#1458 - Parsing Link instances now supports unquoted attribute values.

Switched from using regular expressions to a simple manual parsing algorithm for the attributes attached to a link. Adapt a couple of broken tests that previously erroneously worked.

Author: odrotbohm

src/main/java/org/springframework/hateoas/Link.java

@@ -47,11 +47,7 @@
 public class Link implements Serializable {
 
 	private static final long serialVersionUID = -9037755944661782121L;
-	private static final String URI_PATTERN = "(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]";
-
 	private static final Pattern URI_AND_ATTRIBUTES_PATTERN = Pattern.compile("<(.*)>;(.*)");
-	private static final Pattern KEY_AND_VALUE_PATTERN = Pattern
-			.compile("(\\w+)=\"(\\p{Lower}[\\p{Lower}\\p{Digit}.\\-\\s]*|" + URI_PATTERN + ")\"");
 
 	public static final String ATOM_NAMESPACE = "http://www.w3.org/2005/Atom";
 
@@ -515,11 +511,20 @@ private static Map<String, String> getAttributeMap(String source) {
 			return Collections.emptyMap();
 		}
 
+		String[] parts = source.split(";");
 		Map<String, String> attributes = new HashMap<>();
-		Matcher matcher = KEY_AND_VALUE_PATTERN.matcher(source);
 
-		while (matcher.find()) {
-			attributes.put(matcher.group(1), matcher.group(2));
+		for (String part : parts) {
+
+			int delimiter = part.indexOf('=');
+
+			String key = part.substring(0, delimiter).trim();
+			String value = part.substring(delimiter + 1).trim();
+
+			// Potentially unquote value
+			value = value.startsWith("\"") ? value.substring(1, value.length() - 1) : value;
+
+			attributes.put(key, value);
 		}
 
 		return attributes;

src/main/java/org/springframework/hateoas/Links.java

@@ -45,7 +45,7 @@
 public class Links implements Iterable<Link> {
 
 	public static final Links NONE = new Links(Collections.emptyList());
-	private static final Pattern LINK_HEADER_PATTERN = Pattern.compile("(<[^>]*>(;\\s*\\w+=\"[^\"]*\")+)");
+	private static final Pattern LINK_HEADER_PATTERN = Pattern.compile("(<[^>]*>(;\\s*\\w+=\"?[^\"]*\"?)+)");
 
 	private final List<Link> links;
 

src/test/java/org/springframework/hateoas/LinkUnitTest.java

@@ -131,7 +131,7 @@ void parsesRFC8288HeaderIntoLink() {
 
 			softly.assertThat(Link.valueOf("</something>;rel=\"foo\"")).isEqualTo(Link.of("/something", "foo"));
 			softly.assertThat(Link.valueOf("</something>;rel=\"foo\";title=\"Some title\""))
-					.isEqualTo(Link.of("/something", "foo"));
+					.isEqualTo(Link.of("/something", "foo").withTitle("Some title"));
 			softly.assertThat(Link.valueOf("</customer/1>;" //
 					+ "rel=\"self\";" //
 					+ "hreflang=\"en\";" //

src/test/java/org/springframework/hateoas/LinksUnitTest.java

@@ -257,6 +257,13 @@ void basics() {
 		assertThat(one.hashCode()).isEqualTo(anotherOne.hashCode());
 	}
 
+	@Test // #1458
+	void supportsUnquotedAttributes() {
+
+		assertThat(Links.parse("<https://url.com?page=1>; rel=first").getRequiredLink("first").getHref())
+				.isEqualTo("https://url.com?page=1");
+	}
+
 	@Value(staticConstructor = "of")
 	static class NamedLinks {
 		String name;

src/test/java/org/springframework/hateoas/mediatype/hal/HalLinkDiscovererUnitTest.java

@@ -63,7 +63,7 @@ void discoversAllTheLinkAttributes() throws IOException {
 				+ "title=\"pdf customer copy\";" //
 				+ "type=\"portable document\";" //
 				+ "deprecation=\"https://example.com/customers/deprecated\";" //
-				+ "profile=\"my-profile\"" //
+				+ "profile=\"my-profile\";" //
 				+ "name=\"my-name\"");
 
 		assertThat(getDiscoverer().findLinkWithRel(IanaLinkRelations.SELF.value(), linkText)) //

src/test/java/org/springframework/hateoas/mediatype/hal/forms/HalFormsLinkDiscovererUnitTest.java

@@ -62,7 +62,7 @@ void discoversAllTheLinkAttributes() throws IOException {
 				+ "title=\"pdf customer copy\";" //
 				+ "type=\"portable document\";" //
 				+ "deprecation=\"https://example.com/customers/deprecated\";" //
-				+ "profile=\"my-profile\"" //
+				+ "profile=\"my-profile\";" //
 				+ "name=\"my-name\"");
 
 		assertThat(getDiscoverer().findLinkWithRel(IanaLinkRelations.SELF, linkText)) //