a35a5b225c
* Add ETag header. * Comply with RFC 7232. * Moved logic into httpcache.go * Changed name. * Lint * Implemented If-None-Match list. * Fixed missing header on * * Removed weak etag support. * Removed * support. * Added unit test. * Lint Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com> Co-authored-by: techknowlogick <techknowlogick@gitea.io>
83 lines
2.4 KiB
Go
83 lines
2.4 KiB
Go
// Copyright 2020 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 httpcache
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import (
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"encoding/base64"
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"fmt"
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"net/http"
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"os"
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"strconv"
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"strings"
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"time"
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"code.gitea.io/gitea/modules/setting"
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)
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// GetCacheControl returns a suitable "Cache-Control" header value
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func GetCacheControl() string {
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if !setting.IsProd() {
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return "no-store"
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}
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return "private, max-age=" + strconv.FormatInt(int64(setting.StaticCacheTime.Seconds()), 10)
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}
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// generateETag generates an ETag based on size, filename and file modification time
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func generateETag(fi os.FileInfo) string {
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etag := fmt.Sprint(fi.Size()) + fi.Name() + fi.ModTime().UTC().Format(http.TimeFormat)
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return `"` + base64.StdEncoding.EncodeToString([]byte(etag)) + `"`
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}
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// HandleTimeCache handles time-based caching for a HTTP request
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func HandleTimeCache(req *http.Request, w http.ResponseWriter, fi os.FileInfo) (handled bool) {
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w.Header().Set("Cache-Control", GetCacheControl())
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ifModifiedSince := req.Header.Get("If-Modified-Since")
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if ifModifiedSince != "" {
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t, err := time.Parse(http.TimeFormat, ifModifiedSince)
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if err == nil && fi.ModTime().Unix() <= t.Unix() {
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w.WriteHeader(http.StatusNotModified)
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return true
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}
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}
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w.Header().Set("Last-Modified", fi.ModTime().Format(http.TimeFormat))
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return false
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}
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// HandleFileETagCache handles ETag-based caching for a HTTP request
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func HandleFileETagCache(req *http.Request, w http.ResponseWriter, fi os.FileInfo) (handled bool) {
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etag := generateETag(fi)
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return HandleGenericETagCache(req, w, etag)
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}
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// HandleGenericETagCache handles ETag-based caching for a HTTP request.
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// It returns true if the request was handled.
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func HandleGenericETagCache(req *http.Request, w http.ResponseWriter, etag string) (handled bool) {
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if len(etag) > 0 {
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w.Header().Set("Etag", etag)
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if checkIfNoneMatchIsValid(req, etag) {
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w.WriteHeader(http.StatusNotModified)
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return true
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}
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}
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w.Header().Set("Cache-Control", GetCacheControl())
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return false
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}
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// checkIfNoneMatchIsValid tests if the header If-None-Match matches the ETag
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func checkIfNoneMatchIsValid(req *http.Request, etag string) bool {
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ifNoneMatch := req.Header.Get("If-None-Match")
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if len(ifNoneMatch) > 0 {
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for _, item := range strings.Split(ifNoneMatch, ",") {
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item = strings.TrimSpace(item)
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if item == etag {
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return true
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}
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}
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}
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return false
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}
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