Adding upstream version 0.28.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

apis/middlewares_gzip.go

@@ -0,0 +1,247 @@
+package apis
+
+// -------------------------------------------------------------------
+// This middleware is ported from echo/middleware to minimize the breaking
+// changes and differences in the API behavior from earlier PocketBase versions
+// (https://github.com/labstack/echo/blob/ec5b858dab6105ab4c3ed2627d1ebdfb6ae1ecb8/middleware/compress.go).
+// -------------------------------------------------------------------
+
+import (
+	"bufio"
+	"bytes"
+	"compress/gzip"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+	"sync"
+
+	"github.com/pocketbase/pocketbase/core"
+	"github.com/pocketbase/pocketbase/tools/hook"
+	"github.com/pocketbase/pocketbase/tools/router"
+)
+
+const (
+	gzipScheme = "gzip"
+)
+
+const (
+	DefaultGzipMiddlewareId = "pbGzip"
+)
+
+// GzipConfig defines the config for Gzip middleware.
+type GzipConfig struct {
+	// Gzip compression level.
+	// Optional. Default value -1.
+	Level int
+
+	// Length threshold before gzip compression is applied.
+	// Optional. Default value 0.
+	//
+	// Most of the time you will not need to change the default. Compressing
+	// a short response might increase the transmitted data because of the
+	// gzip format overhead. Compressing the response will also consume CPU
+	// and time on the server and the client (for decompressing). Depending on
+	// your use case such a threshold might be useful.
+	//
+	// See also:
+	// https://webmasters.stackexchange.com/questions/31750/what-is-recommended-minimum-object-size-for-gzip-performance-benefits
+	MinLength int
+}
+
+// Gzip returns a middleware which compresses HTTP response using Gzip compression scheme.
+func Gzip() *hook.Handler[*core.RequestEvent] {
+	return GzipWithConfig(GzipConfig{})
+}
+
+// GzipWithConfig returns a middleware which compresses HTTP response using gzip compression scheme.
+func GzipWithConfig(config GzipConfig) *hook.Handler[*core.RequestEvent] {
+	if config.Level < -2 || config.Level > 9 { // these are consts: gzip.HuffmanOnly and gzip.BestCompression
+		panic(errors.New("invalid gzip level"))
+	}
+	if config.Level == 0 {
+		config.Level = -1
+	}
+	if config.MinLength < 0 {
+		config.MinLength = 0
+	}
+
+	pool := sync.Pool{
+		New: func() interface{} {
+			w, err := gzip.NewWriterLevel(io.Discard, config.Level)
+			if err != nil {
+				return err
+			}
+			return w
+		},
+	}
+
+	bpool := sync.Pool{
+		New: func() interface{} {
+			b := &bytes.Buffer{}
+			return b
+		},
+	}
+
+	return &hook.Handler[*core.RequestEvent]{
+		Id: DefaultGzipMiddlewareId,
+		Func: func(e *core.RequestEvent) error {
+			e.Response.Header().Add("Vary", "Accept-Encoding")
+			if strings.Contains(e.Request.Header.Get("Accept-Encoding"), gzipScheme) {
+				w, ok := pool.Get().(*gzip.Writer)
+				if !ok {
+					return e.InternalServerError("", errors.New("failed to get gzip.Writer"))
+				}
+
+				rw := e.Response
+				w.Reset(rw)
+
+				buf := bpool.Get().(*bytes.Buffer)
+				buf.Reset()
+
+				grw := &gzipResponseWriter{Writer: w, ResponseWriter: rw, minLength: config.MinLength, buffer: buf}
+				defer func() {
+					// There are different reasons for cases when we have not yet written response to the client and now need to do so.
+					// a) handler response had only response code and no response body (ala 404 or redirects etc). Response code need to be written now.
+					// b) body is shorter than our minimum length threshold and being buffered currently and needs to be written
+					if !grw.wroteBody {
+						if rw.Header().Get("Content-Encoding") == gzipScheme {
+							rw.Header().Del("Content-Encoding")
+						}
+						if grw.wroteHeader {
+							rw.WriteHeader(grw.code)
+						}
+						// We have to reset response to it's pristine state when
+						// nothing is written to body or error is returned.
