backport HttpHeaderParser

Author: jan-elastic

test/framework/src/main/java/org/elasticsearch/test/fixture/HttpHeaderParser.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.test.fixture;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public enum HttpHeaderParser {
+    ;
+
+    private static final Pattern RANGE_HEADER_PATTERN = Pattern.compile("bytes=([0-9]+)-([0-9]+)");
+
+    /**
+     * Parse a "Range" header
+     *
+     * Note: only a single bounded range is supported (e.g. <code>Range: bytes={range_start}-{range_end}</code>)
+     *
+     * @see <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Range">MDN: Range header</a>
+     * @param rangeHeaderValue The header value as a string
+     * @return a {@link Range} instance representing the parsed value, or null if the header is malformed
+     */
+    public static Range parseRangeHeader(String rangeHeaderValue) {
+        final Matcher matcher = RANGE_HEADER_PATTERN.matcher(rangeHeaderValue);
+        if (matcher.matches()) {
+            try {
+                return new Range(Long.parseLong(matcher.group(1)), Long.parseLong(matcher.group(2)));
+            } catch (NumberFormatException e) {
+                return null;
+            }
+        }
+        return null;
+    }
+
+    public record Range(long start, long end) {}
+}

test/framework/src/test/java/org/elasticsearch/http/HttpHeaderParserTests.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.http;
+
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.test.ESTestCase;
+import org.elasticsearch.test.fixture.HttpHeaderParser;
+
+import java.math.BigInteger;
+
+public class HttpHeaderParserTests extends ESTestCase {
+
+    public void testParseRangeHeader() {
+        final long start = randomLongBetween(0, 10_000);
+        final long end = randomLongBetween(start, start + 10_000);
+        assertEquals(new HttpHeaderParser.Range(start, end), HttpHeaderParser.parseRangeHeader("bytes=" + start + "-" + end));
+    }
+
+    public void testParseRangeHeaderInvalidLong() {
+        final BigInteger longOverflow = BigInteger.valueOf(Long.MAX_VALUE).add(BigInteger.ONE).add(randomBigInteger());
+        assertNull(HttpHeaderParser.parseRangeHeader("bytes=123-" + longOverflow));
+        assertNull(HttpHeaderParser.parseRangeHeader("bytes=" + longOverflow + "-123"));
+    }
+
+    public void testParseRangeHeaderMultipleRangesNotMatched() {
+        assertNull(
+            HttpHeaderParser.parseRangeHeader(
+                Strings.format(
+                    "bytes=%d-%d,%d-%d",
+                    randomIntBetween(0, 99),
+                    randomIntBetween(100, 199),
+                    randomIntBetween(200, 299),
+                    randomIntBetween(300, 399)
+                )
+            )
+        );
+    }
+
+    public void testParseRangeHeaderEndlessRangeNotMatched() {
+        assertNull(HttpHeaderParser.parseRangeHeader(Strings.format("bytes=%d-", randomLongBetween(0, Long.MAX_VALUE))));
+    }
+
+    public void testParseRangeHeaderSuffixLengthNotMatched() {
+        assertNull(HttpHeaderParser.parseRangeHeader(Strings.format("bytes=-%d", randomLongBetween(0, Long.MAX_VALUE))));
+    }
+}