package middleware import ( "compress/gzip" "io" "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{} { return new(gzip.Reader) }} } //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) } if c.Request().Header.Get(echo.HeaderContentEncoding) != GZIPEncoding { return next(c) } i := pool.Get() gr, ok := i.(*gzip.Reader) if !ok || gr == nil { return echo.NewHTTPError(http.StatusInternalServerError, i.(error).Error()) } defer pool.Put(gr) b := c.Request().Body defer b.Close() if err := gr.Reset(b); err != nil { if err == io.EOF { //ignore if body is empty return next(c) } return err } // only Close gzip reader if it was set to a proper gzip source otherwise it will panic on close. defer gr.Close() c.Request().Body = gr return next(c) } } }