[chore] migrate oauth2 -> codeberg (#3857)

vendor/codeberg.org/superseriousbusiness/oauth2/v4/const.go

@@ -0,0 +1,76 @@
+package oauth2
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"strings"
+)
+
+// ResponseType the type of authorization request
+type ResponseType string
+
+// define the type of authorization request
+const (
+	Code  ResponseType = "code"
+	Token ResponseType = "token"
+)
+
+func (rt ResponseType) String() string {
+	return string(rt)
+}
+
+// GrantType authorization model
+type GrantType string
+
+// define authorization model
+const (
+	AuthorizationCode   GrantType = "authorization_code"
+	PasswordCredentials GrantType = "password"
+	ClientCredentials   GrantType = "client_credentials"
+	Refreshing          GrantType = "refresh_token"
+	Implicit            GrantType = "__implicit"
+)
+
+func (gt GrantType) String() string {
+	if gt == AuthorizationCode ||
+		gt == PasswordCredentials ||
+		gt == ClientCredentials ||
+		gt == Refreshing {
+		return string(gt)
+	}
+	return ""
+}
+
+// CodeChallengeMethod PCKE method
+type CodeChallengeMethod string
+
+const (
+	// CodeChallengePlain PCKE Method
+	CodeChallengePlain CodeChallengeMethod = "plain"
+	// CodeChallengeS256 PCKE Method
+	CodeChallengeS256 CodeChallengeMethod = "S256"
+)
+
+func (ccm CodeChallengeMethod) String() string {
+	if ccm == CodeChallengePlain ||
+		ccm == CodeChallengeS256 {
+		return string(ccm)
+	}
+	return ""
+}
+
+// Validate code challenge
+func (ccm CodeChallengeMethod) Validate(cc, ver string) bool {
+	switch ccm {
+	case CodeChallengePlain:
+		return cc == ver
+	case CodeChallengeS256:
+		s256 := sha256.Sum256([]byte(ver))
+		// trim padding
+		a := strings.TrimRight(base64.URLEncoding.EncodeToString(s256[:]), "=")
+		b := strings.TrimRight(cc, "=")
+		return a == b
+	default:
+		return false
+	}
+}