v0.1.0 initial commit, auth features extracted from logwisp to be a standalone utility package

http.go

@@ -0,0 +1,61 @@
+// FILE: auth/http.go
+package auth
+
+import (
+	"encoding/base64"
+	"strings"
+)
+
+// ParseBasicAuth extracts username/password from Basic auth header
+func ParseBasicAuth(header string) (username, password string, err error) {
+	const prefix = "Basic "
+	if !strings.HasPrefix(header, prefix) {
+		return "", "", ErrAuthInvalidBasicFormat
+	}
+
+	encoded := strings.TrimPrefix(header, prefix)
+	decoded, err := base64.StdEncoding.DecodeString(encoded)
+	if err != nil {
+		return "", "", ErrAuthInvalidBasicEncoding
+	}
+
+	credentials := string(decoded)
+	idx := strings.IndexByte(credentials, ':')
+	if idx < 0 {
+		return "", "", ErrAuthInvalidBasicCreds
+	}
+
+	return credentials[:idx], credentials[idx+1:], nil
+}
+
+// ParseBearerToken extracts token from Bearer auth header
+func ParseBearerToken(header string) (token string, err error) {
+	const prefix = "Bearer "
+	if !strings.HasPrefix(header, prefix) {
+		return "", ErrAuthInvalidBearerFormat
+	}
+
+	token = strings.TrimPrefix(header, prefix)
+	if token == "" {
+		return "", ErrAuthEmptyBearerToken
+	}
+
+	return token, nil
+}
+
+// ExtractAuthType returns authentication type from header
+func ExtractAuthType(header string) string {
+	if strings.HasPrefix(header, "Basic ") {
+		return "Basic"
+	}
+	if strings.HasPrefix(header, "Bearer ") {
+		return "Bearer"
+	}
+
+	// Extract first word as auth type
+	idx := strings.IndexByte(header, ' ')
+	if idx > 0 {
+		return header[:idx]
+	}
+	return ""
+}