Retro68/gcc/libgo/go/net/http/fs.go
Wolfgang Thaller aaf905ce07 add gcc 4.70
2012-03-28 01:13:14 +02:00

368 lines
9.7 KiB
Go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// HTTP file system request handler
package http
import (
"errors"
"fmt"
"io"
"mime"
"os"
"path"
"path/filepath"
"strconv"
"strings"
"time"
)
// A Dir implements http.FileSystem using the native file
// system restricted to a specific directory tree.
//
// An empty Dir is treated as ".".
type Dir string
func (d Dir) Open(name string) (File, error) {
if filepath.Separator != '/' && strings.IndexRune(name, filepath.Separator) >= 0 {
return nil, errors.New("http: invalid character in file path")
}
dir := string(d)
if dir == "" {
dir = "."
}
f, err := os.Open(filepath.Join(dir, filepath.FromSlash(path.Clean("/"+name))))
if err != nil {
return nil, err
}
return f, nil
}
// A FileSystem implements access to a collection of named files.
// The elements in a file path are separated by slash ('/', U+002F)
// characters, regardless of host operating system convention.
type FileSystem interface {
Open(name string) (File, error)
}
// A File is returned by a FileSystem's Open method and can be
// served by the FileServer implementation.
type File interface {
Close() error
Stat() (os.FileInfo, error)
Readdir(count int) ([]os.FileInfo, error)
Read([]byte) (int, error)
Seek(offset int64, whence int) (int64, error)
}
func dirList(w ResponseWriter, f File) {
w.Header().Set("Content-Type", "text/html; charset=utf-8")
fmt.Fprintf(w, "<pre>\n")
for {
dirs, err := f.Readdir(100)
if err != nil || len(dirs) == 0 {
break
}
for _, d := range dirs {
name := d.Name()
if d.IsDir() {
name += "/"
}
// TODO htmlescape
fmt.Fprintf(w, "<a href=\"%s\">%s</a>\n", name, name)
}
}
fmt.Fprintf(w, "</pre>\n")
}
// ServeContent replies to the request using the content in the
// provided ReadSeeker. The main benefit of ServeContent over io.Copy
// is that it handles Range requests properly, sets the MIME type, and
// handles If-Modified-Since requests.
//
// If the response's Content-Type header is not set, ServeContent
// first tries to deduce the type from name's file extension and,
// if that fails, falls back to reading the first block of the content
// and passing it to DetectContentType.
// The name is otherwise unused; in particular it can be empty and is
// never sent in the response.
//
// If modtime is not the zero time, ServeContent includes it in a
// Last-Modified header in the response. If the request includes an
// If-Modified-Since header, ServeContent uses modtime to decide
// whether the content needs to be sent at all.
//
// The content's Seek method must work: ServeContent uses
// a seek to the end of the content to determine its size.
//
// Note that *os.File implements the io.ReadSeeker interface.
func ServeContent(w ResponseWriter, req *Request, name string, modtime time.Time, content io.ReadSeeker) {
size, err := content.Seek(0, os.SEEK_END)
if err != nil {
Error(w, "seeker can't seek", StatusInternalServerError)
return
}
_, err = content.Seek(0, os.SEEK_SET)
if err != nil {
Error(w, "seeker can't seek", StatusInternalServerError)
return
}
serveContent(w, req, name, modtime, size, content)
}
// if name is empty, filename is unknown. (used for mime type, before sniffing)
// if modtime.IsZero(), modtime is unknown.
// content must be seeked to the beginning of the file.
func serveContent(w ResponseWriter, r *Request, name string, modtime time.Time, size int64, content io.ReadSeeker) {
if checkLastModified(w, r, modtime) {
return
}
code := StatusOK
// If Content-Type isn't set, use the file's extension to find it.
if w.Header().Get("Content-Type") == "" {
ctype := mime.TypeByExtension(filepath.Ext(name))
if ctype == "" {
// read a chunk to decide between utf-8 text and binary
var buf [1024]byte
n, _ := io.ReadFull(content, buf[:])
b := buf[:n]
ctype = DetectContentType(b)
_, err := content.Seek(0, os.SEEK_SET) // rewind to output whole file
if err != nil {
Error(w, "seeker can't seek", StatusInternalServerError)
return
}
}
w.Header().Set("Content-Type", ctype)
}
// handle Content-Range header.
// TODO(adg): handle multiple ranges
sendSize := size
if size >= 0 {
ranges, err := parseRange(r.Header.Get("Range"), size)
if err == nil && len(ranges) > 1 {
err = errors.New("multiple ranges not supported")
}
if err != nil {
Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
return
}
if len(ranges) == 1 {
ra := ranges[0]
if _, err := content.Seek(ra.start, os.SEEK_SET); err != nil {
Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
return
}
sendSize = ra.length
code = StatusPartialContent
w.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", ra.start, ra.start+ra.length-1, size))
}
w.Header().Set("Accept-Ranges", "bytes")
if w.Header().Get("Content-Encoding") == "" {
w.Header().Set("Content-Length", strconv.FormatInt(sendSize, 10))
}
}
w.WriteHeader(code)
if r.Method != "HEAD" {
if sendSize == -1 {
io.Copy(w, content)
} else {
io.CopyN(w, content, sendSize)
}
}
}
// modtime is the modification time of the resource to be served, or IsZero().
