mirror of
https://github.com/go-gitea/gitea.git
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326 lines
8.5 KiB
Go
326 lines
8.5 KiB
Go
// Copyright 2019 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package gzip
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import (
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"bufio"
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"fmt"
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"io"
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"net"
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"net/http"
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"regexp"
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"strconv"
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"strings"
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"sync"
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"github.com/klauspost/compress/gzip"
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"gopkg.in/macaron.v1"
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)
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const (
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acceptEncodingHeader = "Accept-Encoding"
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contentEncodingHeader = "Content-Encoding"
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contentLengthHeader = "Content-Length"
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contentTypeHeader = "Content-Type"
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rangeHeader = "Range"
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varyHeader = "Vary"
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)
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const (
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// MinSize is the minimum size of content we will compress
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MinSize = 1400
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)
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// noopClosers are io.Writers with a shim to prevent early closure
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type noopCloser struct {
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io.Writer
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}
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func (noopCloser) Close() error { return nil }
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// WriterPool is a gzip writer pool to reduce workload on creation of
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// gzip writers
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type WriterPool struct {
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pool sync.Pool
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compressionLevel int
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}
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// NewWriterPool creates a new pool
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func NewWriterPool(compressionLevel int) *WriterPool {
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return &WriterPool{pool: sync.Pool{
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// New will return nil, we'll manage the creation of new
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// writers in the middleware
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New: func() interface{} { return nil },
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},
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compressionLevel: compressionLevel}
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}
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// Get a writer from the pool - or create one if not available
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func (wp *WriterPool) Get(rw macaron.ResponseWriter) *gzip.Writer {
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ret := wp.pool.Get()
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if ret == nil {
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ret, _ = gzip.NewWriterLevel(rw, wp.compressionLevel)
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} else {
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ret.(*gzip.Writer).Reset(rw)
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}
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return ret.(*gzip.Writer)
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}
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// Put returns a writer to the pool
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func (wp *WriterPool) Put(w *gzip.Writer) {
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wp.pool.Put(w)
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}
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var writerPool WriterPool
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// Options represents the configuration for the gzip middleware
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type Options struct {
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CompressionLevel int
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}
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func validateCompressionLevel(level int) bool {
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return level == gzip.DefaultCompression ||
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level == gzip.ConstantCompression ||
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(level >= gzip.BestSpeed && level <= gzip.BestCompression)
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}
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func validate(options []Options) Options {
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// Default to level 4 compression (Best results seem to be between 4 and 6)
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opt := Options{CompressionLevel: 4}
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if len(options) > 0 {
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opt = options[0]
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}
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if !validateCompressionLevel(opt.CompressionLevel) {
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opt.CompressionLevel = 4
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}
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return opt
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}
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// Middleware creates a macaron.Handler to proxy the response
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func Middleware(options ...Options) macaron.Handler {
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opt := validate(options)
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writerPool = *NewWriterPool(opt.CompressionLevel)
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regex := regexp.MustCompile(`bytes=(\d+)\-.*`)
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return func(ctx *macaron.Context) {
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// If the client won't accept gzip or x-gzip don't compress
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if !strings.Contains(ctx.Req.Header.Get(acceptEncodingHeader), "gzip") &&
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!strings.Contains(ctx.Req.Header.Get(acceptEncodingHeader), "x-gzip") {
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return
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}
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// If the client is asking for a specific range of bytes - don't compress
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if rangeHdr := ctx.Req.Header.Get(rangeHeader); rangeHdr != "" {
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match := regex.FindStringSubmatch(rangeHdr)
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if len(match) > 1 {
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return
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}
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}
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// OK we should proxy the response writer
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// We are still not necessarily going to compress...
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proxyWriter := &ProxyResponseWriter{
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ResponseWriter: ctx.Resp,
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}
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defer proxyWriter.Close()
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ctx.Resp = proxyWriter
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ctx.MapTo(proxyWriter, (*http.ResponseWriter)(nil))
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// Check if render middleware has been registered,
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// if yes, we need to modify ResponseWriter for it as well.
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if _, ok := ctx.Render.(*macaron.DummyRender); !ok {
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ctx.Render.SetResponseWriter(proxyWriter)
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}
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ctx.Next()
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}
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}
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// ProxyResponseWriter is a wrapped macaron ResponseWriter that may compress its contents
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type ProxyResponseWriter struct {
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writer io.WriteCloser
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macaron.ResponseWriter
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stopped bool
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code int
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buf []byte
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}
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// Write appends data to the proxied gzip writer.
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func (proxy *ProxyResponseWriter) Write(b []byte) (int, error) {
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// if writer is initialized, use the writer
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if proxy.writer != nil {
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return proxy.writer.Write(b)
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}
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proxy.buf = append(proxy.buf, b...)
