Support {/var} syntax in UriComponentsBuilder

Issue: SPR-12750

Author: rstoyanchev

spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java

@@ -716,18 +716,35 @@ public void addPathSegments(String... pathSegments) {
 		}
 
 		public void addPath(String path) {
-			if (StringUtils.hasText(path)) {
-				PathSegmentComponentBuilder psBuilder = getLastBuilder(PathSegmentComponentBuilder.class);
-				FullPathComponentBuilder fpBuilder = getLastBuilder(FullPathComponentBuilder.class);
-				if (psBuilder != null) {
-					path = path.startsWith("/") ? path : "/" + path;
-				}
-				if (fpBuilder == null) {
-					fpBuilder = new FullPathComponentBuilder();
-					this.builders.add(fpBuilder);
-				}
-				fpBuilder.append(path);
+			if (!StringUtils.hasText(path)) {
+				return;
+			}
+			int startIndex = path.indexOf("{/");
+			while (startIndex != -1) {
+				String pathToAdd = path.substring(0, startIndex);
+				addPathInternal(pathToAdd);
+
+				int endIndex = path.indexOf("}", startIndex);
+				String pathSegmentToAdd = "{" + path.substring(startIndex + 2, endIndex) + "}";
+				addPathSegments(pathSegmentToAdd);
+
+				path = (endIndex >= path.length()) ? "" : path.substring(endIndex + 1);
+				startIndex = path.indexOf("{/");
+			}
+			addPathInternal(path);
+		}
+
+		private void addPathInternal(String path) {
+			PathSegmentComponentBuilder psBuilder = getLastBuilder(PathSegmentComponentBuilder.class);
+			FullPathComponentBuilder fpBuilder = getLastBuilder(FullPathComponentBuilder.class);
+			if (psBuilder != null) {
+				path = path.startsWith("/") ? path : "/" + path;
+			}
+			if (fpBuilder == null) {
+				fpBuilder = new FullPathComponentBuilder();
+				this.builders.add(fpBuilder);
 			}
+			fpBuilder.append(path);
 		}
 
 		@SuppressWarnings("unchecked")

spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java

@@ -195,6 +195,16 @@ public void fromUriStringQueryParamWithReservedCharInValue() throws URISyntaxExc
 		assertEquals("1USD=?EUR", result.getQueryParams().getFirst("q"));
 	}
 
+	//SPR-12750
+
+	@Test
+	public void fromUriStringWithVariablesRfc6570() {
+		String url = "http://example.com/part1/{/part2}/{var1}/url/{/urlvar}/";
+		UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(url);
+		UriComponents uriComponents = builder.build().expand("part/2", "var/1", "url/var").encode();
+		assertEquals("/part1/part%2F2/var/1/url/url%2Fvar/", uriComponents.getPath());
+	}
+
 	// SPR-10779
 
 	@Test

spring-web/src/test/java/org/springframework/web/util/UriTemplateTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -98,6 +98,19 @@ public void expandMapUnboundVariables() throws Exception {
 		template.expand(uriVariables);
 	}
 
+	//SPR-12750
+
+	@Test
+	public void expandMapForRFC6570() throws Exception {
+		Map<String, String> uriVariables = new HashMap<String, String>(2);
+		uriVariables.put("hotel", "1");
+		uriVariables.put("publicpath", "pics/logo.png");
+		uriVariables.put("scale", "150x150");
+		UriTemplate template = new UriTemplate("/hotels/{hotel}/pic/{/publicpath}/size/{scale}");
+		URI result = template.expand(uriVariables);
+		assertEquals("Invalid expanded template", new URI("/hotels/1/pic/pics%2Flogo.png/size/150x150"), result);
+	}
+
 	@Test
 	public void expandEncoded() throws Exception {
 		UriTemplate template = new UriTemplate("http://example.com/hotel list/{hotel}");