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builder.go
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builder.go
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// Copyright 2023 igevin
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ratelimit
import (
_ "embed"
"fmt"
"github.com/gin-gonic/gin"
"github.com/redis/go-redis/v9"
"log"
"net/http"
"time"
)
type Builder struct {
prefix string
cmd redis.Cmdable
interval time.Duration
rate int
}
//go:embed slide_window.lua
var luaScript string
func NewBuilder(cmd redis.Cmdable, interval time.Duration, rate int) *Builder {
return &Builder{
prefix: "ip-limiter",
cmd: cmd,
interval: interval,
rate: rate,
}
}
func (b *Builder) Prefix(prefix string) *Builder {
b.prefix = prefix
return b
}
func (b *Builder) Build() gin.HandlerFunc {
return func(ctx *gin.Context) {
limited, err := b.limit(ctx)
if err != nil {
log.Println(err)
ctx.AbortWithStatus(http.StatusInternalServerError)
return
}
if limited {
ctx.AbortWithStatus(http.StatusTooManyRequests)
return
}
ctx.Next()
}
}
func (b *Builder) limit(ctx *gin.Context) (bool, error) {
key := fmt.Sprintf("%s:%s", b.prefix, ctx.ClientIP())
return b.cmd.Eval(ctx, luaScript, []string{key},
b.interval.Milliseconds(), b.rate, time.Now().UnixMilli()).Bool()
}