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var (
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contentLength, _ = strconv.Atoi(proxy.Header().Get(contentLengthHeader))
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contentType = proxy.Header().Get(contentTypeHeader)
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contentEncoding = proxy.Header().Get(contentEncodingHeader)
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)
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// OK if an encoding hasn't been chosen, and content length > 1400
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// and content type isn't a compressed type
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if contentEncoding == "" &&
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(contentLength == 0 || contentLength >= MinSize) &&
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(contentType == "" || !compressedContentType(contentType)) {
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// If current buffer is less than the min size and a Content-Length isn't set, then wait
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if len(proxy.buf) < MinSize && contentLength == 0 {
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return len(b), nil
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}
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// If the Content-Length is larger than minSize or the current buffer is larger than minSize, then continue.
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if contentLength >= MinSize || len(proxy.buf) >= MinSize {
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// if we don't know the content type, infer it
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if contentType == "" {
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contentType = http.DetectContentType(proxy.buf)
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proxy.Header().Set(contentTypeHeader, contentType)
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}
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// If the Content-Type is not compressed - Compress!
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if !compressedContentType(contentType) {
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if err := proxy.startGzip(); err != nil {
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return 0, err
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}
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return len(b), nil
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}
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}
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}
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// If we got here, we should not GZIP this response.
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if err := proxy.startPlain(); err != nil {
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return 0, err
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}
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return len(b), nil
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}
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func (proxy *ProxyResponseWriter) startGzip() error {
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// Set the content-encoding and vary headers.
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proxy.Header().Set(contentEncodingHeader, "gzip")
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proxy.Header().Set(varyHeader, acceptEncodingHeader)
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// if the Content-Length is already set, then calls to Write on gzip
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// will fail to set the Content-Length header since its already set
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// See: https://github.com/golang/go/issues/14975.
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proxy.Header().Del(contentLengthHeader)
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// Write the header to gzip response.
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if proxy.code != 0 {
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proxy.ResponseWriter.WriteHeader(proxy.code)
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// Ensure that no other WriteHeader's happen
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proxy.code = 0
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}
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// Initialize and flush the buffer into the gzip response if there are any bytes.
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// If there aren't any, we shouldn't initialize it yet because on Close it will
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// write the gzip header even if nothing was ever written.
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if len(proxy.buf) > 0 {
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// Initialize the GZIP response.
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proxy.writer = writerPool.Get(proxy.ResponseWriter)
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return proxy.writeBuf()
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}
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return nil
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}
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func (proxy *ProxyResponseWriter) startPlain() error {
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if proxy.code != 0 {
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proxy.ResponseWriter.WriteHeader(proxy.code)
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proxy.code = 0
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}
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proxy.stopped = true
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proxy.writer = noopCloser{proxy.ResponseWriter}
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return proxy.writeBuf()
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}
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func (proxy *ProxyResponseWriter) writeBuf() error {
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if proxy.buf == nil {
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return nil
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}
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n, err := proxy.writer.Write(proxy.buf)
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// This should never happen (per io.Writer docs), but if the write didn't
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// accept the entire buffer but returned no specific error, we have no clue
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// what's going on, so abort just to be safe.
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if err == nil && n < len(proxy.buf) {
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err = io.ErrShortWrite
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}
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proxy.buf = nil
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return err
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}
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// WriteHeader will ensure that we have setup the writer before we write the header
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func (proxy *ProxyResponseWriter) WriteHeader(code int) {
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if proxy.code == 0 {
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proxy.code = code
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}
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}
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// Close the writer
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func (proxy *ProxyResponseWriter) Close() error {
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if proxy.stopped {
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return nil
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}
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if proxy.writer == nil {
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err := proxy.startPlain()
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if err != nil {
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return fmt.Errorf("GzipMiddleware: write to regular responseWriter at close gets error: %q", err.Error())
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}
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}
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err := proxy.writer.Close()
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if poolWriter, ok := proxy.writer.(*gzip.Writer); ok {
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writerPool.Put(poolWriter)
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}
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proxy.writer = nil
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proxy.stopped = true
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return err
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}
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// Flush the writer
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func (proxy *ProxyResponseWriter) Flush() {
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if proxy.writer == nil {
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return
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}
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if gw, ok := proxy.writer.(*gzip.Writer); ok {
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gw.Flush()
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}
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proxy.ResponseWriter.Flush()
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}
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// Hijack implements http.Hijacker. If the underlying ResponseWriter is a
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// Hijacker, its Hijack method is returned. Otherwise an error is returned.
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func (proxy *ProxyResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
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hijacker, ok := proxy.ResponseWriter.(http.Hijacker)
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if !ok {
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return nil, nil, fmt.Errorf("the ResponseWriter doesn't support the Hijacker interface")
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}
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return hijacker.Hijack()
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}
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// verify Hijacker interface implementation
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var _ http.Hijacker = &ProxyResponseWriter{}
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func compressedContentType(contentType string) bool {
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switch contentType {
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case "application/zip":
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return true
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case "application/x-gzip":
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return true
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case "application/gzip":
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return true
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default:
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return false
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}
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}
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