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|
package middleware
import (
"bytes"
"compress/gzip"
"io"
"io/ioutil"
"net/http"
"sync"
"github.com/labstack/echo/v4"
)
type (
// DecompressConfig defines the config for Decompress middleware.
DecompressConfig struct {
// Skipper defines a function to skip middleware.
Skipper Skipper
// GzipDecompressPool defines an interface to provide the sync.Pool used to create/store Gzip readers
GzipDecompressPool Decompressor
}
)
//GZIPEncoding content-encoding header if set to "gzip", decompress body contents.
const GZIPEncoding string = "gzip"
// Decompressor is used to get the sync.Pool used by the middleware to get Gzip readers
type Decompressor interface {
gzipDecompressPool() sync.Pool
}
var (
//DefaultDecompressConfig defines the config for decompress middleware
DefaultDecompressConfig = DecompressConfig{
Skipper: DefaultSkipper,
GzipDecompressPool: &DefaultGzipDecompressPool{},
}
)
// DefaultGzipDecompressPool is the default implementation of Decompressor interface
type DefaultGzipDecompressPool struct {
}
func (d *DefaultGzipDecompressPool) gzipDecompressPool() sync.Pool {
return sync.Pool{
New: func() interface{} {
// create with an empty reader (but with GZIP header)
w, err := gzip.NewWriterLevel(ioutil.Discard, gzip.BestSpeed)
if err != nil {
return err
}
b := new(bytes.Buffer)
w.Reset(b)
w.Flush()
w.Close()
r, err := gzip.NewReader(bytes.NewReader(b.Bytes()))
if err != nil {
return err
}
return r
},
}
}
//Decompress decompresses request body based if content encoding type is set to "gzip" with default config
func Decompress() echo.MiddlewareFunc {
return DecompressWithConfig(DefaultDecompressConfig)
}
//DecompressWithConfig decompresses request body based if content encoding type is set to "gzip" with config
func DecompressWithConfig(config DecompressConfig) echo.MiddlewareFunc {
// Defaults
if config.Skipper == nil {
config.Skipper = DefaultGzipConfig.Skipper
}
if config.GzipDecompressPool == nil {
config.GzipDecompressPool = DefaultDecompressConfig.GzipDecompressPool
}
return func(next echo.HandlerFunc) echo.HandlerFunc {
pool := config.GzipDecompressPool.gzipDecompressPool()
return func(c echo.Context) error {
if config.Skipper(c) {
return next(c)
}
switch c.Request().Header.Get(echo.HeaderContentEncoding) {
case GZIPEncoding:
b := c.Request().Body
i := pool.Get()
gr, ok := i.(*gzip.Reader)
if !ok {
return echo.NewHTTPError(http.StatusInternalServerError, i.(error).Error())
}
if err := gr.Reset(b); err != nil {
pool.Put(gr)
if err == io.EOF { //ignore if body is empty
return next(c)
}
return err
}
var buf bytes.Buffer
io.Copy(&buf, gr)
gr.Close()
pool.Put(gr)
b.Close() // http.Request.Body is closed by the Server, but because we are replacing it, it must be closed here
r := ioutil.NopCloser(&buf)
c.Request().Body = r
}
return next(c)
}
}
}
|
