Add URL safe 'transform.{En,De}codeBase64` variants

Adds `EncodeBase64URL` and `DecodeBase64URL` to the transform package.
Multiple times now we've run into situations where the URL variant is
necessary or the target encoder/decoder is more flexible and allows
either. This replaces a few silly collections of strings.ReplaceAll for
the other variants.

Author: terrorbyte

transform/encode.go

@@ -34,10 +34,17 @@ func Inflate(compressed []byte) ([]byte, bool) {
 	return inflated, true
 }
 
+// EncodeBase64 uses standard format non-URL safe base64 encoding to encode a string.
 func EncodeBase64(s string) string {
 	return base64.StdEncoding.EncodeToString([]byte(s))
 }
 
+// EncodeBase64URL encodes to URL safe base64 with padding.
+func EncodeBase64URL(s string) string {
+	return base64.URLEncoding.EncodeToString([]byte(s))
+}
+
+// DecodeBase64 decodes base64 with standard encoding
 func DecodeBase64(s string) string {
 	decoded, err := base64.StdEncoding.DecodeString(s)
 	if err != nil {
@@ -49,6 +56,21 @@ func DecodeBase64(s string) string {
 	return string(decoded)
 }
 
+// DecodeBase64URL decodes URL safe base64 variant.
+func DecodeBase64URL(s string) string {
+	// Internally uses the non-padded version for decoding so this will allow forcing padded
+	// data to be non-padded and support both transparently.
+	s = strings.ReplaceAll(s, `=`, ``)
+	decoded, err := base64.RawURLEncoding.DecodeString(s)
+	if err != nil {
+		output.PrintFrameworkError(err.Error())
+
+		return ""
+	}
+
+	return string(decoded)
+}
+
 func Title(s string) string {
 	return cases.Title(language.Und, cases.NoLower).String(s)
 }

transform/encode_test.go

@@ -24,6 +24,46 @@ func TestEncodeBase64(t *testing.T) {
 	t.Log(encoded)
 }
 
+func TestEncodeBase64URL(t *testing.T) {
+	encoded := EncodeBase64URL("Theskyabovetheportwasthecoloroftelevision,tunedtoadeadchannel.\xff\xff\xff\x3e\xfe\x00")
+
+	if encoded != "VGhlc2t5YWJvdmV0aGVwb3J0d2FzdGhlY29sb3JvZnRlbGV2aXNpb24sdHVuZWR0b2FkZWFkY2hhbm5lbC7___8-_gA=" {
+		t.Fatal(encoded)
+	}
+
+	t.Log(encoded)
+}
+
+func TestDecodeBase64URL(t *testing.T) {
+	decoded := DecodeBase64URL("VGhlc2t5YWJvdmV0aGVwb3J0d2FzdGhlY29sb3JvZnRlbGV2aXNpb24sdHVuZWR0b2FkZWFkY2hhbm5lbC7___8-_gA=")
+
+	if decoded != "Theskyabovetheportwasthecoloroftelevision,tunedtoadeadchannel.\xff\xff\xff\x3e\xfe\x00" {
+		t.Fatal(decoded)
+	}
+
+	t.Log(decoded)
+}
+
+func TestDecodeBase64URL_NoPad(t *testing.T) {
+	decoded := DecodeBase64URL("VGhlc2t5YWJvdmV0aGVwb3J0d2FzdGhlY29sb3JvZnRlbGV2aXNpb24sdHVuZWR0b2FkZWFkY2hhbm5lbC7___8-_gA")
+
+	if decoded != "Theskyabovetheportwasthecoloroftelevision,tunedtoadeadchannel.\xff\xff\xff\x3e\xfe\x00" {
+		t.Fatal(decoded)
+	}
+
+	t.Log(decoded)
+}
+
+func TestDecodeBase64URL_WayTooMuchPadding(t *testing.T) {
+	decoded := DecodeBase64URL("VGhlc2t5YWJvdmV0aGVwb3J0d2FzdGhlY29sb3JvZnRlbGV2aXNpb24sdHVuZWR0b2FkZWFkY2hhbm5lbC7___8-_gA=======")
+
+	if decoded != "Theskyabovetheportwasthecoloroftelevision,tunedtoadeadchannel.\xff\xff\xff\x3e\xfe\x00" {
+		t.Fatal(decoded)
+	}
+
+	t.Log(decoded)
+}
+
 func TestDecodeBase64(t *testing.T) {
 	decoded := DecodeBase64("Zm9v")