
+	assert.Equal(t, nil, err)
+	assert.Equal(t, "michael.bland@gsa.gov", value)
+}
+
+func TestParseCookieValueWithoutAccessToken(t *testing.T) {
+	email, user, access_token, err := parseCookieValue(
+		"michael.bland@gsa.gov", nil)
+	assert.Equal(t, nil, err)
+	assert.Equal(t, "michael.bland@gsa.gov", email)
+	assert.Equal(t, "michael.bland", user)
+	assert.Equal(t, "", access_token)
+}
+
+func TestParseCookieValueWithAccessTokenAndNilCipher(t *testing.T) {
+	email, user, access_token, err := parseCookieValue(
+		"michael.bland@gsa.gov|access_token", nil)
+	assert.Equal(t, nil, err)
+	assert.Equal(t, "michael.bland@gsa.gov", email)
+	assert.Equal(t, "michael.bland", user)
+	assert.Equal(t, "", access_token)
+}
+
+func TestBuildAndParseCookieValueWithAccessToken(t *testing.T) {
+	aes_cipher, err := aes.NewCipher([]byte("0123456789abcdef"))
+	assert.Equal(t, nil, err)
+	value, err := buildCookieValue("michael.bland@gsa.gov", aes_cipher,
+		"access_token")
+	assert.Equal(t, nil, err)
+
+	prefix := "michael.bland@gsa.gov|"
+	if !strings.HasPrefix(value, prefix) {
+		t.Fatal("cookie value does not start with \"%s\": %s",
+			prefix, value)
+	}
+
+	email, user, access_token, err := parseCookieValue(value, aes_cipher)
+	assert.Equal(t, nil, err)
+	assert.Equal(t, "michael.bland@gsa.gov", email)
+	assert.Equal(t, "michael.bland", user)
+	assert.Equal(t, "access_token", access_token)
+}

oauthproxy.go

@@ -425,20 +425,12 @@ func (p *OauthProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 		// set cookie, or deny
 		if p.Validator(email) {
 			log.Printf("%s authenticating %s completed", remoteAddr, email)
-			encoded_token := ""
-			if p.AesCipher != nil {
-				encoded_token, err = encodeAccessToken(p.AesCipher, access_token)
-				if err != nil {
-					log.Printf("error encoding access token: %s", err)
-				}
-			}
-			access_token = ""
-
-			if encoded_token != "" {
-				p.SetCookie(rw, req, email+"|"+encoded_token)
-			} else {
-				p.SetCookie(rw, req, email)
+			value, err := buildCookieValue(
+				email, p.AesCipher, access_token)
+			if err != nil {
+				log.Printf(err.Error())
 			}
+			p.SetCookie(rw, req, value)
 			http.Redirect(rw, req, redirect, 302)
 			return
 		} else {
@@ -452,15 +444,13 @@ func (p *OauthProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 		if err == nil {
 			var value string
 			value, ok = validateCookie(cookie, p.CookieSeed)
-			components := strings.Split(value, "|")
-			email = components[0]
-			if len(components) == 2 {
-				access_token, err = decodeAccessToken(p.AesCipher, components[1])
+			if ok {
+				email, user, access_token, err = parseCookieValue(
+					value, p.AesCipher)
 				if err != nil {
-					log.Printf("error decoding access token: %s", err)
+					log.Printf(err.Error())
 				}
 			}
-			user = strings.Split(email, "@")[0]
 		}
 	}