forgejo/modules/httpcache/httpcache.go
Earl Warren 76a3001f5b
[BRANDING] add X-Forgejo-* headers
(cherry picked from commit 0a3388f93f)
(cherry picked from commit 7eba0a440a)
(cherry picked from commit eb9646c7ef)
(cherry picked from commit f1972578f5)

Conflicts:
(cherry picked from commit 7f96222fb4)
(cherry picked from commit e3c7c9fe7b)
(cherry picked from commit 84fdead902)
(cherry picked from commit 85148e1196)
(cherry picked from commit c0086bd70d)
(cherry picked from commit d1e31ef318)
(cherry picked from commit 681d3ed5c4)
2023-05-10 10:06:15 +02:00

132 lines
4.2 KiB
Go

// Copyright 2020 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package httpcache
import (
"encoding/base64"
"fmt"
"net/http"
"os"
"strconv"
"strings"
"time"
"code.gitea.io/gitea/modules/setting"
)
// SetCacheControlInHeader sets suitable cache-control headers in the response
func SetCacheControlInHeader(h http.Header, maxAge time.Duration, additionalDirectives ...string) {
directives := make([]string, 0, 2+len(additionalDirectives))
// "max-age=0 + must-revalidate" (aka "no-cache") is preferred instead of "no-store"
// because browsers may restore some input fields after navigate-back / reload a page.
if setting.IsProd {
if maxAge == 0 {
directives = append(directives, "max-age=0", "private", "must-revalidate")
} else {
directives = append(directives, "private", "max-age="+strconv.Itoa(int(maxAge.Seconds())))
}
} else {
directives = append(directives, "max-age=0", "private", "must-revalidate")
// to remind users they are using non-prod setting.
h.Set("X-Gitea-Debug", "RUN_MODE="+setting.RunMode)
h.Set("X-Forgejo-Debug", "RUN_MODE="+setting.RunMode)
}
h.Set("Cache-Control", strings.Join(append(directives, additionalDirectives...), ", "))
}
// generateETag generates an ETag based on size, filename and file modification time
func generateETag(fi os.FileInfo) string {
etag := fmt.Sprint(fi.Size()) + fi.Name() + fi.ModTime().UTC().Format(http.TimeFormat)
return `"` + base64.StdEncoding.EncodeToString([]byte(etag)) + `"`
}
// HandleTimeCache handles time-based caching for a HTTP request
func HandleTimeCache(req *http.Request, w http.ResponseWriter, fi os.FileInfo) (handled bool) {
return HandleGenericTimeCache(req, w, fi.ModTime())
}
// HandleGenericTimeCache handles time-based caching for a HTTP request
func HandleGenericTimeCache(req *http.Request, w http.ResponseWriter, lastModified time.Time) (handled bool) {
SetCacheControlInHeader(w.Header(), setting.StaticCacheTime)
ifModifiedSince := req.Header.Get("If-Modified-Since")
if ifModifiedSince != "" {
t, err := time.Parse(http.TimeFormat, ifModifiedSince)
if err == nil && lastModified.Unix() <= t.Unix() {
w.WriteHeader(http.StatusNotModified)
return true
}
}
w.Header().Set("Last-Modified", lastModified.Format(http.TimeFormat))
return false
}
// HandleFileETagCache handles ETag-based caching for a HTTP request
func HandleFileETagCache(req *http.Request, w http.ResponseWriter, fi os.FileInfo) (handled bool) {
etag := generateETag(fi)
return HandleGenericETagCache(req, w, etag)
}
// HandleGenericETagCache handles ETag-based caching for a HTTP request.
// It returns true if the request was handled.
func HandleGenericETagCache(req *http.Request, w http.ResponseWriter, etag string) (handled bool) {
if len(etag) > 0 {
w.Header().Set("Etag", etag)
if checkIfNoneMatchIsValid(req, etag) {
w.WriteHeader(http.StatusNotModified)
return true
}
}
SetCacheControlInHeader(w.Header(), setting.StaticCacheTime)
return false
}
// checkIfNoneMatchIsValid tests if the header If-None-Match matches the ETag
func checkIfNoneMatchIsValid(req *http.Request, etag string) bool {
ifNoneMatch := req.Header.Get("If-None-Match")
if len(ifNoneMatch) > 0 {
for _, item := range strings.Split(ifNoneMatch, ",") {
item = strings.TrimSpace(item)
if item == etag {
return true
}
}
}
return false
}
// HandleGenericETagTimeCache handles ETag-based caching with Last-Modified caching for a HTTP request.
// It returns true if the request was handled.
func HandleGenericETagTimeCache(req *http.Request, w http.ResponseWriter, etag string, lastModified time.Time) (handled bool) {
if len(etag) > 0 {
w.Header().Set("Etag", etag)
}
if !lastModified.IsZero() {
w.Header().Set("Last-Modified", lastModified.Format(http.TimeFormat))
}
if len(etag) > 0 {
if checkIfNoneMatchIsValid(req, etag) {
w.WriteHeader(http.StatusNotModified)
return true
}
}
if !lastModified.IsZero() {
ifModifiedSince := req.Header.Get("If-Modified-Since")
if ifModifiedSince != "" {
t, err := time.Parse(http.TimeFormat, ifModifiedSince)
if err == nil && lastModified.Unix() <= t.Unix() {
w.WriteHeader(http.StatusNotModified)
return true
}
}
}
SetCacheControlInHeader(w.Header(), setting.StaticCacheTime)
return false
}