1 files changed, 62 insertions, 0 deletions
diff --git a/internal/httpclient/validate.go b/internal/httpclient/validate.go
new file mode 100644
index 000000000..881d3f699
--- /dev/null
+++ b/internal/httpclient/validate.go
@@ -0,0 +1,62 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package httpclient
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"golang.org/x/net/http/httpguts"
+)
+
+// ValidateRequest performs the same request validation logic found in the default
+// net/http.Transport{}.roundTrip() function, but pulls it out into this separate
+// function allowing validation errors to be wrapped under a single error type.
+func ValidateRequest(r *http.Request) error {
+	switch {
+	case r.URL == nil:
+		return fmt.Errorf("%w: nil url", ErrInvalidRequest)
+	case r.Header == nil:
+		return fmt.Errorf("%w: nil header", ErrInvalidRequest)
+	case r.URL.Host == "":
+		return fmt.Errorf("%w: empty url host", ErrInvalidRequest)
+	case r.URL.Scheme != "http" && r.URL.Scheme != "https":
+		return fmt.Errorf("%w: unsupported protocol %q", ErrInvalidRequest, r.URL.Scheme)
+	case strings.IndexFunc(r.Method, func(r rune) bool { return !httpguts.IsTokenRune(r) }) != -1:
+		return fmt.Errorf("%w: invalid method %q", ErrInvalidRequest, r.Method)
+	}
+
+	for key, values := range r.Header {
+		// Check field key name is valid
+		if !httpguts.ValidHeaderFieldName(key) {
+			return fmt.Errorf("%w: invalid header field name %q", ErrInvalidRequest, key)
+		}
+
+		// Check each field value is valid
+		for i := 0; i < len(values); i++ {
+			if !httpguts.ValidHeaderFieldValue(values[i]) {
+				return fmt.Errorf("%w: invalid header field value %q", ErrInvalidRequest, values[i])
+			}
+		}
+	}
+
+	// ps. kim wrote this
+
+	return nil
+}