/*
* Copyright 2002-2017 the original author or authors.
*
* 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 org.springframework.http;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.springframework.core.io.InputStreamResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.ResourceRegion;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
/**
* Represents an HTTP (byte) range for use with the HTTP {@code "Range"} header.
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @since 4.2
* @see <a href="http://tools.ietf.org/html/rfc7233">HTTP/1.1: Range Requests</a>
* @see HttpHeaders#setRange(List)
* @see HttpHeaders#getRange()
*/
public abstract class HttpRange {
private static final String BYTE_RANGE_PREFIX = "bytes=";
/**
* Turn a {@code Resource} into a {@link ResourceRegion} using the range
* information contained in the current {@code HttpRange}.
* @param resource the {@code Resource} to select the region from
* @return the selected region of the given {@code Resource}
* @since 4.3
*/
public ResourceRegion toResourceRegion(Resource resource) {
// Don't try to determine contentLength on InputStreamResource - cannot be read afterwards...
// Note: custom InputStreamResource subclasses could provide a pre-calculated content length!
Assert.isTrue(resource.getClass() != InputStreamResource.class,
"Cannot convert an InputStreamResource to a ResourceRegion");
try {
long contentLength = resource.contentLength();
Assert.isTrue(contentLength > 0, "Resource content length should be > 0");
long start = getRangeStart(contentLength);
long end = getRangeEnd(contentLength);
return new ResourceRegion(resource, start, end - start + 1);
}
catch (IOException ex) {
throw new IllegalArgumentException("Failed to convert Resource to ResourceRegion", ex);
}
}
/**
* Return the start of the range given the total length of a representation.
* @param length the length of the representation
* @return the start of this range for the representation
*/
public abstract long getRangeStart(long length);
/**
* Return the end of the range (inclusive) given the total length of a representation.
* @param length the length of the representation
* @return the end of the range for the representation
*/
public abstract long getRangeEnd(long length);
/**
* Create an {@code HttpRange} from the given position to the end.
* @param firstBytePos the first byte position
* @return a byte range that ranges from {@code firstPos} till the end
* @see <a href="http://tools.ietf.org/html/rfc7233#section-2.1">Byte Ranges</a>
*/
public static HttpRange createByteRange(long firstBytePos) {
return new ByteRange(firstBytePos, null);
}
/**
* Create a {@code HttpRange} from the given fist to last position.
* @param firstBytePos the first byte position
* @param lastBytePos the last byte position
* @return a byte range that ranges from {@code firstPos} till {@code lastPos}
* @see <a href="http://tools.ietf.org/html/rfc7233#section-2.1">Byte Ranges</a>
*/
public static HttpRange createByteRange(long firstBytePos, long lastBytePos) {
return new ByteRange(firstBytePos, lastBytePos);
}
/**
* Create an {@code HttpRange} that ranges over the last given number of bytes.
* @param suffixLength the number of bytes for the range
* @return a byte range that ranges over the last {@code suffixLength} number of bytes
* @see <a href="http://tools.ietf.org/html/rfc7233#section-2.1">Byte Ranges</a>
*/
public static HttpRange createSuffixRange(long suffixLength) {
return new SuffixByteRange(suffixLength);
}
/**
* Parse the given, comma-separated string into a list of {@code HttpRange} objects.
* <p>This method can be used to parse an {@code Range} header.
* @param ranges the string to parse
* @return the list of ranges
* @throws IllegalArgumentException if the string cannot be parsed
*/
public static List<HttpRange> parseRanges(String ranges) {
if (!StringUtils.hasLength(ranges)) {
return Collections.emptyList();
}
if (!ranges.startsWith(BYTE_RANGE_PREFIX)) {
throw new IllegalArgumentException("Range '" + ranges + "' does not start with 'bytes='");
}
ranges = ranges.substring(BYTE_RANGE_PREFIX.length());
String[] tokens = StringUtils.tokenizeToStringArray(ranges, ",");
List<HttpRange> result = new ArrayList<>(tokens.length);
for (String token : tokens) {
result.add(parseRange(token));
}
return result;
}
private static HttpRange parseRange(String range) {
Assert.hasLength(range, "Range String must not be empty");
int dashIdx = range.indexOf('-');
if (dashIdx > 0) {
long firstPos = Long.parseLong(range.substring(0, dashIdx));
if (dashIdx < range.length() - 1) {
Long lastPos = Long.parseLong(range.substring(dashIdx + 1, range.length()));
return new ByteRange(firstPos, lastPos);
}
else {
return new ByteRange(firstPos, null);
}
}
else if (dashIdx == 0) {
long suffixLength = Long.parseLong(range.substring(1));
return new SuffixByteRange(suffixLength);
}
else {
throw new IllegalArgumentException("Range '" + range + "' does not contain \"-\"");
}
}
/**
* Convert each {@code HttpRange} into a {@code ResourceRegion}, selecting the
* appropriate segment of the given {@code Resource} using HTTP Range information.