+						// See issue echo#424, echo#407.
+						e.Response = rw
+						w.Reset(io.Discard)
+					} else if !grw.minLengthExceeded {
+						// Write uncompressed response
+						e.Response = rw
+						if grw.wroteHeader {
+							rw.WriteHeader(grw.code)
+						}
+						grw.buffer.WriteTo(rw)
+						w.Reset(io.Discard)
+					}
+					w.Close()
+					bpool.Put(buf)
+					pool.Put(w)
+				}()
+				e.Response = grw
+			}
+
+			return e.Next()
+		},
+	}
+}
+
+type gzipResponseWriter struct {
+	http.ResponseWriter
+	io.Writer
+	buffer            *bytes.Buffer
+	minLength         int
+	code              int
+	wroteHeader       bool
+	wroteBody         bool
+	minLengthExceeded bool
+}
+
+func (w *gzipResponseWriter) WriteHeader(code int) {
+	w.Header().Del("Content-Length") // Issue echo#444
+
+	w.wroteHeader = true
+
+	// Delay writing of the header until we know if we'll actually compress the response
+	w.code = code
+}
+
+func (w *gzipResponseWriter) Write(b []byte) (int, error) {
+	if w.Header().Get("Content-Type") == "" {
+		w.Header().Set("Content-Type", http.DetectContentType(b))
+	}
+
+	w.wroteBody = true
+
+	if !w.minLengthExceeded {
+		n, err := w.buffer.Write(b)
+
+		if w.buffer.Len() >= w.minLength {
+			w.minLengthExceeded = true
+
+			// The minimum length is exceeded, add Content-Encoding header and write the header
+			w.Header().Set("Content-Encoding", gzipScheme)
+			if w.wroteHeader {
+				w.ResponseWriter.WriteHeader(w.code)
+			}
+
+			return w.Writer.Write(w.buffer.Bytes())
+		}
+
+		return n, err
+	}
+
+	return w.Writer.Write(b)
+}
+
+func (w *gzipResponseWriter) Flush() {
+	if !w.minLengthExceeded {
+		// Enforce compression because we will not know how much more data will come
+		w.minLengthExceeded = true
+		w.Header().Set("Content-Encoding", gzipScheme)
+		if w.wroteHeader {
+			w.ResponseWriter.WriteHeader(w.code)
+		}
+
+		_, _ = w.Writer.Write(w.buffer.Bytes())
+	}
+
+	_ = w.Writer.(*gzip.Writer).Flush()
+
+	_ = http.NewResponseController(w.ResponseWriter).Flush()
+}
+
+func (w *gzipResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return http.NewResponseController(w.ResponseWriter).Hijack()
+}
+
+func (w *gzipResponseWriter) Push(target string, opts *http.PushOptions) error {
+	rw := w.ResponseWriter
+	for {
+		switch p := rw.(type) {
+		case http.Pusher:
+			return p.Push(target, opts)
+		case router.RWUnwrapper:
+			rw = p.Unwrap()
+		default:
+			return http.ErrNotSupported
+		}
+	}
+}
+
+// Note: Disable the implementation for now because in case the platform
+// supports the sendfile fast-path it won't run gzipResponseWriter.Write,
+// preventing compression on the fly.
+//
+// func (w *gzipResponseWriter) ReadFrom(r io.Reader) (n int64, err error) {
+// 	if w.wroteHeader {
+// 		w.ResponseWriter.WriteHeader(w.code)
+// 	}
+// 	rw := w.ResponseWriter
+// 	for {
+// 		switch rf := rw.(type) {
+// 		case io.ReaderFrom:
+// 			return rf.ReadFrom(r)
+// 		case router.RWUnwrapper:
+// 			rw = rf.Unwrap()
+// 		default:
+// 			return io.Copy(w.ResponseWriter, r)
+// 		}
+// 	}
+// }
+
+func (w *gzipResponseWriter) Unwrap() http.ResponseWriter {
+	return w.ResponseWriter
+}