Check for chunked encoding with a new MessageHeaders.contains() method #39

We were incorrectly throwing when there were multiple Transfer-Encoding headers and we weren't matching in cases when a comma separated list was used.

Author: ato

Diff for: README.md

@@ -207,6 +207,7 @@ fields and a body. Header field names are case-insensitvie and may have multiple
                   (String) message.contentType();              // the media type of the body
                  (Headers) message.headers();                  // the header fields
             (List<String>) message.headers().all("Cookie");    // all values of a header
+                 (boolean) message.headers().contains("TE", "deflate"); // tests if a value is present
         (Optional<String>) message.headers().first("Cookie");  // the first value of a header
 (Map<String,List<String>>) message.headers().map();            // views the header fields as a map
         (Optional<String>) message.headers().sole("Location"); // throws if header has multiple values

Diff for: src/org/netpreserve/jwarc/HttpResponse.java

@@ -73,7 +73,7 @@ private static HttpResponse parse(ReadableByteChannel channel, WritableByteChann
         MessageBody body;
         if (withoutBody) {
             body = MessageBody.empty();
-        } else if (headers.sole("Transfer-Encoding").orElse("").equalsIgnoreCase("chunked")) {
+        } else if (headers.contains("Transfer-Encoding", "chunked")) {
             body = new ChunkedBody(channel, buffer);
         } else {
             if (channel instanceof LengthedBody.LengthedReadableByteChannel) {

Diff for: src/org/netpreserve/jwarc/MessageHeaders.java

@@ -13,10 +13,12 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.regex.Pattern;
 
 import static java.util.Collections.emptyList;
 
 public class MessageHeaders {
+    private static Pattern COMMA_SEPARATOR = Pattern.compile("[ \t]*,[ \t]*");
     private Map<String,List<String>> map;
 
     MessageHeaders(Map<String, List<String>> map) {
@@ -56,6 +58,22 @@ public Map<String,List<String>> map() {
         return map;
     }
 
+    /**
+     * Returns true when the given header value is present.
+     *
+     * Fields are interpreted as a comma-separated list and the value is compared case-insensitively.
+     */
+    public boolean contains(String name, String value) {
+        for (String rawValue : all(name)) {
+            for (String splitValue : COMMA_SEPARATOR.split(rawValue)) {
+                if (splitValue.trim().equalsIgnoreCase(value)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
     @Override
     public String toString() {
         return map.toString();

Diff for: test/org/netpreserve/jwarc/MessageHeadersTest.java

@@ -0,0 +1,36 @@
+package org.netpreserve.jwarc;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+import static org.junit.Assert.*;
+
+public class MessageHeadersTest {
+    @Test
+    public void testContains() {
+        assertFalse(headers("Z", "1")
+                .contains("Transfer-Encoding", "chunked"));
+        assertTrue(headers("A", "0", "Transfer-Encoding", "chunked", "Z", "1")
+                .contains("Transfer-Encoding", "chunked"));
+        assertFalse(headers("Transfer-Encoding", "xchunkedx")
+                .contains("Transfer-Encoding", "chunked"));
+        assertFalse(headers("Transfer-Encoding", "gzip chunked")
+                .contains("Transfer-Encoding", "chunked"));
+        assertTrue(headers("Transfer-Encoding", "gzip, chunked, chunked, gzip")
+                .contains("Transfer-Encoding", "chunked"));
+        assertTrue(headers("Transfer-Encoding", "gzip,     \tCHUNKED,,, GZIP")
+                .contains("Transfer-Encoding", "Chunked"));
+    }
+
+    private static MessageHeaders headers(String... headers) {
+        Map<String,List<String>> map = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
+        for (int i = 0; i < headers.length; i += 2) {
+            map.computeIfAbsent(headers[i], (k) -> new ArrayList<>()).add(headers[i + 1]);
+        }
+        return new MessageHeaders(map);
+    }
+}