From 836c5c69f02b7e90492b037cd22dda8b2310956c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20Geisendo=CC=88rfer?= <felix@debuggable.com>
Date: Sun, 17 Mar 2013 16:13:32 +0100
Subject: [PATCH] Parse content ranges

---
 src/cmd/tusd/content_range.go      | 74 ++++++++++++++++++++++++++++++
 src/cmd/tusd/content_range_test.go | 54 ++++++++++++++++++++++
 src/cmd/tusd/main.go               | 12 +++--
 3 files changed, 137 insertions(+), 3 deletions(-)
 create mode 100644 src/cmd/tusd/content_range.go
 create mode 100644 src/cmd/tusd/content_range_test.go

diff --git a/src/cmd/tusd/content_range.go b/src/cmd/tusd/content_range.go
new file mode 100644
index 0000000..c1ccc5d
--- /dev/null
+++ b/src/cmd/tusd/content_range.go
@@ -0,0 +1,74 @@
+package main
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+)
+
+var errInvalidRange = errors.New("invalid Content-Range")
+
+type contentRange struct {
+	Start int64
+	End   int64
+	Size  int64
+}
+
+// parseContentRange parse a Content-Range string like "5-10/100".
+// see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.16 .
+// Asterisks "*" will result in End/Size being set to -1.
+func parseContentRange(s string) (*contentRange, error) {
+	const prefix = "bytes "
+	offset := strings.Index(s, prefix)
+	if offset != 0 {
+		return nil, errInvalidRange
+	}
+	s = s[len(prefix):]
+
+	parts := strings.Split(s, "/")
+	if len(parts) != 2 {
+		return nil, errInvalidRange
+	}
+
+	r := new(contentRange)
+
+	if parts[0] == "*" {
+		r.Start = 0
+		r.End = -1
+	} else {
+		offsets := strings.Split(parts[0], "-")
+		if len(offsets) != 2 {
+			return nil, errInvalidRange
+		}
+
+		if offset, err := strconv.ParseInt(offsets[0], 10, 64); err == nil {
+			r.Start = offset
+		} else {
+			return nil, errInvalidRange
+		}
+
+		if offset, err := strconv.ParseInt(offsets[1], 10, 64); err == nil {
+			r.End = offset
+		} else {
+			return nil, errInvalidRange
+		}
+
+		// A byte-content-range-spec with a byte-range-resp-spec whose last-
+		// byte-pos value is less than its first-byte-pos value, or whose
+		// instance-length value is less than or equal to its last-byte-pos value,
+		// is invalid. The recipient of an invalid byte-content-range- spec MUST
+		// ignore it and any content transferred along with it.
+		if r.End <= r.Start {
+			return nil, errInvalidRange
+		}
+	}
+
+	if parts[1] == "*" {
+		r.Size = -1
+		return r, nil
+	} else if size, err := strconv.ParseInt(parts[1], 10, 64); err == nil {
+		r.Size = size
+		return r, nil
+	}
+	return nil, errInvalidRange
+}
diff --git a/src/cmd/tusd/content_range_test.go b/src/cmd/tusd/content_range_test.go
new file mode 100644
index 0000000..680b7cd
--- /dev/null
+++ b/src/cmd/tusd/content_range_test.go
@@ -0,0 +1,54 @@
+package main
+
+import (
+	"regexp"
+	"testing"
+)
+
+var ContentRangeTests = []struct {
+	s    string
+	want contentRange
+	err  string
+}{
+	{s: "bytes 0-5/100", want: contentRange{Start: 0, End: 5, Size: 100}},
+	{s: "bytes 5-20/30", want: contentRange{Start: 5, End: 20, Size: 30}},
+	{s: "bytes */100", want: contentRange{Start: 0, End: -1, Size: 100}},
+	{s: "bytes 5-20/*", want: contentRange{Start: 5, End: 20, Size: -1}},
+	{s: "bytes */*", want: contentRange{Start: 0, End: -1, Size: -1}},
+	{s: "bytes 0-2147483647/2147483648", want: contentRange{Start: 0, End: 2147483647, Size: 2147483648}},
+	{s: "bytes 5-20", err: "invalid"},
+	{s: "bytes 5-5/100", err: "invalid"},
+	{s: "bytes 5-4/100", err: "invalid"},
+	{s: "bytes ", err: "invalid"},
+	{s: "", err: "invalid"},
+}
+
+func TestParseContentRange(t *testing.T) {
+	for _, test := range ContentRangeTests {
+		t.Logf("testing: %s", test.s)
+
+		r, err := parseContentRange(test.s)
+		if test.err != "" {
+			if err == nil {
+				t.Errorf("got no error, but expected: %s", test.err)
+				continue
+			}
+
+			errMatch := regexp.MustCompile(test.err)
+			if !errMatch.MatchString(err.Error()) {
+				t.Errorf("unexpected error: %s, wanted: %s", err, test.err)
+				continue
+			}
+
+			continue
+		} else if err != nil {
+			t.Errorf("unexpected error: %s, wanted: %+v", err, test.want)
+			continue
+		}
+
+		if *r != test.want {
+			t.Errorf("got: %+v, wanted: %+v", r, test.want)
+			continue
+		}
+	}
+}
diff --git a/src/cmd/tusd/main.go b/src/cmd/tusd/main.go
index 3d3e28f..a5b071f 100644
--- a/src/cmd/tusd/main.go
+++ b/src/cmd/tusd/main.go
@@ -31,9 +31,14 @@ func reply(w http.ResponseWriter, code int, message string) {
 }
 
 func createFile(w http.ResponseWriter, r *http.Request) {
-	contentRange := r.Header.Get("Content-Range")
-	if contentRange == "" {
-		reply(w, http.StatusBadRequest, "Content-Range header is required")
+	contentRange, err := parseContentRange(r.Header.Get("Content-Range"))
+	if err != nil {
+		reply(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	if contentRange.End != -1 {
+		reply(w, http.StatusNotImplemented, "File data in initial request.")
 		return
 	}
 
@@ -43,4 +48,5 @@ func createFile(w http.ResponseWriter, r *http.Request) {
 	}
 
 	log.Printf("contentType: %s", contentType)
+	log.Printf("range: %#v", contentRange)
 }