gotosocial/internal/middleware/useragent.go

69 lines
2 KiB
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 (
"net/http"
apiutil "code.superseriousbusiness.org/gotosocial/internal/api/util"
"code.superseriousbusiness.org/gotosocial/internal/config"
"code.superseriousbusiness.org/gotosocial/internal/log"
"github.com/gin-gonic/gin"
)
// UserAgentOrTeapot returns a gin middleware
// which aborts requests with empty user agent
// strings, returning code 418 - I'm a teapot.
//
// If `instance-reject-empty-user-agents` is
// false, it just logs a debug msg instead.
func UserAgentOrTeapot() gin.HandlerFunc {
// Build variables outside the handler
// so they're not instantiated every
// time a request is processed.
var (
rsp = []byte(`{"error": "I'm a teapot: no user-agent sent with request"}`)
rejectEmpty = config.GetInstanceRejectEmptyUserAgents()
)
return func(c *gin.Context) {
ua := c.Request.UserAgent()
if ua != "" {
// All good.
return
}
if !rejectEmpty {
// No user-agent was
// set but that's OK.
log.Debugf(
c.Request.Context(),
"allowing request with empty User-Agent from client %s",
c.ClientIP(),
)
return
}
// No user-agent set and that's not ok!
//
// Give them a taste of the ol' teapot.
apiutil.Data(c, http.StatusTeapot, apiutil.AppJSON, rsp)
c.Abort()
}
}