// return value is whether this request is now complete.
func checkLastModified(w ResponseWriter, r *Request, modtime time.Time) bool {
if modtime.IsZero() {
return false
}
// The Date-Modified header truncates sub-second precision, so
// use mtime < t+1s instead of mtime <= t to check for unmodified.
if t, err := time.Parse(TimeFormat, r.Header.Get("If-Modified-Since")); err == nil && modtime.Before(t.Add(1*time.Second)) {
w.WriteHeader(StatusNotModified)
return true
}
w.Header().Set("Last-Modified", modtime.UTC().Format(TimeFormat))
return false
}
// name is '/'-separated, not filepath.Separator.
func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirect bool) {
const indexPage = "/index.html"
// redirect .../index.html to .../
// can't use Redirect() because that would make the path absolute,
// which would be a problem running under StripPrefix
if strings.HasSuffix(r.URL.Path, indexPage) {
localRedirect(w, r, "./")
return
}
f, err := fs.Open(name)
if err != nil {
// TODO expose actual error?
NotFound(w, r)
return
}
defer f.Close()
d, err1 := f.Stat()
if err1 != nil {
// TODO expose actual error?
NotFound(w, r)
return
}
if redirect {
// redirect to canonical path: / at end of directory url
// r.URL.Path always begins with /
url := r.URL.Path
if d.IsDir() {
if url[len(url)-1] != '/' {
localRedirect(w, r, path.Base(url)+"/")
return
}
} else {
if url[len(url)-1] == '/' {
localRedirect(w, r, "../"+path.Base(url))
return
}
}
}
// use contents of index.html for directory, if present
if d.IsDir() {
if checkLastModified(w, r, d.ModTime()) {
return
}
index := name + indexPage
ff, err := fs.Open(index)
if err == nil {
defer ff.Close()
dd, err := ff.Stat()
if err == nil {
name = index
d = dd
f = ff
}
}
}
if d.IsDir() {
dirList(w, f)
return
}
serveContent(w, r, d.Name(), d.ModTime(), d.Size(), f)
}
// localRedirect gives a Moved Permanently response.
// It does not convert relative paths to absolute paths like Redirect does.
func localRedirect(w ResponseWriter, r *Request, newPath string) {
if q := r.URL.RawQuery; q != "" {
newPath += "?" + q
}
w.Header().Set("Location", newPath)
w.WriteHeader(StatusMovedPermanently)
}
// ServeFile replies to the request with the contents of the named file or directory.
func ServeFile(w ResponseWriter, r *Request, name string) {
dir, file := filepath.Split(name)
serveFile(w, r, Dir(dir), file, false)
}
type fileHandler struct {
root FileSystem
}
// FileServer returns a handler that serves HTTP requests
// with the contents of the file system rooted at root.
//
// To use the operating system's file system implementation,
// use http.Dir:
//
// http.Handle("/", http.FileServer(http.Dir("/tmp")))
func FileServer(root FileSystem) Handler {
return &fileHandler{root}
}
func (f *fileHandler) ServeHTTP(w ResponseWriter, r *Request) {
upath := r.URL.Path
if !strings.HasPrefix(upath, "/") {
upath = "/" + upath
r.URL.Path = upath
}
serveFile(w, r, f.root, path.Clean(upath), true)
}
// httpRange specifies the byte range to be sent to the client.
type httpRange struct {
start, length int64
}
// parseRange parses a Range header string as per RFC 2616.
func parseRange(s string, size int64) ([]httpRange, error) {
if s == "" {
return nil, nil // header not present
}
const b = "bytes="
if !strings.HasPrefix(s, b) {
return nil, errors.New("invalid range")
}
var ranges []httpRange
for _, ra := range strings.Split(s[len(b):], ",") {
i := strings.Index(ra, "-")
if i < 0 {
return nil, errors.New("invalid range")
}
start, end := ra[:i], ra[i+1:]
var r httpRange
if start == "" {
// If no start is specified, end specifies the
// range start relative to the end of the file.
i, err := strconv.ParseInt(end, 10, 64)
if err != nil {
return nil, errors.New("invalid range")
}
if i > size {
i = size
}
r.start = size - i
r.length = size - r.start
} else {
i, err := strconv.ParseInt(start, 10, 64)
if err != nil || i > size || i < 0 {
return nil, errors.New("invalid range")
}
r.start = i
if end == "" {
// If no end is specified, range extends to end of the file.
r.length = size - r.start
} else {
i, err := strconv.ParseInt(end, 10, 64)
if err != nil || r.start > i {
return nil, errors.New("invalid range")
}
if i >= size {
i = size - 1
}
r.length = i - r.start + 1
}
}
ranges = append(ranges, r)
}
return ranges, nil
}