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|
package middleware
import (
"fmt"
"io"
"sync"
"github.com/labstack/echo/v4"
"github.com/labstack/gommon/bytes"
)
type (
// BodyLimitConfig defines the config for BodyLimit middleware.
BodyLimitConfig struct {
// Skipper defines a function to skip middleware.
Skipper Skipper
// Maximum allowed size for a request body, it can be specified
// as `4x` or `4xB`, where x is one of the multiple from K, M, G, T or P.
Limit string `yaml:"limit"`
limit int64
}
limitedReader struct {
BodyLimitConfig
reader io.ReadCloser
read int64
context echo.Context
}
)
var (
// DefaultBodyLimitConfig is the default BodyLimit middleware config.
DefaultBodyLimitConfig = BodyLimitConfig{
Skipper: DefaultSkipper,
}
)
// BodyLimit returns a BodyLimit middleware.
//
// BodyLimit middleware sets the maximum allowed size for a request body, if the
// size exceeds the configured limit, it sends "413 - Request Entity Too Large"
// response. The BodyLimit is determined based on both `Content-Length` request
// header and actual content read, which makes it super secure.
// Limit can be specified as `4x` or `4xB`, where x is one of the multiple from K, M,
// G, T or P.
func BodyLimit(limit string) echo.MiddlewareFunc {
c := DefaultBodyLimitConfig
c.Limit = limit
return BodyLimitWithConfig(c)
}
// BodyLimitWithConfig returns a BodyLimit middleware with config.
// See: `BodyLimit()`.
func BodyLimitWithConfig(config BodyLimitConfig) echo.MiddlewareFunc {
// Defaults
if config.Skipper == nil {
config.Skipper = DefaultBodyLimitConfig.Skipper
}
limit, err := bytes.Parse(config.Limit)
if err != nil {
panic(fmt.Errorf("echo: invalid body-limit=%s", config.Limit))
}
config.limit = limit
pool := limitedReaderPool(config)
return func(next echo.HandlerFunc) echo.HandlerFunc {
return func(c echo.Context) error {
if config.Skipper(c) {
return next(c)
}
req := c.Request()
// Based on content length
if req.ContentLength > config.limit {
return echo.ErrStatusRequestEntityTooLarge
}
// Based on content read
r := pool.Get().(*limitedReader)
r.Reset(req.Body, c)
defer pool.Put(r)
req.Body = r
return next(c)
}
}
}
func (r *limitedReader) Read(b []byte) (n int, err error) {
n, err = r.reader.Read(b)
r.read += int64(n)
if r.read > r.limit {
return n, echo.ErrStatusRequestEntityTooLarge
}
return
}
func (r *limitedReader) Close() error {
return r.reader.Close()
}
func (r *limitedReader) Reset(reader io.ReadCloser, context echo.Context) {
r.reader = reader
r.context = context
r.read = 0
}
func limitedReaderPool(c BodyLimitConfig) sync.Pool {
return sync.Pool{
New: func() interface{} {
return &limitedReader{BodyLimitConfig: c}
},
}
}
|
