http: handle request range like Amazon S3. (#2112)

Fixes #2098

httprange_test.go

@@ -0,0 +1,67 @@
+/*
+ * Minio Cloud Storage, (C) 2016 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 main
+
+import "testing"
+
+// Test parseRequestRange()
+func TestParseRequestRange(t *testing.T) {
+	// Test success cases.
+	successCases := []struct {
+		rangeString  string
+		firstBytePos int64
+		lastBytePos  int64
+		length       int64
+	}{
+		{"bytes=2-5", 2, 5, 4},
+		{"bytes=2-20", 2, 9, 8},
+		{"bytes=2-", 2, 9, 8},
+		{"bytes=-4", 6, 9, 4},
+	}
+
+	for _, successCase := range successCases {
+		hrange, err := parseRequestRange(successCase.rangeString, 10)
+		if err != nil {
+			t.Fatalf("expected: <nil>, got: %s", err)
+		}
+
+		if hrange.firstBytePos != successCase.firstBytePos {
+			t.Fatalf("expected: %d, got: %d", successCase.firstBytePos, hrange.firstBytePos)
+		}
+
+		if hrange.lastBytePos != successCase.lastBytePos {
+			t.Fatalf("expected: %d, got: %d", successCase.lastBytePos, hrange.lastBytePos)
+		}
+		if hrange.getLength() != successCase.length {
+			t.Fatalf("expected: %d, got: %d", successCase.length, hrange.getLength())
+		}
+	}
+
+	// Test invalid range strings.
+	invalidRangeStrings := []string{"", "2-5", "bytes= 2-5", "bytes=2 - 5", "bytes=0-0,-1", "bytes=5-2", "bytes=2-5 ", "bytes=2--5"}
+	for _, rangeString := range invalidRangeStrings {
+		if _, err := parseRequestRange(rangeString, 10); err == nil {
+			t.Fatalf("expected: an error, got: <nil>")
+		}
+	}
+
+	// Test error range strings.
+	errorRangeString := "bytes=-0"
+	if _, err := parseRequestRange(errorRangeString, 10); err != errInvalidRange {
+		t.Fatalf("expected: %s, got: %s", errInvalidRange, err)
+	}
+}