mirror of
https://github.com/gravitational/teleport.git
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83 lines
2.6 KiB
Go
83 lines
2.6 KiB
Go
/*
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* Teleport
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* Copyright (C) 2023 Gravitational, Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package web
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import (
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"compress/gzip"
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"io"
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"net/http"
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"strings"
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"sync"
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)
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// writerPool is a sync.Pool for shared gzip writers.
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// each gzip writer allocates a lot of memory
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// so it makes sense to reset the writer and reuse the
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// internal buffers to avoid too many objects on the heap
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var writerPool = sync.Pool{
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New: func() interface{} {
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gz := gzip.NewWriter(io.Discard)
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return gz
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},
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}
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func newGzipResponseWriter(w http.ResponseWriter) gzipResponseWriter {
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gz := writerPool.Get().(*gzip.Writer)
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gz.Reset(w)
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return gzipResponseWriter{gz: gz, ResponseWriter: w}
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}
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type gzipResponseWriter struct {
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gz *gzip.Writer
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http.ResponseWriter
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}
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// Write uses the Writer part of gzipResponseWriter to write the output.
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func (w gzipResponseWriter) Write(b []byte) (int, error) {
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_, haveType := w.Header()["Content-Type"]
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// Explicitly set Content-Type if it has not been set previously
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if !haveType {
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// If no content type, apply sniffing algorithm to un-gzipped body.
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w.Header().Set("Content-Type", http.DetectContentType(b))
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}
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return w.gz.Write(b)
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}
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// makeGzipHandler adds support for gzip compression for given handler.
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func makeGzipHandler(handler http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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// Check if the client can accept the gzip encoding and that this is not an image asset.
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if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") || isCompressedImageRequest(r) {
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handler.ServeHTTP(w, r)
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return
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}
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// Set the HTTP header indicating encoding.
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w.Header().Set("Content-Encoding", "gzip")
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gzw := newGzipResponseWriter(w)
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defer gzw.gz.Close()
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handler.ServeHTTP(gzw, r)
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})
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}
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// isCompressedImageRequest checks whether a request is for a png or jpg/jpeg
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func isCompressedImageRequest(r *http.Request) bool {
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return strings.HasSuffix(r.URL.Path, ".png") || strings.HasSuffix(r.URL.Path, ".jpg") || strings.HasSuffix(r.URL.Path, ".jpeg")
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}
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