Add support for passing A1 into the digest

digest.go

@@ -27,6 +27,7 @@ type Options struct {
 	URI      string
 	GetBody  func() (io.ReadCloser, error)
 	Count    int
+	A1       string
 	Username string
 	Password string
 
@@ -76,11 +77,18 @@ func Digest(chal *Challenge, o Options) (*Credentials, error) {
 	if cred.Userhash {
 		cred.Username = hashf(h, "%s:%s", o.Username, cred.Realm)
 	}
+
+	a1 := o.A1
+
+	if a1 == "" {
+		a1 = hashf(h, "%s:%s:%s", o.Username, cred.Realm, o.Password)
+	}
+
 	// generate the response
 	switch {
 	case len(chal.QOP) == 0:
 		cred.Response = hashf(h, "%s:%s:%s",
-			hashf(h, "%s:%s:%s", o.Username, cred.Realm, o.Password), // A1
+			a1, // A1
 			cred.Nonce,
 			hashf(h, "%s:%s", o.Method, o.URI), // A2
 		)
@@ -93,7 +101,7 @@ func Digest(chal *Challenge, o Options) (*Credentials, error) {
 			cred.Nc = 1
 		}
 		cred.Response = hashf(h, "%s:%s:%08x:%s:%s:%s",
-			hashf(h, "%s:%s:%s", o.Username, cred.Realm, o.Password), // A1
+			a1, // A1
 			cred.Nonce,
 			cred.Nc,
 			cred.Cnonce,
@@ -113,7 +121,7 @@ func Digest(chal *Challenge, o Options) (*Credentials, error) {
 			return nil, fmt.Errorf("digest: failed to read body for auth-int: %w", err)
 		}
 		cred.Response = hashf(h, "%s:%s:%08x:%s:%s:%s",
-			hashf(h, "%s:%s:%s", o.Username, cred.Realm, o.Password), // A1
+			a1, // A1
 			cred.Nonce,
 			cred.Nc,
 			cred.Cnonce,

digest_test.go

@@ -1,6 +1,9 @@
 package digest
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
 	"testing"
 
 	"gotest.tools/v3/assert"
@@ -108,6 +111,35 @@ func TestDigestSHA256(t *testing.T) {
 	})
 }
 
+func TestDigestA1(t *testing.T) {
+	opt := Options{
+		Method: "GET",
+		URI:    "/dir/index.html",
+		A1:     sha265Hash("%s:%s:%s", "Mufasa", "[email protected]", "Circle of Life"),
+		Cnonce: "f2/wE4q74E6zIJEtWaHKaf5wv/H5QzzpXusqGemxURZJ",
+	}
+	chal := &Challenge{
+		Realm:     "[email protected]",
+		Nonce:     "7ypf/xlj9XXwfDPEoM4URrv/xwf94BcCAzFZH4GiTo0v",
+		Algorithm: "SHA-256",
+		Opaque:    "FQhe/qaU925kfnzjCev0ciny7QMkPqMAFRtzCUYo5tdS",
+		QOP:       []string{"auth", "auth-int"},
+	}
+	cred, err := Digest(chal, opt)
+	assert.NilError(t, err)
+	assert.DeepEqual(t, cred, &Credentials{
+		Realm:     "[email protected]",
+		Nonce:     "7ypf/xlj9XXwfDPEoM4URrv/xwf94BcCAzFZH4GiTo0v",
+		URI:       "/dir/index.html",
+		Response:  "753927fa0e85d155564e2e272a28d1802ca10daf4496794697cf8db5856cb6c1",
+		Algorithm: "SHA-256",
+		Cnonce:    "f2/wE4q74E6zIJEtWaHKaf5wv/H5QzzpXusqGemxURZJ",
+		Opaque:    "FQhe/qaU925kfnzjCev0ciny7QMkPqMAFRtzCUYo5tdS",
+		QOP:       "auth",
+		Nc:        1,
+	})
+}
+
 func TestDigestUserhash(t *testing.T) {
 	opt := Options{
 		Method:   "GET",
@@ -172,3 +204,9 @@ func TestDigestAuthInt(t *testing.T) {
 		Nc:        1,
 	})
 }
+
+func sha265Hash(format string, args ...interface{}) string {
+	h := sha256.New()
+	fmt.Fprintf(h, format, args...)
+	return hex.EncodeToString(h.Sum(nil))
+}