GoToSocial/internal/middleware/useragent.go

// 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 middleware

import (
	"errors"
	"net/http"

	"github.com/gin-gonic/gin"
)

// UserAgent returns a gin middleware which aborts requests with
// empty user agent strings, returning code 418 - I'm a teapot.
func UserAgent() gin.HandlerFunc {
	// todo: make this configurable
	return func(c *gin.Context) {
		if ua := c.Request.UserAgent(); ua == "" {
			code := http.StatusTeapot
			err := errors.New(http.StatusText(code) + ": no user-agent sent with request")
			c.AbortWithStatusJSON(code, gin.H{"error": err.Error()})
		}
	}
}