gotosocial/internal/middleware/ratelimit.go

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/*
GoToSocial
Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
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"
"net/http"
"time"
"github.com/gin-gonic/gin"
"github.com/ulule/limiter/v3"
limitergin "github.com/ulule/limiter/v3/drivers/middleware/gin"
"github.com/ulule/limiter/v3/drivers/store/memory"
)
const rateLimitPeriod = 5 * time.Minute
// RateLimit returns a gin middleware that will automatically rate limit caller (by IP address),
// and enrich the response header with the following headers:
//
// - `x-ratelimit-limit` - maximum number of requests allowed per time period (fixed).
// - `x-ratelimit-remaining` - number of remaining requests that can still be performed.
// - `x-ratelimit-reset` - unix timestamp when the rate limit will reset.
//
// If `x-ratelimit-limit` is exceeded, the request is aborted and an HTTP 429 TooManyRequests
// status is returned.
//
// If the config AdvancedRateLimitRequests value is <= 0, then a noop handler will be returned,
// which performs no rate limiting.
func RateLimit(limit int) gin.HandlerFunc {
if limit <= 0 {
// use noop middleware if ratelimiting is disabled
return func(ctx *gin.Context) {}
}
limiter := limiter.New(
memory.NewStore(),
limiter.Rate{Period: rateLimitPeriod, Limit: int64(limit)},
limiter.WithIPv6Mask(net.CIDRMask(64, 128)), // apply /64 mask to IPv6 addresses
)
// use custom rate limit reached error
handler := func(c *gin.Context) {
c.AbortWithStatusJSON(http.StatusTooManyRequests, gin.H{"error": "rate limit reached"})
}
return limitergin.NewMiddleware(
limiter,
limitergin.WithLimitReachedHandler(handler),
)
}