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// Copyright 2013 Martini Authors
// Copyright 2014 The Macaron Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.
package macaron
import (
"encoding/base64"
"log"
"net/http"
"path"
"path/filepath"
"strings"
"sync"
)
// StaticOptions is a struct for specifying configuration options for the macaron.Static middleware.
type StaticOptions struct {
// Prefix is the optional prefix used to serve the static directory content
Prefix string
// SkipLogging will disable [Static] log messages when a static file is served.
SkipLogging bool
// IndexFile defines which file to serve as index if it exists.
IndexFile string
// Expires defines which user-defined function to use for producing a HTTP Expires Header
// https://developers.google.com/speed/docs/insights/LeverageBrowserCaching
Expires func() string
// ETag defines if we should add an ETag header
// https://developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/http-caching#validating-cached-responses-with-etags
ETag bool
// FileSystem is the interface for supporting any implmentation of file system.
FileSystem http.FileSystem
}
// FIXME: to be deleted.
type staticMap struct {
lock sync.RWMutex
data map[string]*http.Dir
}
func (sm *staticMap) Set(dir *http.Dir) {
sm.lock.Lock()
defer sm.lock.Unlock()
sm.data[string(*dir)] = dir
}
func (sm *staticMap) Get(name string) *http.Dir {
sm.lock.RLock()
defer sm.lock.RUnlock()
return sm.data[name]
}
func (sm *staticMap) Delete(name string) {
sm.lock.Lock()
defer sm.lock.Unlock()
delete(sm.data, name)
}
var statics = staticMap{sync.RWMutex{}, map[string]*http.Dir{}}
// staticFileSystem implements http.FileSystem interface.
type staticFileSystem struct {
dir *http.Dir
}
func newStaticFileSystem(directory string) staticFileSystem {
if !filepath.IsAbs(directory) {
directory = filepath.Join(Root, directory)
}
dir := http.Dir(directory)
statics.Set(&dir)
return staticFileSystem{&dir}
}
func (fs staticFileSystem) Open(name string) (http.File, error) {
return fs.dir.Open(name)
}
func prepareStaticOption(dir string, opt StaticOptions) StaticOptions {
// Defaults
if len(opt.IndexFile) == 0 {
opt.IndexFile = "index.html"
}
// Normalize the prefix if provided
if opt.Prefix != "" {
// Ensure we have a leading '/'
if opt.Prefix[0] != '/' {
opt.Prefix = "/" + opt.Prefix
}
// Remove any trailing '/'
opt.Prefix = strings.TrimRight(opt.Prefix, "/")
}
if opt.FileSystem == nil {
opt.FileSystem = newStaticFileSystem(dir)
}
return opt
}
func prepareStaticOptions(dir string, options []StaticOptions) StaticOptions {
var opt StaticOptions
if len(options) > 0 {
opt = options[0]
}
return prepareStaticOption(dir, opt)
}
func staticHandler(ctx *Context, log *log.Logger, opt StaticOptions) bool {
if ctx.Req.Method != "GET" && ctx.Req.Method != "HEAD" {
return false
}
file := ctx.Req.URL.Path
// if we have a prefix, filter requests by stripping the prefix
if opt.Prefix != "" {
if !strings.HasPrefix(file, opt.Prefix) {
return false
}
file = file[len(opt.Prefix):]
if file != "" && file[0] != '/' {
return false
}
}
f, err := opt.FileSystem.Open(file)
if err != nil {
return false
}
defer f.Close()
fi, err := f.Stat()
if err != nil {
return true // File exists but fail to open.
}
// Try to serve index file
if fi.IsDir() {
// Redirect if missing trailing slash.
if !strings.HasSuffix(ctx.Req.URL.Path, "/") {
http.Redirect(ctx.Resp, ctx.Req.Request, ctx.Req.URL.Path+"/", http.StatusFound)
return true
}
file = path.Join(file, opt.IndexFile)
f, err = opt.FileSystem.Open(file)
if err != nil {
return false // Discard error.
}
defer f.Close()
fi, err = f.Stat()
if err != nil || fi.IsDir() {
return true
}
}
if !opt.SkipLogging {
log.Println("[Static] Serving " + file)
}
// Add an Expires header to the static content
if opt.Expires != nil {
ctx.Resp.Header().Set("Expires", opt.Expires())
}
if opt.ETag {
tag := GenerateETag(string(fi.Size()), fi.Name(), fi.ModTime().UTC().Format(http.TimeFormat))
ctx.Resp.Header().Set("ETag", tag)
}
http.ServeContent(ctx.Resp, ctx.Req.Request, file, fi.ModTime(), f)
return true
}
// GenerateETag generates an ETag based on size, filename and file modification time
func GenerateETag(fileSize, fileName, modTime string) string {
etag := fileSize + fileName + modTime
return base64.StdEncoding.EncodeToString([]byte(etag))
}
// Static returns a middleware handler that serves static files in the given directory.
func Static(directory string, staticOpt ...StaticOptions) Handler {
opt := prepareStaticOptions(directory, staticOpt)
return func(ctx *Context, log *log.Logger) {
staticHandler(ctx, log, opt)
}
}
// Statics registers multiple static middleware handlers all at once.
func Statics(opt StaticOptions, dirs ...string) Handler {
if len(dirs) == 0 {
panic("no static directory is given")
}
opts := make([]StaticOptions, len(dirs))
for i := range dirs {
opts[i] = prepareStaticOption(dirs[i], opt)
}
return func(ctx *Context, log *log.Logger) {
for i := range opts {
if staticHandler(ctx, log, opts[i]) {
return
}
}
}
}
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