1 files changed, 265 insertions, 0 deletions
diff --git a/libgo/go/http/fs.go b/libgo/go/http/fs.go
new file mode 100644
index 000000000..bbfa58d26
--- /dev/null
+++ b/libgo/go/http/fs.go
@@ -0,0 +1,265 @@
+// 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 (
+	"fmt"
+	"io"
+	"mime"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+	"time"
+	"utf8"
+)
+
+// Heuristic: b is text if it is valid UTF-8 and doesn't
+// contain any unprintable ASCII or Unicode characters.
+func isText(b []byte) bool {
+	for len(b) > 0 && utf8.FullRune(b) {
+		rune, size := utf8.DecodeRune(b)
+		if size == 1 && rune == utf8.RuneError {
+			// decoding error
+			return false
+		}
+		if 0x7F <= rune && rune <= 0x9F {
+			return false
+		}
+		if rune < ' ' {
+			switch rune {
+			case '\n', '\r', '\t':
+				// okay
+			default:
+				// binary garbage
+				return false
+			}
+		}
+		b = b[size:]
+	}
+	return true
+}
+
+func dirList(w ResponseWriter, f *os.File) {
+	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.IsDirectory() {
+				name += "/"
+			}
+			// TODO htmlescape
+			fmt.Fprintf(w, "<a href=\"%s\">%s</a>\n", name, name)
+		}
+	}
+	fmt.Fprintf(w, "</pre>\n")
+}
+
+func serveFile(w ResponseWriter, r *Request, name string, redirect bool) {
+	const indexPage = "/index.html"
+
+	// redirect .../index.html to .../
+	if strings.HasSuffix(r.URL.Path, indexPage) {
+		Redirect(w, r, r.URL.Path[0:len(r.URL.Path)-len(indexPage)+1], StatusMovedPermanently)
+		return
+	}
+
+	f, err := os.Open(name, os.O_RDONLY, 0)
+	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.IsDirectory() {
+			if url[len(url)-1] != '/' {
+				Redirect(w, r, url+"/", StatusMovedPermanently)
+				return
+			}
+		} else {
+			if url[len(url)-1] == '/' {
+				Redirect(w, r, url[0:len(url)-1], StatusMovedPermanently)
+				return
+			}
+		}
+	}
+
+	if t, _ := time.Parse(TimeFormat, r.Header["If-Modified-Since"]); t != nil && d.Mtime_ns/1e9 <= t.Seconds() {
+		w.WriteHeader(StatusNotModified)
+		return
+	}
+	w.SetHeader("Last-Modified", time.SecondsToUTC(d.Mtime_ns/1e9).Format(TimeFormat))
+
+	// use contents of index.html for directory, if present
+	if d.IsDirectory() {
+		index := name + indexPage
+		ff, err := os.Open(index, os.O_RDONLY, 0)
+		if err == nil {
+			defer ff.Close()
+			dd, err := ff.Stat()
+			if err == nil {
+				name = index
+				d = dd
+				f = ff
+			}
+		}
+	}
+
+	if d.IsDirectory() {
+		dirList(w, f)
+		return
+	}
+
+	// serve file
+	size := d.Size
+	code := StatusOK
+
+	// use extension to find content type.
+	ext := path.Ext(name)
+	if ctype := mime.TypeByExtension(ext); ctype != "" {
+		w.SetHeader("Content-Type", ctype)
+	} else {
+		// read first chunk to decide between utf-8 text and binary
+		var buf [1024]byte
+		n, _ := io.ReadFull(f, buf[:])
+		b := buf[:n]
+		if isText(b) {
+			w.SetHeader("Content-Type", "text-plain; charset=utf-8")
+		} else {
+			w.SetHeader("Content-Type", "application/octet-stream") // generic binary
+		}
+		f.Seek(0, 0) // rewind to output whole file
+	}
+
+	// handle Content-Range header.
+	// TODO(adg): handle multiple ranges
+	ranges, err := parseRange(r.Header["Range"], size)
+	if err != nil || len(ranges) > 1 {
+		Error(w, err.String(), StatusRequestedRangeNotSatisfiable)
+		return
+	}
+	if len(ranges) == 1 {
+		ra := ranges[0]
+		if _, err := f.Seek(ra.start, 0); err != nil {
+			Error(w, err.String(), StatusRequestedRangeNotSatisfiable)
+			return
+		}
+		size = ra.length
+		code = StatusPartialContent
+		w.SetHeader("Content-Range", fmt.Sprintf("bytes %d-%d/%d", ra.start, ra.start+ra.length-1, d.Size))
+	}
+
+	w.SetHeader("Accept-Ranges", "bytes")
+	w.SetHeader("Content-Length", strconv.Itoa64(size))
+
+	w.WriteHeader(code)
+
+	if r.Method != "HEAD" {
+		io.Copyn(w, f, size)
+	}
+}
+
+// ServeFile replies to the request with the contents of the named file or directory.
+func ServeFile(w ResponseWriter, r *Request, name string) {
+	serveFile(w, r, name, false)
+}
+
+type fileHandler struct {
+	root   string
+	prefix string
+}
+
+// FileServer returns a handler that serves HTTP requests
+// with the contents of the file system rooted at root.
+// It strips prefix from the incoming requests before
+// looking up the file name in the file system.
+func FileServer(root, prefix string) Handler { return &fileHandler{root, prefix} }
+
+func (f *fileHandler) ServeHTTP(w ResponseWriter, r *Request) {
+	path := r.URL.Path
+	if !strings.HasPrefix(path, f.prefix) {
+		NotFound(w, r)
+		return
+	}
+	path = path[len(f.prefix):]
+	serveFile(w, r, f.root+"/"+path, 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, os.Error) {
+	if s == "" {
+		return nil, nil // header not present
+	}
+	const b = "bytes="
+	if !strings.HasPrefix(s, b) {
+		return nil, os.NewError("invalid range")
+	}
+	var ranges []httpRange
+	for _, ra := range strings.Split(s[len(b):], ",", -1) {
+		i := strings.Index(ra, "-")
+		if i < 0 {
+			return nil, os.NewError("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.Atoi64(end)
+			if err != nil {
+				return nil, os.NewError("invalid range")
+			}
+			if i > size {
+				i = size
+			}
+			r.start = size - i
+			r.length = size - r.start
+		} else {
+			i, err := strconv.Atoi64(start)
+			if err != nil || i > size || i < 0 {
+				return nil, os.NewError("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.Atoi64(end)
+				if err != nil || r.start > i {
+					return nil, os.NewError("invalid range")
+				}
+				if i >= size {
+					i = size - 1
+				}
+				r.length = i - r.start + 1
+			}
+		}
+		ranges = append(ranges, r)
+	}
+	return ranges, nil
+}