http: ServeFile to handle Range header for partial requests

and send Content-Length.

Also includes some testing of the server code.

R=rsc
CC=golang-dev
https://golang.org/cl/2831041

src/pkg/http/fs_test.go

@@ -0,0 +1,172 @@
+// Copyright 2010 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.
+
+package http
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"sync"
+	"testing"
+)
+
+var ParseRangeTests = []struct {
+	s      string
+	length int64
+	r      []httpRange
+}{
+	{"", 0, nil},
+	{"foo", 0, nil},
+	{"bytes=", 0, nil},
+	{"bytes=5-4", 10, nil},
+	{"bytes=0-2,5-4", 10, nil},
+	{"bytes=0-9", 10, []httpRange{{0, 10}}},
+	{"bytes=0-", 10, []httpRange{{0, 10}}},
+	{"bytes=5-", 10, []httpRange{{5, 5}}},
+	{"bytes=0-20", 10, []httpRange{{0, 10}}},
+	{"bytes=15-,0-5", 10, nil},
+	{"bytes=-5", 10, []httpRange{{5, 5}}},
+	{"bytes=-15", 10, []httpRange{{0, 10}}},
+	{"bytes=0-499", 10000, []httpRange{{0, 500}}},
+	{"bytes=500-999", 10000, []httpRange{{500, 500}}},
+	{"bytes=-500", 10000, []httpRange{{9500, 500}}},
+	{"bytes=9500-", 10000, []httpRange{{9500, 500}}},
+	{"bytes=0-0,-1", 10000, []httpRange{{0, 1}, {9999, 1}}},
+	{"bytes=500-600,601-999", 10000, []httpRange{{500, 101}, {601, 399}}},
+	{"bytes=500-700,601-999", 10000, []httpRange{{500, 201}, {601, 399}}},
+}
+
+func TestParseRange(t *testing.T) {
+	for _, test := range ParseRangeTests {
+		r := test.r
+		ranges, err := parseRange(test.s, test.length)
+		if err != nil && r != nil {
+			t.Errorf("parseRange(%q) returned error %q", test.s, err)
+		}
+		if len(ranges) != len(r) {
+			t.Errorf("len(parseRange(%q)) = %d, want %d", test.s, len(ranges), len(r))
+			continue
+		}
+		for i := range r {
+			if ranges[i].start != r[i].start {
+				t.Errorf("parseRange(%q)[%d].start = %d, want %d", test.s, i, ranges[i].start, r[i].start)
+			}
+			if ranges[i].length != r[i].length {
+				t.Errorf("parseRange(%q)[%d].length = %d, want %d", test.s, i, ranges[i].length, r[i].length)
+			}
+		}
+	}
+}
+
+const (
+	testFile       = "testdata/file"
+	testFileLength = 11
+)
+
+var (
+	serverOnce sync.Once
+	serverAddr string
+)
+
+func startServer(t *testing.T) {
+	serverOnce.Do(func() {
+		HandleFunc("/ServeFile", func(w ResponseWriter, r *Request) {
+			ServeFile(w, r, "testdata/file")
+		})
+		l, err := net.Listen("tcp", "127.0.0.1:0")
+		if err != nil {
+			t.Fatal("listen:", err)
+		}
+		serverAddr = l.Addr().String()
+		go Serve(l, nil)
+	})
+}
+
+var ServeFileRangeTests = []struct {
+	start, end int
+	r          string
+	code       int
+}{
+	{0, testFileLength, "", StatusOK},
+	{0, 5, "0-4", StatusPartialContent},
+	{2, testFileLength, "2-", StatusPartialContent},
+	{testFileLength - 5, testFileLength, "-5", StatusPartialContent},
+	{3, 8, "3-7", StatusPartialContent},
+	{0, 0, "20-", StatusRequestedRangeNotSatisfiable},
+}
+
+func TestServeFile(t *testing.T) {
+	startServer(t)
+	var err os.Error
+
+	file, err := ioutil.ReadFile(testFile)
+	if err != nil {
+		t.Fatal("reading file:", err)
+	}
+
+	// set up the Request (re-used for all tests)
+	var req Request
+	req.Header = make(map[string]string)
+	if req.URL, err = ParseURL("http://" + serverAddr + "/ServeFile"); err != nil {
+		t.Fatal("ParseURL:", err)
+	}
+	req.Method = "GET"
+
+	// straight GET
+	_, body := getBody(t, req)
+	if !equal(body, file) {
+		t.Fatalf("body mismatch: got %q, want %q", body, file)
+	}
+
+	// Range tests
+	for _, rt := range ServeFileRangeTests {
+		req.Header["Range"] = "bytes=" + rt.r
+		if rt.r == "" {
+			req.Header["Range"] = ""
+		}
+		r, body := getBody(t, req)
+		if r.StatusCode != rt.code {
+			t.Errorf("range=%q: StatusCode=%d, want %d", rt.r, r.StatusCode, rt.code)
+		}
+		if rt.code == StatusRequestedRangeNotSatisfiable {
+			continue
+		}
+		h := fmt.Sprintf("%d-%d/%d", rt.start, rt.end, testFileLength)
+		if rt.r == "" {
+			h = ""
+		}
+		if r.Header["Content-Range"] != h {
+			t.Errorf("header mismatch: range=%q: got %q, want %q", rt.r, r.Header["Content-Range"], h)
+		}
+		if !equal(body, file[rt.start:rt.end]) {
+			t.Errorf("body mismatch: range=%q: got %q, want %q", rt.r, body, file[rt.start:rt.end])
+		}
+	}
+}
+
+func getBody(t *testing.T, req Request) (*Response, []byte) {
+	r, err := send(&req)
+	if err != nil {
+		t.Fatal(req.URL.String(), "send:", err)
+	}
+	b, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		t.Fatal("reading Body:", err)
+	}
+	return r, b
+}
+
+func equal(a, b []byte) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}