package compress import ( "context" "fmt" "mime" "net/http" "slices" "strings" "github.com/klauspost/compress/gzhttp" "github.com/traefik/traefik/v3/pkg/config/dynamic" "github.com/traefik/traefik/v3/pkg/middlewares" "github.com/traefik/traefik/v3/pkg/middlewares/compress/brotli" "go.opentelemetry.io/otel/trace" ) const typeName = "Compress" // DefaultMinSize is the default minimum size (in bytes) required to enable compression. // See https://github.com/klauspost/compress/blob/9559b037e79ad673c71f6ef7c732c00949014cd2/gzhttp/compress.go#L47. const DefaultMinSize = 1024 // Compress is a middleware that allows to compress the response. type compress struct { next http.Handler name string excludes []string minSize int brotliHandler http.Handler gzipHandler http.Handler } // New creates a new compress middleware. func New(ctx context.Context, next http.Handler, conf dynamic.Compress, name string) (http.Handler, error) { middlewares.GetLogger(ctx, name, typeName).Debug().Msg("Creating middleware") excludes := []string{"application/grpc"} for _, v := range conf.ExcludedContentTypes { mediaType, _, err := mime.ParseMediaType(v) if err != nil { return nil, err } excludes = append(excludes, mediaType) } minSize := DefaultMinSize if conf.MinResponseBodyBytes > 0 { minSize = conf.MinResponseBodyBytes } c := &compress{ next: next, name: name, excludes: excludes, minSize: minSize, } var err error c.brotliHandler, err = c.newBrotliHandler() if err != nil { return nil, err } c.gzipHandler, err = c.newGzipHandler() if err != nil { return nil, err } return c, nil } func (c *compress) ServeHTTP(rw http.ResponseWriter, req *http.Request) { logger := middlewares.GetLogger(req.Context(), c.name, typeName) if req.Method == http.MethodHead { c.next.ServeHTTP(rw, req) return } mediaType, _, err := mime.ParseMediaType(req.Header.Get("Content-Type")) if err != nil { logger.Debug().Err(err).Msg("Unable to parse MIME type") } // Notably for text/event-stream requests the response should not be compressed. // See https://github.com/traefik/traefik/issues/2576 if slices.Contains(c.excludes, mediaType) { c.next.ServeHTTP(rw, req) return } // Client doesn't specify a preferred encoding, for compatibility don't encode the request // See https://github.com/traefik/traefik/issues/9734 acceptEncoding, ok := req.Header["Accept-Encoding"] if !ok { c.next.ServeHTTP(rw, req) return } if encodingAccepts(acceptEncoding, "br") { c.brotliHandler.ServeHTTP(rw, req) return } if encodingAccepts(acceptEncoding, "gzip") { c.gzipHandler.ServeHTTP(rw, req) return } c.next.ServeHTTP(rw, req) } func (c *compress) GetTracingInformation() (string, string, trace.SpanKind) { return c.name, typeName, trace.SpanKindInternal } func (c *compress) newGzipHandler() (http.Handler, error) { wrapper, err := gzhttp.NewWrapper( gzhttp.ExceptContentTypes(c.excludes), gzhttp.MinSize(c.minSize), ) if err != nil { return nil, fmt.Errorf("new gzip wrapper: %w", err) } return wrapper(c.next), nil } func (c *compress) newBrotliHandler() (http.Handler, error) { cfg := brotli.Config{ ExcludedContentTypes: c.excludes, MinSize: c.minSize, } wrapper, err := brotli.NewWrapper(cfg) if err != nil { return nil, fmt.Errorf("new brotli wrapper: %w", err) } return wrapper(c.next), nil } func encodingAccepts(acceptEncoding []string, typ string) bool { for _, ae := range acceptEncoding { for _, e := range strings.Split(ae, ",") { parsed := strings.Split(strings.TrimSpace(e), ";") if len(parsed) == 0 { continue } if parsed[0] == typ || parsed[0] == "*" { return true } } } return false }