* @param ranges the list of ranges
* @param resource the resource to select the regions from
* @return the list of regions for the given resource
* @since 4.3
*/
public static List<ResourceRegion> toResourceRegions(List<HttpRange> ranges, Resource resource) {
if (CollectionUtils.isEmpty(ranges)) {
return Collections.emptyList();
}
List<ResourceRegion> regions = new ArrayList<>(ranges.size());
for (HttpRange range : ranges) {
regions.add(range.toResourceRegion(resource));
}
return regions;
}
/**
* Return a string representation of the given list of {@code HttpRange} objects.
* <p>This method can be used to for an {@code Range} header.
* @param ranges the ranges to create a string of
* @return the string representation
*/
public static String toString(Collection<HttpRange> ranges) {
Assert.notEmpty(ranges, "Ranges Collection must not be empty");
StringBuilder builder = new StringBuilder(BYTE_RANGE_PREFIX);
for (Iterator<HttpRange> iterator = ranges.iterator(); iterator.hasNext(); ) {
HttpRange range = iterator.next();
builder.append(range);
if (iterator.hasNext()) {
builder.append(", ");
}
}
return builder.toString();
}
/**
* Represents an HTTP/1.1 byte range, with a first and optional last position.
* @see <a href="http://tools.ietf.org/html/rfc7233#section-2.1">Byte Ranges</a>
* @see HttpRange#createByteRange(long)
* @see HttpRange#createByteRange(long, long)
*/
private static class ByteRange extends HttpRange {
private final long firstPos;
private final Long lastPos;
public ByteRange(long firstPos, Long lastPos) {
assertPositions(firstPos, lastPos);
this.firstPos = firstPos;
this.lastPos = lastPos;
}
private void assertPositions(long firstBytePos, Long lastBytePos) {
if (firstBytePos < 0) {
throw new IllegalArgumentException("Invalid first byte position: " + firstBytePos);
}
if (lastBytePos != null && lastBytePos < firstBytePos) {
throw new IllegalArgumentException("firstBytePosition=" + firstBytePos +
" should be less then or equal to lastBytePosition=" + lastBytePos);
}
}
@Override
public long getRangeStart(long length) {
return this.firstPos;
}
@Override
public long getRangeEnd(long length) {
if (this.lastPos != null && this.lastPos < length) {
return this.lastPos;
}
else {
return length - 1;
}
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof ByteRange)) {
return false;
}
ByteRange otherRange = (ByteRange) other;
return (this.firstPos == otherRange.firstPos &&
ObjectUtils.nullSafeEquals(this.lastPos, otherRange.lastPos));
}
@Override
public int hashCode() {
return (ObjectUtils.nullSafeHashCode(this.firstPos) * 31 +
ObjectUtils.nullSafeHashCode(this.lastPos));
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append(this.firstPos);
builder.append('-');
if (this.lastPos != null) {
builder.append(this.lastPos);
}
return builder.toString();
}
}
/**
* Represents an HTTP/1.1 suffix byte range, with a number of suffix bytes.
* @see <a href="http://tools.ietf.org/html/rfc7233#section-2.1">Byte Ranges</a>
* @see HttpRange#createSuffixRange(long)
*/
private static class SuffixByteRange extends HttpRange {
private final long suffixLength;
public SuffixByteRange(long suffixLength) {
if (suffixLength < 0) {
throw new IllegalArgumentException("Invalid suffix length: " + suffixLength);
}
this.suffixLength = suffixLength;
}
@Override
public long getRangeStart(long length) {
if (this.suffixLength < length) {
return length - this.suffixLength;
}
else {
return 0;
}
}
@Override
public long getRangeEnd(long length) {
return length - 1;
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof SuffixByteRange)) {
return false;
}
SuffixByteRange otherRange = (SuffixByteRange) other;
return (this.suffixLength == otherRange.suffixLength);
}
@Override
public int hashCode() {
return Long.hashCode(this.suffixLength);
}
@Override
public String toString() {
return "-" + this.suffixLength;
}
}
}