fix: parse Authorization header case-insensitively and support token format (#137)

## Summary
- Make auth header parsing RFC 7235 compliant by comparing the scheme case-insensitively (`bearer`, `BEARER`, etc. all work now)
- Add support for Gitea-style `token <value>` format in addition to `Bearer <value>`

Fixes https://gitea.com/gitea/gitea-mcp/issues/59

---
*This PR was authored by Claude.*

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/137
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-committed-by: silverwind <me@silverwind.io>

operation/operation.go

@@ -67,21 +67,25 @@ func RegisterTool(s *server.MCPServer) {
 	s.DeleteTools("")
 }
 
-// parseBearerToken extracts the Bearer token from an Authorization header.
+// parseAuthToken extracts the token from an Authorization header.
+// Supports "Bearer <token>" (case-insensitive per RFC 7235) and
+// Gitea-style "token <token>" formats.
 // Returns the token and true if valid, empty string and false otherwise.
-func parseBearerToken(authHeader string) (string, bool) {
+func parseAuthToken(authHeader string) (string, bool) {
-	const bearerPrefix = "Bearer "
+	if len(authHeader) > 7 && strings.EqualFold(authHeader[:7], "Bearer ") {
-	if len(authHeader) < len(bearerPrefix) || !strings.HasPrefix(authHeader, bearerPrefix) {
+		token := strings.TrimSpace(authHeader[7:])
-		return "", false
+		if token != "" {
-	}
-
-	token := strings.TrimSpace(authHeader[len(bearerPrefix):])
-	if token == "" {
-		return "", false
-	}
-
 			return token, true
 		}
+	}
+	if len(authHeader) > 6 && strings.EqualFold(authHeader[:6], "token ") {
+		token := strings.TrimSpace(authHeader[6:])
+		if token != "" {
+			return token, true
+		}
+	}
+	return "", false
+}
 
 func getContextWithToken(ctx context.Context, r *http.Request) context.Context {
 	authHeader := r.Header.Get("Authorization")
@@ -89,7 +93,7 @@ func getContextWithToken(ctx context.Context, r *http.Request) context.Context {
 		return ctx
 	}
 
-	token, ok := parseBearerToken(authHeader)
+	token, ok := parseAuthToken(authHeader)
 	if !ok {
 		return ctx
 	}

operation/operation_test.go

@@ -4,7 +4,7 @@ import (
 	"testing"
 )
 
-func TestParseBearerToken(t *testing.T) {
+func TestParseAuthToken(t *testing.T) {
 	tests := []struct {
 		name      string
 		header    string
@@ -12,23 +12,29 @@ func TestParseBearerToken(t *testing.T) {
 		wantOK    bool
 	}{
 		{
-			name:      "valid token",
+			name:      "valid Bearer token",
 			header:    "Bearer validtoken",
 			wantToken: "validtoken",
 			wantOK:    true,
 		},
+		{
+			name:      "lowercase bearer",
+			header:    "bearer lowercase",
+			wantToken: "lowercase",
+			wantOK:    true,
+		},
+		{
+			name:      "uppercase BEARER",
+			header:    "BEARER uppercase",
+			wantToken: "uppercase",
+			wantOK:    true,
+		},
 		{
 			name:      "token with spaces trimmed",
 			header:    "Bearer   spacedToken ",
 			wantToken: "spacedToken",
 			wantOK:    true,
 		},
-		{
-			name:      "lowercase bearer should fail",
-			header:    "bearer lowercase",
-			wantToken: "",
-			wantOK:    false,
-		},
 		{
 			name:      "bearer with no token",
 			header:    "Bearer ",
@@ -47,6 +53,24 @@ func TestParseBearerToken(t *testing.T) {
 			wantToken: "",
 			wantOK:    false,
 		},
+		{
+			name:      "Gitea token format",
+			header:    "token giteaapitoken",
+			wantToken: "giteaapitoken",
+			wantOK:    true,
+		},
+		{
+			name:      "Gitea Token format capitalized",
+			header:    "Token giteaapitoken",
+			wantToken: "giteaapitoken",
+			wantOK:    true,
+		},
+		{
+			name:      "token with no value",
+			header:    "token ",
+			wantToken: "",
+			wantOK:    false,
+		},
 		{
 			name:      "different auth type",
 			header:    "Basic dXNlcjpwYXNz",
@@ -60,7 +84,7 @@ func TestParseBearerToken(t *testing.T) {
 			wantOK:    false,
 		},
 		{
-			name:      "token with internal spaces",
+			name:      "bearer token with internal spaces",
 			header:    "Bearer token with spaces",
 			wantToken: "token with spaces",
 			wantOK:    true,
@@ -69,12 +93,12 @@ func TestParseBearerToken(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			gotToken, gotOK := parseBearerToken(tt.header)
+			gotToken, gotOK := parseAuthToken(tt.header)
 			if gotToken != tt.wantToken {
-				t.Errorf("parseBearerToken() token = %q, want %q", gotToken, tt.wantToken)
+				t.Errorf("parseAuthToken() token = %q, want %q", gotToken, tt.wantToken)
 			}
 			if gotOK != tt.wantOK {
-				t.Errorf("parseBearerToken() ok = %v, want %v", gotOK, tt.wantOK)
+				t.Errorf("parseAuthToken() ok = %v, want %v", gotOK, tt.wantOK)
 			}
 		})
 	}