Restructure minio api, move signature checks from utils to Api.

pkg/api/range.go

@@ -0,0 +1,119 @@
+/*
+ * Mini Object Storage, (C) 2015 Minio, Inc.
+ *
+ * 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 api
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"net/http"
+)
+
+const (
+	b = "bytes="
+)
+
+// HttpRange specifies the byte range to be sent to the client.
+type httpRange struct {
+	start, length, size int64
+}
+
+// GetContentRange populate range header
+func (r *httpRange) getContentRange() string {
+	return fmt.Sprintf("bytes %d-%d/%d", r.start, r.start+r.length-1, r.size)
+}
+
+// Grab new range from request header
+func newRange(req *http.Request, size int64) (*httpRange, error) {
+	r := &httpRange{
+		start:  0,
+		length: 0,
+		size:   0,
+	}
+	r.size = size
+	if s := req.Header.Get("Range"); s != "" {
+		err := r.parseRange(s)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return r, nil
+}
+
+// parseRange parses a Range header string as per RFC 2616.
+func (r *httpRange) parseRange(s string) error {
+	if s == "" {
+		return errors.New("header not present")
+	}
+	if !strings.HasPrefix(s, b) {
+		return errors.New("invalid range")
+	}
+
+	ras := strings.Split(s[len(b):], ",")
+	if len(ras) == 0 {
+		return errors.New("invalid request")
+	}
+	// Just pick the first one and ignore the rest, we only support one range per object
+	if len(ras) > 1 {
+		return errors.New("multiple ranges specified")
+	}
+
+	ra := strings.TrimSpace(ras[0])
+	if ra == "" {
+		return errors.New("invalid range")
+	}
+	i := strings.Index(ra, "-")
+	if i < 0 {
+		return errors.New("invalid range")
+	}
+	start, end := strings.TrimSpace(ra[:i]), strings.TrimSpace(ra[i+1:])
+	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 errors.New("invalid range")
+		}
+		if i > r.size {
+			i = r.size
+		}
+		r.start = r.size - i
+		r.length = r.size - r.start
+	} else {
+		i, err := strconv.ParseInt(start, 10, 64)
+		if err != nil || i > r.size || i < 0 {
+			return errors.New("invalid range")
+		}
+		r.start = i
+		if end == "" {
+			// If no end is specified, range extends to end of the file.
+			r.length = r.size - r.start
+		} else {
+			i, err := strconv.ParseInt(end, 10, 64)
+			if err != nil || r.start > i {
+				return errors.New("invalid range")
+			}
+			if i >= r.size {
+				i = r.size - 1
+			}
+			r.length = i - r.start + 1
+		}
+	}
+	return nil
+}