GODT-980: placeholder for user agent

internal/config/useragent/useragent.go

@@ -0,0 +1,59 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge 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 General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package useragent
+
+import (
+	"fmt"
+	"regexp"
+	"runtime"
+)
+
+type UserAgent struct {
+	client, platform string
+}
+
+func New() *UserAgent {
+	return &UserAgent{
+		client:   "",
+		platform: runtime.GOOS,
+	}
+}
+
+func (ua *UserAgent) SetClient(name, version string) {
+	ua.client = fmt.Sprintf("%v/%v", name, regexp.MustCompile(`(.*) \((.*)\)`).ReplaceAllString(version, "$1-$2"))
+}
+
+func (ua *UserAgent) HasClient() bool {
+	return ua.client != ""
+}
+
+func (ua *UserAgent) SetPlatform(platform string) {
+	ua.platform = platform
+}
+
+func (ua *UserAgent) String() string {
+	var client string
+
+	if ua.client != "" {
+		client = ua.client
+	} else {
+		client = "NoClient/0.0.1"
+	}
+
+	return fmt.Sprintf("%v (%v)", client, ua.platform)
+}